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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
FEATURES
D Unity Gain Stability
D Wide Bandwidth: 1 GHz
D High Slew Rate: 970 V/µs
D Low Distortion
APPLICATIONS
D High Linearity ADC Preamplifier
D Differential to Single-Ended Conversion
D DAC Output Buffer
D Active Filtering
D Video Applications
− −90 dBc THD at 30 MHz
D High Output Drive, IO = 200 mA
D Excellent Video Performance
D
THS4211
− 130 MHz Bandwidth (0.1 dB, G = 2)
− 0.007% Differential Gain
− 0.003° Differential Phase
Supply Voltages
− +5 V, ±5 V, +12 V, +15 V
Power Down Functionality (THS4215)
NC
IN−
IN+
VS−
D
D Evaluation Module Available
DESCRIPTION
The THS4211 and THS4215 are high slew rate, unity gain
stable voltage feedback amplifiers designed to run from
supply voltages as low as 5 V and as high as 15 V. The
THS4215 offers the same performance as the THS4211
with the addition of power-down capability. The
combination of high slew rate, wide bandwidth, low
distortion, and unity gain stability make the THS4211 and
THS4215 high performance devices across multiple ac
specifications.
7
3
6
4
5
NC
VS+
VOUT
NC
RELATED DEVICES
DEVICE
DESCRIPTION
THS4271
1.4 GHz voltage feedback amplifier
THS4503
Wideband fully differential amplifier
THS3202
Dual, wideband current feedback amplifier
HARMONIC DISTORTION
vs
FREQUENCY
+5 V
−50
50 Ω
Gain = 2
Rf = 392 Ω
RL = 150 Ω
VO = 2 VPP
VS = ±5 V
49.9 Ω
THS4211
_
−5 V
392 Ω
392 Ω
NOTE: Power supply decoupling capacitors not shown
VO
Harmonic Distortion − dBc
−55
+
VI
8
2
Designers using the THS4211 are rewarded with higher
dynamic range over a wider frequency band without the
stability concerns of decompensated amplifiers. The
devices are available in SOIC, MSOP with PowerPAD,
and leadless MSOP with PowerPAD packages.
Low-Distortion, Wideband Application Circuit
50 Ω Source
1
−60
−65
−70
−75
−80
HD2
−85
HD3
−90
−95
−100
1
10
f − Frequency − MHz
100
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments.
!"#$%&" ' ()##*& %' "! +),-(%&" .%&*/ #".)(&'
("!"#$ &" '+*(!(%&"' +*# &0* &*#$' "! *1%'
')$*&' '&%.%#. 2%##%&3/
#".)(&" +#"(*''4 ."*' "& *(*''%#-3 (-).* &*'&4 "! %-- +%#%$*&*#'/
Copyright 2002 − 2004, Texas Instruments Incorporated
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
This integrated circuit can be damaged by ESD. Texas
Instruments recommends that all integrated circuits be
handled with appropriate precautions. Failure to observe
proper handling and installation procedures can cause damage.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted(1)
UNIT
16.5 V
Supply voltage, VS
±VS
Input voltage, VI
Output current, IO (2)
Continuous power dissipation
See Dissipation Rating Table
Maximum junction temperature, TJ (3)
150°C
Maximum junction temperature, continuous
operation, long term reliability TJ (4)
125°C
Operating free-air temperature range, TA
−40°C to 85°C
Storage temperature range, Tstg
−65°C to 150°C
Lead temperature
1,6 mm (1/16 inch) from case for 10 seconds
PACKAGE DISSIPATION RATINGS
300°C
HBM
4000 V
CDM
ESD ratings:
ESD damage can range from subtle performance degradation to
complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could
cause the device not to meet its published specifications.
100 mA
1500 V
MM
200 V
PACKAGE
θJC
(°C/W)
θJA(1)
(°C/W)
POWER RATING(2)
TA ≤ 25°C
1.02 W
TA = 85°C
410 mW
D (8 pin)
38.3
97.5
DGN (8 pin)
4.7
58.4
1.71 W
685 mW
DGK (8 pin)
54.2
260
385 mW
154 mW
DRB (8 pin)
5
45.8
2.18 W
873 mW
(1) This data was taken using the JEDEC standard High-K test PCB.
(2) Power rating is determined with a junction temperature of 125°C.
This is the point where distortion starts to substantially increase.
Thermal management of the final PCB should strive to keep the
junction temperature at or below 125°C for best performance and
long term reliability.
(1)
Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods
may degrade device reliability. These are stress ratings only, and
functional operation of the device at these or any other conditions
beyond those specified is not implied.
(2) The THS4211/5 may incorporate a PowerPAD on the underside
of the chip. This acts as a heat sink and must be connected to a
thermally dissipative plane for proper power dissipation. Failure
to do so may result in exceeding the maximum junction
temperature which could permanently damage the device. See TI
technical briefs SLMA002 and SLMA004 for more information
about utilizing the PowerPAD thermally enhanced package.
(3) The absolute maximum temperature under any condition is
limited by the constraints of the silicon process.
(4) The maximum junction temperature for continuous operation is
limited by package constraints. Operation above this temperature
may result in reduced reliability and/or lifetime of the device.
RECOMMENDED OPERATING CONDITIONS
Supply voltage,
(VS+ and VS−)
MIN
MAX
Dual supply
±2.5
±7.5
Single supply
5
15
VS− + 1.2
VS+ − 1.2
Input common-mode voltage
range
UNIT
V
V
PACKAGING/ORDERING INFORMATION
TEMPERATURE
−40°C to 85°C
PLASTIC
SMALL OUTLINE
(D) (1)
ORDERABLE PACKAGE AND NUMBER
PLASTIC MSOP (1)
LEADLESS MSOP 8 (2)
PowerPAD
(DRB)
PACKAGE
MARKING
(DGN)
PLASTIC MSOP (1)
PACKAGE
MARKING
(DGK)
PACKAGE
MARKING
THS4211D
THS4211DRB
BET
THS4211DGN
BFN
THS4211DGK
BEJ
THS4215D
THS4215DRB
BEU
THS4215DGN
BFQ
THS4215DGK
BEZ
(1) All packages are available taped and reeled. The R suffix standard quantity is 2500 (e.g., THS4211DGNR).
(2) All packages are available taped and reeled. The R suffix standard quantity is 3000. The T suffix standard quantity is 250 (e.g., THS4211DBVT).
PIN ASSIGNMENTS
(TOP VIEW)
2
D, DRB, DGK, DGN
THS4211
NC
1
8
NC
IN−
2
7
VS+
IN+
3
6
VS−
4
5
(TOP VIEW)
REF
D, DRB, DGK, DGN
THS4215
1
8
PD
IN−
2
7
VS+
VOUT
IN+
3
6
VOUT
NC
VS−
4
5
NC
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
ELECTRICAL CHARACTERISTICS VS = ±5 V
RF = 392 Ω, RL = 499 Ω, G = +1, unless otherwise noted.
TYP
PARAMETER
TEST CONDITIONS
25°C
OVER TEMPERATURE
25°C
0°C TO
70°C
−40°C
TO 85°C
UNITS
MIN/
TYP/
MAX
AC PERFORMANCE
G = 1,
POUT = −7 dBm
G = −1, POUT = −16 dBm
G = 2, POUT = −16 dBm
1
GHz
Typ
325
MHz
Typ
325
MHz
Typ
G = 5,
POUT = −16 dBm
G = 10, POUT = −16 dBm
70
MHz
Typ
35
MHz
Typ
G = 1,
70
MHz
Typ
350
MHz
Typ
77
MHz
Typ
970
V/µs
Typ
G = −1, VO = 2 V Step
G = −1, VO = 4 V Step
850
V/µs
Typ
22
ns
Typ
G = −1, VO = 4 V Step
G = 1, VO = 1 VPP, f = 30 MHz
55
ns
Typ
Second harmonic distortion
RL = 150 Ω
RL = 499 Ω
−78
dBc
Typ
−90
dBc
Typ
Third harmonic distortion
RL = 150 Ω
RL = 499 Ω
−100
dBc
Typ
−100
dBc
Typ
Harmonic distortion
G = 2,
−68
dBc
Typ
RL = 499 Ω
RL = 150 Ω
−70
dBc
Typ
−80
dBc
Typ
−82
dBc
Typ
Third order intermodulation (IMD3)
RL = 499 Ω
G = 2, VO = 2 VPP, RL = 150 Ω,
f = 70 MHz
−53
dBc
Typ
Third order output intercept (OIP3)
G = 2, VO = 2 VPP, RL = 150 Ω,
f = 70 MHz
32
dBm
Typ
Differential gain (NTSC, PAL)
G = 2,
0.007
%
Typ
Differential phase (NTSC, PAL)
G = 2,
0.003
_
Typ
Input voltage noise
f = 1 MHz
7
nV/√Hz
Typ
Input current noise
f = 1 MHz
4
pA√Hz
Typ
Small signal bandwidth
0.1 dB flat bandwidth
Gain bandwidth product
Full-power bandwidth
Slew rate
Settling time to 0.1%
Settling time to 0.01%
Harmonic distortion
Second harmonic distortion
Third harmonic distortion
POUT = −7 dBm
G > 10 , f = 1 MHz
G = −1, VO = 2 Vp
G = 1, VO = 2 V Step
VO = 2 VPP, f = 30 MHz
RL = 150 Ω
RL = 150 Ω
RL = 150 Ω
DC PERFORMANCE
Open-loop voltage gain (AOL)
Input offset voltage
Average offset voltage drift
Input bias current
Average bias current drift
Input offset current
Average offset current drift
VO = ±0.3 V,
VCM = 0 V
RL = 499 Ω
70
65
62
60
dB
Min
3
12
14
14
mV
Max
VCM = 0 V
VCM = 0 V
±40
±40
µV/°C
Typ
7
15
18
20
µA
Max
VCM = 0 V
VCM = 0 V
±10
±10
nA/°C
Typ
0.3
6
7
8
µA
Max
±10
±10
nA/°C
Typ
VCM = 0 V
3
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
ELECTRICAL CHARACTERISTICS VS = ±5 V (continued)
RF = 392 Ω, RL = 499 Ω, G = +1, unless otherwise noted.
TYP
PARAMETER
TEST CONDITIONS
OVER TEMPERATURE
UNITS
MIN/
TYP/
MAX
±3.6
V
Min
48
dB
Min
4
MΩ
Typ
0.3 / 0.2
pF
Typ
25°C
25°C
0°C to
70°C
±4
±3.8
±3.7
56
52
50
−40°C to
85°C
INPUT CHARACTERISTICS
Common-mode input range
Input resistance
VCM = ± 1 V
Common-mode
Input capacitance
Common-mode / differential
Common-mode rejection ratio
OUTPUT CHARACTERISTICS
±4.0
±3.8
±3.7
±3.6
V
Min
220
200
190
180
mA
Min
Output current (sinking)
RL = 10 Ω
RL = 10 Ω
170
140
130
120
mA
Min
Output impedance
f = 1 MHz
0.3
Ω
Typ
Output voltage swing
Output current (sourcing)
POWER SUPPLY
Specified operating voltage
±5
±7.5
±7.5
±7.5
V
Max
Maximum quiescent current
19
22
23
24
mA
Max
Minimum quiescent current
19
16
15
14
mA
Min
64
58
54
54
dB
Min
65
60
56
56
dB
Min
Power supply rejection (+PSRR)
Power supply rejection (−PSRR)
VS+ = 5.5 V to 4.5 V, VS− = 5 V
VS+ = 5 V, VS− = −5.5 V to −4.5 V
POWER-DOWN CHARACTERISTICS (THS4215 ONLY)
Power-down voltage level
Power-down quiescent current
REF = 0 V,
or VS−
Enable
REF = VS+ or
Floating
Enable
Power-down
Power-down
REF+1.8
V
Min
REF+1
V
Max
REF−1
V
Min
REF−1.5
V
Max
PD = Ref +1.0 V, Ref = 0 V
650
850
900
1000
µA
Max
PD = Ref −1.5 V, Ref = 5 V
450
650
800
900
µA
Max
µs
Typ
Turnon time delay(t(ON))
50% of final supply current value
4
Turnoff time delay (t(Off))
50% of final supply current value
3
µs
Typ
4
GΩ
Typ
250
kΩ
Typ
Input impedance
Output impedance
4
f = 1 MHz
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
ELECTRICAL CHARACTERISTICS VS = 5 V
RF = 392 Ω, RL = 499 Ω, G = +1, unless otherwise noted
TYP
PARAMETER
TEST CONDITIONS
25°C
OVER TEMPERATURE
25°C
0°C to
70°C
−40°C to
85°C
UNITS
MIN/
TYP/
MAX
AC PERFORMANCE
G = 1,
POUT = −7 dBm
G = −1, POUT = −16 dBm
G = 2, POUT = −16 dBm
980
MHz
Typ
300
MHz
Typ
300
MHz
Typ
G = 5,
POUT = −16 dBm
G = 10, POUT = −16 dBm
65
MHz
Typ
30
MHz
Typ
G = 1,
90
MHz
Typ
300
MHz
Typ
64
MHz
Typ
800
V/µs
Typ
G = −1, VO = 2 V Step
G = −1, VO = 2 V Step
750
V/µs
Typ
22
ns
Typ
G = −1, VO = 2 V Step
G = 1, VO = 1 VPP, f = 30 MHz
84
ns
Typ
Second harmonic distortion
RL = 150 Ω
RL = 499 Ω
−60
dBc
Typ
−60
dBc
Typ
Third harmonic distortion
RL = 150 Ω
RL = 499 Ω
−68
dBc
Typ
−68
dBc
Typ
Third order intermodulation (IMD3)
G = 1, VO = 1 VPP , RL = 150 Ω,
f = 70 MHz
−70
dBc
Typ
Third order output intercept (OIP3)
G = 1, VO = 1 VPP, RL = 150 Ω,
f = 70 MHz
34
dBm
Typ
Input-voltage noise
f = 1 MHz
7
nV/√Hz
Typ
Input-current noise
f = 10 MHz
4
pA/√Hz
Typ
Small signal bandwidth
0.1 dB flat bandwidth
Gain bandwidth product
Full-power bandwidth
Slew rate
Settling time to 0.1%
Settling time to 0.01%
Harmonic distortion
POUT = −7 dBm
G > 10, f = 1 MHz
G = −1, VO = 2 Vp
G = 1, VO = 2 V Step
DC PERFORMANCE
Open-loop voltage gain (AOL)
Input offset voltage
Average offset voltage drift
Input bias current
Average bias current drift
Input offset current
Average offset current drift
VO = ± 0.3 V,
VCM = VS/2
RL = 499 Ω
68
63
60
60
dB
Min
3
12
14
14
mV
Max
VCM = VS/2
VCM = VS/2
±40
±40
µV/°C
Typ
7
15
17
18
µA
Max
VCM = VS/2
VCM = VS/2
±10
±10
nA/°C
Typ
0.3
6
7
8
µA
Max
±10
±10
nA/°C
Typ
VCM = VS/2
INPUT CHARACTERISTICS
Common-mode input range
1/4
1.2 / 3.8
1.3 / 3.7
1.4 / 3.6
V
Min
54
50
48
45
dB
Min
Input resistance
VCM = ± 0.5 V, VO = 2.5 V
Common-mode
4
MΩ
Typ
Input capacitance
Common-mode / differential
0.3 / 0.2
pF
Typ
Common-mode rejection ratio
OUTPUT CHARACTERISTICS
Output voltage swing
1/4
1.2 / 3.8
1.3 / 3.7
1.4 / 3.6
V
Min
230
210
190
180
mA
Min
Output current (sinking)
RL = 10 Ω
RL = 10 Ω
150
120
100
90
mA
Min
Output impedance
f = 1 MHz
0.3
Ω
Typ
Output current (sourcing)
5
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
ELECTRICAL CHARACTERISTICS VS = 5 V (continued)
RF = 392 Ω, RL = 499 Ω, G = +1, unless otherwise noted
TYP
PARAMETER
OVER TEMPERATURE
UNITS
MIN/
TYP/
MAX
15
V
Max
24
mA
Max
15
14
mA
Min
58
54
54
dB
Min
60
56
56
dB
Min
REF+1.8
V
Min
Power down
REF+1
V
Max
Enable
REF−1
V
Min
REF−1.5
V
Max
TEST CONDITIONS
25°C
25°C
0°C to
70°C
Specified operating voltage
5
15
15
Maximum quiescent current
19
22
23
Minimum quiescent current
19
16
63
65
−40°C to
85°C
POWER SUPPLY
Power supply rejection (+PSRR)
Power supply rejection (−PSRR)
VS+ = 5.5 V to 4.5 V, VS− = 0 V
VS+ = 5 V, VS− = −0.5 V to 0.5 V
POWER-DOWN CHARACTERISTICS (THS4215 ONLY)
Enable
REF = 0 V, or VS−
Power-down voltage level
REF = VS+ or floating
Power down
Power-down quiescent current
PD = Ref +1.0 V,
Ref = 0 V
450
650
750
850
µA
Max
Power-down quiescent current
PD = Ref −1.5 V,
Ref = 5 V
400
650
750
850
µA
Max
Turnon-time delay(t(ON))
50% of final value
4
µs
Typ
Turnoff-time delay (t(Off))
50% of final value
3
µns
Typ
6
GΩ
Typ
75
kΩ
Typ
Input impedance
Output impedance
6
f = 1 MHz
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
TYPICAL CHARACTERISTICS
Table of Graphs (±5 V)
FIGURE
Small-signal unity gain frequency response
1
Small-signal frequency response
2
0.1 dB gain flatness frequency response
3
Large-signal frequency response
4
Slew rate vs Output voltage
5
Harmonic distortion vs Frequency
Harmonic distortion vs Output voltage swing
6, 7, 8, 9
10, 11, 12, 13
Third order intermodulation distortion vs Frequency
14, 16
Third order output intercept point vs Frequency
15, 17
Voltage and current noise vs Frequency
18
Differential gain vs Number of loads
19
Differential phase vs Number of loads
20
Settling time
21
Quiescent current vs supply voltage
22
Output voltage vs Load resistance
23
Frequency response vs Capacitive load
24
Open-loop gain and phase vs Frequency
25
Open-loop gain vs Case temperature
26
Rejection ratios vs Frequency
27
Rejection ratios vs Case temperature
28
Common-mode rejection ratio vs Input common-mode range
29
Input offset voltage vs Case temperature
30
Input bias and offset current vs Case temperature
31
Small signal transient response
32
Large signal transient response
33
Overdrive recovery
34
Closed-loop output impedance vs Frequency
35
Power-down quiescent current vs Supply voltage
36
Power-down output impedance vs Frequency
37
Turnon and turnoff delay times
38
7
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
TYPICAL CHARACTERISTICS
Table of Graphs (5 V)
FIGURE
Small-signal unity gain frequency response
39
Small-signal frequency response
40
0.1 dB gain flatness frequency response
41
Large signal frequency response
42
Slew rate vs Output voltage
43
Harmonic distortion vs Frequency
44, 45, 46, 47
Harmonic distortion vs Output voltage swing
48, 49, 50, 51
Third order intermodulation distortion vs Frequency
52, 54
Third order intercept point vs Frequency
53, 55
Voltage and current noise vs Frequency
56
Settling time
57
Quiescent current vs Supply voltage
58
Output voltage vs Load resistance
59
Frequency response vs Capacitive load
60
Open-loop gain and phase vs Frequency
61
Open-loop gain vs Case temperature
62
Rejection ratios vs Frequency
63
Rejection ratios vs Case temperature
64
Common-mode rejection ratio vs Input common-mode range
65
Input offset voltage vs Case temperature
66
Input bias and offset current vs Case temperature
67
Small signal transient response
68
Large signal transient response
69
Overdrive recovery
70
Closed-loop output impedance vs Frequency
71
Power-down quiescent current vs Supply voltage
72
Power-down output impedance vs Frequency
73
Turnon and turnoff delay times
74
8
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
TYPICAL CHARACTERISTICS (±5 V GRAPHS)
SMALL SIGNAL UNITY GAIN
FREQUENCY RESPONSE
0.1
22
20
Gain = 1
RL = 499 Ω
VO = 250 mV
VS = ±5 V
3
2
1
0
−1
−2
0
Gain = 10
18
Small Signal Gain − dB
4
16
Small Signal Gain − dB
5
Small Signal Gain − dB
0.1 dB GAIN FLATNESS
FREQUENCY RESPONSE
SMALL SIGNAL FREQUENCY RESPONSE
Gain = 5
14
RL = 499 Ω
Rf = 392 Ω
VO = 250 mV
VS = ±5 V
12
10
8
6
Gain = 2
4
2
−4
100 k
1M
10 M
100 M
1G
Gain = −1
−2
−4
100 k
1M
10 G
f − Frequency − Hz
Figure 1
10 M
100 M
f − Frequency − Hz
−1
−2
Gain = 1
RL = 499 Ω
VO = 2 VPP
VS = ±5 V
1000
800
Fall, Gain =− 1
Rise, Gain = −1
600
400
RL = 499 Ω
Rf = 392 Ω
VS = ±5 V
0
0.5
Figure 4
1.5
2
2.5
3
3.5
4 4.5
5
1
−80
−85
−90
HARMONIC DISTORTION
vs
FREQUENCY
−80
Figure 7
100
HD2, RL = 150Ω
−90
−100
10
HD2, RL = 499Ω
−85
−100
f − Frequency − MHz
HD3, RL = 150Ω,
and RL = 499 Ω
−75
Gain = 2
Rf = 392 Ω
VO = 2 VPP
VS = ±5 V
−55
−70
−95
100
−50
−65
−95
10
Figure 6
Harmonic Distortion − dBc
Harmonic Distortion − dBc
HD2, RL = 150 Ω
1
−90
f − Frequency − MHz
Gain = 2
Rf = 392 Ω
VO = 1 VPP
VS = ±5 V
−60
HD2, RL = 499 Ω
−75
HD2, RL = 499 Ω
−85
HARMONIC DISTORTION
vs
FREQUENCY
−65
−70
HD2, RL = 150 Ω
−80
−100
−55
−60
HD3, RL = 150 Ω
and RL = 499 Ω
−75
Figure 5
HARMONIC DISTORTION
vs
FREQUENCY
Harmonic Distortion − dBc
1
−70
VO − Output Voltage − V
HD3, RL = 150 Ω
and RL = 499 Ω
1G
−95
0
1G
Gain = 1
VO = 1 VPP
VS = ±5 V
−65
200
100 M
10 M
100 M
f − Frequency − Hz
HARMONIC DISTORTION
vs
FREQUENCY
Fall, Gain = 1
f − Frequency − Hz
−55
Gain = 1
RL = 499 Ω
VO = 250 mV
VS = ±5 V
Figure 3
Harmonic Distortion − dBc
SR − Slew Rate − V/ µ s
Large Signal Gain − dB
0
Gain = 1
VO = 2 VPP
VS = ±5 V
−0.7
−60
1200
−50
−0.6
−1
1M
1G
Rise, Gain = 1
10 M
−0.5
−0.9
1400
1M
−0.4
SLEW RATE
vs
OUTPUT VOLTAGE
1
−4
100 k
−0.3
Figure 2
LARGE SIGNAL FREQUENCY RESPONSE
−3
−0.2
−0.8
0
−3
−0.1
−60
−65
−70
HD2, RL = 499Ω
−75
HD2, RL = 150Ω
−80
HD3, RL = 150Ω,
and RL = 499 Ω
−85
−90
−95
1
10
f − Frequency − MHz
Figure 8
100
−100
1
10
100
f − Frequency − MHz
Figure 9
9
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
HD3, RL = 499Ω
−85
−90
HD2, RL = 499Ω
−95
−65
HD2, RL = 499Ω
−70
HD2, RL = 150Ω
−75
−80
−85
−90
−95
0
0.5 1
1.5 2
2.5 3
3.5 4
4.5 5
0
HD3, RL = 499Ω
HD2, RL = 499Ω
−70
−75
HD2, RL = 150Ω
−85
−90
−95
−100
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Third-Order Intermodulation Distortion − dBc
0.5 1
1.5 2
−100
4.5 5
0
−55
−60
−65
−70
VO = 2 VPP
−75
−80
−85
−90
−95
VO = 1 VPP
−100
10
−55
−60
−65
−70
VO = 2 VPP
−75
−80
−85
−90
VO = 1 VPP
−95
−100
10
100
f − Frequency − MHz
Figure 16
50
45
VO = 1 VPP
40
VO = 2 VPP
35
30
0
100
20
40
60
80
Figure 15
VOLTAGE AND CURRENT NOISE
vs
FREQUENCY
100
50
45
VO = 1 VPP
40
100
f − Frequency − MHz
Gain = 2
RL = 150 Ω
VS = ±5 V
200 kHz Tone Spacing
55
4.5 5
Gain = 1
RL = 150 Ω
VS = ±5 V
200 kHz Tone Spacing
55
THIRD ORDER OUTPUT INTERCEPT
POINT
vs
FREQUENCY
Third-Order Output Intersept Point − dBm
−50
3.5 4
60
60
Gain = 2
RL = 150 Ω
VS = ±5 V
200 kHz Tone Spacing
2.5 3
THIRD ORDER OUTPUT INTERCEPT
POINT
vs
FREQUENCY
Figure 14
−40
1.5 2
Figure 12
f − Frequency − MHz
THIRD ORDER INTERMODULATION
DISTORTION
vs
FREQUENCY
−45
0.5 1
VO − Output Voltage Swing − ±V
Gain = 1
RL = 150 Ω
VS = ±5 V
200 kHz Tone Spacing
−50
Figure 13
Third-Order Intermodulation Distortion − dBc
3.5 4
−45
VO − Output Voltage Swing − ±V
10
2.5 3
100
Hz
Harmonic Distortion − dBc
HD3, RL = 150Ω
−80
HD2, RL = 150Ω
−95
THIRD ORDER INTERMODULATION
DISTORTION
vs
FREQUENCY
−60
−65
HD3, RL = 499Ω
−90
Figure 11
−40
−55
−85
VO − Output Voltage Swing − ±V
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
−50
HD3, RL = 150Ω
−80
HD3, RL = 499Ω
Figure 10
Gain = 2
Rf = 249 Ω
f = 32 MHz
VS = ±5 V
HD2, RL = 499Ω
−100
VO − Output Voltage Swing − ±V
−45
−75
Vn − Voltage Noise − nV/
−100
Gain = 2
Rf = 249 Ω
f = 8 MHz
VS = ±5 V
−70
Hz
HD2, RL = 150Ω
−60
HD3, RL = 150Ω
Vn
10
35
VO = 2 VPP
30
10
In
25
1
20
0
20
40
60
f − Frequency − MHz
Figure 17
80
100
1k
10 k
100 k
1M
f − Frequency − Hz
Figure 18
10 M
1
100 M
I n − Current Noise − pA/
−80
−65
Gain = 1
f= 32 MHz
VS = ±5 V
−55
HD3, RL = 150Ω
Third-Order Output Intersept Point − dBm
−75
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
Harmonic Distortion − dBc
−50
Gain = 1
f= 8 MHz
VS = ±5 V
Harmonic Distortion − dBc
Harmonic Distortion − dBc
−70
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
DIFFERENTIAL GAIN
vs
NUMBER OF LOADS
DIFFERENTIAL PHASE
vs
NUMBER OF LOADS
0.030
0.015
°
Differential Phase −
0.020
Gain = 2
Rf = 392 Ω
VS = ±5 V
40 IRE − NTSC and Pal
Worst Case ±100 IRE Ramp
0.18
PAL
NTSC
0.010
0.16
0.14
2
VO − Output Voltage − V
Gain = 2
Rf = 392 Ω
VS = ±5 V
40 IRE − NTSC and Pal
Worst Case ±100 IRE Ramp
0.025
Differential Gain − %
SETTLING TIME
3
0.20
0.12
0.10
PAL
0.08
0.06
NTSC
0.04
0.005
Rising Edge
1
−1
Gain = −1
RL = 499 Ω
Rf = 392 Ω
f= 1 MHz
VS = ±5 V
−2
Falling Edge
0
0.02
0
1
2
3
4
5
6
7
0
8
0
Number of Loads − 150 Ω
1
2
5
6
7
−3
8
TA = 85°C
VO − Output Voltage − V
TA = 25°C
18
TA = −40°C
16
14
12
5
1
4
0.5
3
2
1
4
4.5
TA = −40 to 85°C
0
−1
−2
10
5
100
100
30
80
20
60
10
40
0
20
10 M
f − Frequency − Hz
Figure 25
100 M
0
1G
1M
10 M
100 M
1G
REJECTION RATIOS
vs
FREQUENCY
70
VS = ±5 V
PSRR−
60
TA = 85°C
80
75
TA = −40°C
70
65
1M
−2
Figure 24
Rejection Ratios − dB
40
Phase − °
120
R(ISO) = 25 Ω
CL = 10 pF
Capacitive Load − Hz
TA = 25°C
85
Open-Loop Gain − dB
Open-Loop Gain − dB
50
100 k
−1.5
−3
100 k
1000
90
160
140
R(ISO) = 15 Ω
CL = 50 pF
−1
OPEN-LOOP GAIN
vs
CASE TEMPERATURE
60
−10
10 k
−0.5
Figure 23
OPEN-LOOP GAIN AND PHASE
vs
FREQUENCY
70
VS =±5 V
R(ISO) = 10 Ω
CL = 100 pF
0
RL − Load Resistance − Ω
180
25
−2.5
Figure 22
VS = ±5 V
20
−3
VS − Supply Voltage − ±V
80
15
FREQUENCY RESPONSE
vs
CAPACITIVE LOAD
−5
3.5
10
Figure 21
−4
10
3
5
t − Time − ns
OUTPUT VOLTAGE
vs
LOAD RESISTANCE
22
2.5
0
Figure 20
QUIESCENT CURRENT
vs
SUPPLY VOLTAGE
Quiescent Current − mA
4
Number of Loads − 150 Ω
Figure 19
20
3
Normalized Gain − dB
0
50
CMRR
40
30
PSRR+
20
10
60
2.5
3
3.5
4
Case Temperature − °C
Figure 26
4.5
5
0
100 k
1M
10 M
100 M
1G
f − Frequency − Hz
Figure 27
11
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
REJECTION RATIOS
vs
CASE TEMPERATURE
COMMON-MODE REJECTION RATIO
vs
INPUT COMMON-MODE RANGE
PSRR−
50
CMMR
PSRR+
40
30
20
10
0
−40−30−20−10 0 10 20 30 40 50 60 70 80 90
8
50
45
40
35
30
25
20
15
10
VS = ±5 V
TA = 25°C
5
0
−4.5
Case Temperature − °C
−3
−1.5
Figure 28
0.65
6.4
6.3
0.6
0.55
IIB−
0.5
6.2
IOS
6.1
0.4
6
5.9
0.45
0.35
IIB+
5.8
0.3
5.7
0.25
5.6
VO − Output Voltage − V
VS = ±5 V
1
TC − Case Temperature − °C
Figure 30
LARGE SIGNAL TRANSIENT RESPONSE
1
0.04
0.02
0
−0.02
Gain = −1
RL = 499 Ω
Rf =392 Ω
tr/tf = 300 ps
VS = ±5 V
−0.04
−0.06
−0.12
−1
0
1
2
3 4 5 6
t − Time − ns
0.5
0
−1
7
8
9
−1.5
−2 0
10
4
2
3
1.5
2
1
1
0.5
0
0
−1
−0.5
−2
−1
−3
−1.5
−4
−2
−5
−2.5
−6
−3
1
Closed-Loop Output Impedance − Ω
2.5
10 k
1k
10
1
0.1
1M
10 M
100 M
f − Frequency − Hz
Figure 35
6
8 10 12 14 16 18 20
POWER-DOWN QUIESCENT CURRENT
vs
SUPPLY VOLTAGE
800
RL = 499 Ω,
RF = 392 Ω,
PIN = −4 dBm
VS = ±5 V
100
0.01
100 k
4
Figure 33
100 k
3
2
t − Time − ns
CLOSED-LOOP OUTPUT IMPEDANCE
vs
FREQUENCY
VS = ±5 V
Gain = −1
RL = 499 Ω
Rf = 392 Ω
tr/tf = 300 ps
VS = ±5 V
−0.5
Figure 32
VI − Input Voltage − V
Single-Ended Output Voltage − V
12
2
0
−40−30−20−10 0 10 20 30 40 50 60 70 80 90
4.5
0.06
−0.1
OVERDRIVE RECOVERY
Figure 34
3
0.08
Figure 31
t − Time − µs
VS = 5 V
4
1.5
−0.08
0.2
−40−30−20−10 0 10 20 30 40 50 60 70 80 90
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
5
0.12
0.1
TC − Case Temperature − °C
6
5
3
SMALL SIGNAL TRANSIENT RESPONSE
0.7
I OS − Input Offset Current − µ A
I IB − Input Bias Current − µ A
6.5
1.5
VS = ±5 V
6
Figure 29
INPUT BIAS AND OFFSET CURRENT
vs
CASE TEMPERATURE
6.6
0
7
Input Common-Mode Range − V
VO − Output Voltage − V
Rejection Ratios − dB
60
9
55
Power-Down Quiescent Current − µ A
70
60
VOS − Input Offset Voltage − mV
VS = ±5 V
CMRR − Common-Mode Rejection Ratio − dB
80
INPUT OFFSET VOLTAGE
vs
CASE TEMPERATURE
1G
TA = 85°C
700
600
500
TA = 25°C
400
TA = −40°C
300
200
100
0
2.5
3
3.5
4
4.5
VS − Supply Voltage − ±V
Figure 36
5
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
0.1
10 M
100 M
f − Frequency − Hz
Figure 37
1G
4.5
0.03
10
1M
6
0.035
10 G
3
1.5
0.025
0.02
0
0.015
Gain = −1
RL = 499 Ω
VS = ±5 V
0.01
−3
−4.5
0.005
−6
0
−0.005
−0.01
−1.5
V I − Input Voltage Level − V
0.04
Gain = 1
RL = 499 Ω
PIN = −1 dBm
VS = ±5 V
1000
0.001
100 k
TURNON AND TURNOFF TIMES DELAY TIME
VO − Output Voltage Level − V
Power-Down Output Impedance − Ω
POWER-DOWN OUTPUT IMPEDANCE
vs
FREQUENCY
−7.5
0
0.01 0.02 0.03 0.04 0.05 0.06 0.07
t − Time − ns
Figure 38
13
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
TYPICAL CHARACTERISTICS (5 V GRAPHS)
SMALL SIGNAL UNITY GAIN
FREQUENCY RESPONSE
4
22
1
0
−1
−2
1M
10 M
100 M
1G
16
Gain = 5
14
RL = 499 Ω
Rf = 392 Ω
VO = 250 mV
VS = 5 V
12
10
8
6
Gain = 2
4
2
0
Gain = −1
−2
−4
100 k
1M
−3
−4
100 k
10 G
f − Frequency − Hz
Figure 39
−1
−2
Gain = 1
RL = 499 Ω
VO = 2 VPP
VS = 5 V
10 M
100 M
f − Frequency − Hz
−1
1M
1G
800
Rise, G = 1
600
Rise, G = −1
500
Fall, G = −1
400
300
RL = 499 Ω
Rf = 392 Ω
VS = 5 V
0.4
−65
HD2
−75
−80
Figure 45
HD3
−85
−90
0.8
1
1.2 1.4 1.6
VO − Output Voltage −V
1.8
2
1
HD2
−70
100
HD3
−80
Gain = 2
VO = 1 VPP
Rf = 392 Ω
RL = 150 Ω and 499 Ω
VS = 5 V
1
10
f − Frequency − MHz
Figure 46
100
HARMONIC DISTORTION
vs
FREQUENCY
−40
−60
10
f − Frequency − MHz
Figure 44
−50
−100
−90
f − Frequency − MHz
−80
−30
−90
10
HD2
−75
−40
−85
1
0.6
Harmonic Distortion − dBc
Harmonic Distortion − dBc
HD3
−70
−70
HARMONIC DISTORTION
vs
FREQUENCY
Gain = 1
VO = 2 VPP
RL = 150 Ω, and 499 Ω
VS = 5 V
−60
−65
Figure 43
HARMONIC DISTORTION
vs
FREQUENCY
−55
−60
−100
Figure 42
−50
Gain = 1
VO = 1 VPP
RL = 150 Ω, and 499 Ω
VS = 5 V
−95
0
−40
1G
HARMONIC DISTORTION
vs
FREQUENCY
700
100
1G
10 M
100 M
f − Frequency − Hz
Figure 41
−55
200
100 M
Gain = 1
RL = 499 Ω
VO = 250 mV
VS = 5 V
−0.7
−50
f − Frequency − Hz
−45
−0.6
−0.9
Harmonic Distortion − dBc
SR − Slew Rate − V/ µ s
Large Signal Gain − dB
0
10 M
−0.5
Fall, G = 1
900
1M
−0.4
−0.8
1000
−4
100 K
−0.3
SLEW RATE
vs
OUTPUT VOLTAGE
1
−3
−0.2
Figure 40
LARGE SIGNAL FREQUENCY RESPONSE
Harmonic Distortion − dBc
0
−0.1
Gain = 10
18
Small Signal Gain − dB
Small Signal Gain − dB
2
0.1
20
Small Signal Gain − dB
Gain = 1
RL = 499 Ω
VO = 250 mV
VS = 5 V
3
14
0.1 dB GAIN FLATNESS
FREQUENCY RESPONSE
SMALL SIGNAL FREQUENCY RESPONSE
100
−50
HD2
HD3
−60
−70
Gain = 2
VO = 2 VPP
Rf = 392 Ω
RL = 150 Ω and 499 Ω
VS = 5 V
−80
−90
1
10
f − Frequency − MHz
Figure 47
100
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
−45
−50
−65
−50
−55
−75
HD3
−80
−85
Gain = 1
RL = 150 Ω, and 499 Ω,
f = 8 MHz
VS = 5 V
0.5
1
1.5
2
VO − Output Voltage Swing − V
HD3
−70
−75
Gain = 1
RL = 150 Ω, and 499 Ω,
f = 32 MHz
VS = 5 V
−80
−85
−90
0.5
1
1.5
2
VO − Output Voltage Swing − V
Figure 48
−50
−55
HD3
−60
Gain = 2
Rf = 392 Ω
RL = 150 Ω and 499 Ω
f = 32 MHz
VS = 5 V
−75
−80
0.5
1
1.5
2
2.5
0
−50
−55
−60
−65
VO = 2VPP
−70
−75
−80
−85
VO = 1VPP
−90
−95
−100
VO = 1VPP
VO = 2VPP
35
30
0
10
VO = 1 VPP
−90
−100
10
100
f − Frequency − MHz
20
30
40
50
60
35
VO = 1 VPP
30
80
Figure 53
VOLTAGE AND CURRENT NOISE
vs
FREQUENCY
100
40
70
f − Frequency − MHz
Gain = 2
RL = 150 Ω
VS = 5 V
200 kHz Tone Spacing
45
2.5
40
THIRD ORDER OUTPUT INTERCEPT
POINT
vs
FREQUENCY
Third-Order Output Intersept Point − dBm
VO = 2 VPP
2
Gain = 1
RL = 150 Ω
VS = 5 V
200 kHz Tone Spacing
45
100
50
−60
1.5
50
Figure 52
Gain = 1
RL = 150 Ω
VS = 5 V
200 kHz Tone
Spacing
Figure 54
1
THIRD ORDER OUTPUT INTERCEPT
POINT
vs
FREQUENCY
f − Frequency − MHz
−30
−80
0.5
VO − Output Voltage Swing − V
Figure 50
10
THIRD ORDER INTERMODULATION
DISTORTION
vs
FREQUENCY
−70
2.5
Gain = 1
RL = 150 Ω
VS = 5 V
200 kHz Tone
Spacing
−45
Figure 51
−50
−95
−40
VO − Output Voltage Swing − V
−40
−90
100
Hz
0
Third-Order Intermodulation Distortion − dBc
Harmonic Distortion − dBc
HD2
−70
Gain = 2
Rf = 392 Ω
RL = 150 Ω and 499 Ω
f = 8 MHz
VS = 5 V
−85
THIRD ORDER INTERMODULATION
DISTORTION
vs
FREQUENCY
−40
−65
−80
Figure 49
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
−45
−75
−100
0
2.5
HD3
−70
Vn − Voltage Noise − nV/
0
−65
−65
Hz
−100
−60
HD2
−60
Third-Order Output Intersept Point − dBm
−90
HD2
Vn
10
VO = 2 VPP
25
20
10
In
I n − Current Noise − pA/
−70
−55
Harmonic Distortion − dBc
HD2
−95
Third-Order Intermodulation Distortion − dBc
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
−60
Harmonic Distortion − dBc
Harmonic Distortion − dBc
HARMONIC DISTORTION
vs
OUTPUT VOLTAGE SWING
15
1
10
0
20
40
60
f − Frequency − MHz
Figure 55
80
100
1k
10 k
100 k
1M
10 M
1
100 M
f − Frequency − Hz
Figure 56
15
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
QUIESCENT CURRENT
vs
SUPPLY VOLTAGE
SETTLING TIME
1.5
OUTPUT VOLTAGE
vs
LOAD RESISTANCE
22
2
Rising Edge
TA = 85°C
20
Gain = −1
RL = 499 Ω
Rf = 392 Ω
f= 1 MHz
VS = 5 V
0
−0.5
Falling Edge
−1
TA = 25°C
18
VO − Output Voltage − V
0.5
Quiescent Current − mA
VO − Output Voltage − V
1
1.5
TA = −40°C
16
14
1
0.5
TA = −40 to 85°C
0
−0.5
−1
12
−1.5
−1.5
10
10
15
t − Time − ns
20
25
−2
2.5
3
Open-Loop Gain − dB
R(ISO) = 15 Ω
CL = 50 pF
R(ISO) = 10 Ω
CL = 100 pF
60
140
50
120
40
100
30
80
20
60
10
40
0
20
1M
10 M
100 M
1G
−10
10 k
100 k
1M
80
75
TA = −40°C
70
PSRR−
Rejection Ratios − dB
70
CMRR
40
30
PSRR+
10
60
50
PSRR+
CMMR
40
30
20
10
1M
10 M
100 M
f − Frequency − Hz
Figure 63
60
2.5
1G
0
−40−30−20−10 0 10 20 30 40 50 60 70 80 90
Case Temperature − °C
Figure 64
3
3.5
4
4.5
5
Case Temperature − °C
Figure 62
VS = 5 V
PSRR−
20
0
1G
80
VS = 5 V
50
100 M
REJECTION RATIOS
vs
CASE TEMPERATURE
70
60
10 M
Figure 61
REJECTION RATIOS
vs
FREQUENCY
Rejection Ratios − dB
TA = 85°C
f − Frequency − Hz
Figure 60
16
TA = 25°C
85
65
VS = 5 V
Capacitive Load − Hz
0
100 k
1000
90
160
COMMON-MODE REJECTION RATIO
vs
INPUT COMMON-MODE RANGE
CMRR − Common-Mode Rejection Ratio − dB
Normalized Gain − dB
−3
100 k
100
RL − Load Resistance − Ω
OPEN-LOOP GAIN
vs
CASE TEMPERATURE
180
VS = 5 V
70
R(ISO) = 25 Ω, CL = 10 pF
−2
−2.5
10
Figure 59
80
0
−1.5
5
OPEN-LOOP GAIN AND PHASE
vs
FREQUENCY
1
−1
4.5
Figure 58
FREQUENCY RESPONSE
vs
CAPACITIVE LOAD
−0.5
4
VS − Supply Voltage − ±V
Figure 57
0.5
3.5
Phase − °
5
Open-Loop Gain − dB
0
60
VS = 5 V
55
50
45
40
35
30
25
20
15
10
5
0
0
1
2
3
4
5
Input Common-Mode Voltage Range − V
Figure 65
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
INPUT BIAS AND OFFSET CURRENT
vs
CASE TEMPERATURE
8
6.5
6
5
VS = 5 V
4
3
2
0.65
6.4
0.6
IIB−
6.3
0.55
6.2
0.5
6.1
0.45
IIB+
6
0.4
5.9
0.35
IOS
5.8
0.3
1
5.7
0
−40−30−20−10 0 10 20 30 40 50 60 70 80 90
0.2
5.6
−40−30−20−10 0 10 20 30 40 50 60 70 80 90
0.12
0.1
0
Gain = −1
RL = 499 Ω
Rf = 392 Ω
tr/tf = 300 ps
VS = 5 V
1.5
2
1
1
0.5
0
0
−0.5
−2
−1
−3
−1.5
0
8 10 12 14 16 18 20
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
1
500
TA = 25°C
TA = −40°C
300
200
100
0
3
3.5
4
4.5
VS − Supply Voltage − ±V
5
7
8
9
10
100
10
1
0.1
1M
10 M
100 M
f − Frequency − Hz
1G
Figure 71
0.035
Gain = 1
RL = 499 Ω
PIN = −1 dBm
VS = 5 V
0.1
1M
10 M
100 M
f − Frequency − Hz
Figure 73
1G
3
0.025
10
0.001
100 k
4.5
0.03
VO − Output Voltage Level − V
600
3 4 5 6
t − Time − ns
POWER-DOWN OUTPUT IMPEDANCE
vs
FREQUENCY
TURNON AND TURNOFF TIMES DELAY TIME
Power-Down Output Impedance − Ω
Power-Down Quiescent Current − µ A
TA = 85°C
2
RL = 499 Ω,
RF = 392 Ω,
PIN = −4 dBm
VS = 5 V
0.01
100 k
1000
800
Figure 72
1k
Figure 70
POWER-DOWN QUIESCENT CURRENT
vs
SUPPLY VOLTAGE
2.5
10 k
t − Time − µs
Figure 69
1
100 k
−1
t − Time − ns
400
0
CLOSED-LOOP OUTPUT IMPEDANCE
vs
FREQUENCY
VI − Input Voltage − V
0.5
700
−0.06
−0.1
OVERDRIVE RECOVERY
Single-Ended Output Voltage − V
VO − Output Voltage − V
1
6
Gain = −1
RL = 499 Ω
Rf =392 Ω
tr/tf = 300 ps
VS = 5 V
−0.04
−0.12
−1
VS = 5 V
4
−0.02
Figure 68
3
1.5
2
0.02
0
Figure 67
LARGE SIGNAL TRANSIENT RESPONSE
−1.5
−2 0
0.04
TC − Case Temperature − °C
Figure 66
−1
0.06
−0.08
0.25
TC − Case Temperature − °C
−0.5
0.08
10 G
1.5
0
0.02
0.015
−1.5
−3
0.01
0.005
0
−0.005
−0.01 0
Gain = −1
RL = 499 Ω
VS = 5 V
V I − Input Voltage Level − V
VS = ±5 V
VS = 5 V
Closed-Loop Output Impedance − Ω
7
SMALL SIGNAL TRANSIENT RESPONSE
0.7
VO − Output Voltage − V
6.6
I OS − Input Offset Current − µ A
9
I IB − Input Bias Current − µ A
VOS − Input Offset Voltage − mV
INPUT OFFSET VOLTAGE
vs
CASE TEMPERATURE
−4.5
−6
−7.5
0.01 0.02 0.03 0.04 0.05 0.06 0.07
t − Time − ns
Figure 74
17
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
APPLICATION INFORMATION
HIGH-SPEED OPERATIONAL AMPLIFIERS
The THS4211 and the THS4215 operational amplifiers set
new performance levels, combining low distortion, high
slew rates, low noise, and a unity-gain bandwidth in
excess of 1 GHz. To achieve the full performance of the
amplifier, careful attention must be paid to printed-circuit
board layout and component selection.
The THS4215 provides a power-down mode, providing the
ability to save power when the amplifier is inactive. A
reference pin is provided to allow the user the flexibility to
control the threshold levels of the power-down control pin.
Applications Section Contents
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
Wideband, Noninverting Operation
Wideband, Inverting Gain Operation
Single Supply Operation
Saving Power With Power-Down Functionality and
Setting Threshold Levels With the Reference Pin
Power Supply Decoupling Techniques and
Recommendations
Using the THS4211 as a DAC Output Buffer
Driving an ADC With the THS4211
Active Filtering With the THS4211
Building a Low-Noise Receiver With the THS4211
Linearity: Definitions, Terminology, Circuit
Techniques and Design Tradeoffs
An Abbreviated Analysis of Noise in Amplifiers
Driving Capacitive Loads
Printed-Circuit Board Layout Techniques for Optimal
Performance
Power Dissipation and Thermal Considerations
Performance vs Package Options
Evaluation Fixtures, Spice Models, and Applications
Support
Additional Reference Material
Mechanical Package Drawings
WIDEBAND, NONINVERTING OPERATION
The THS4211 and the THS4215 are unity gain stable
1-GHz voltage feedback operational amplifiers, with and
without power-down capability, designed to operate from
a single 5-V to 15-V power supply.
Figure 75 is the noninverting gain configuration of 2 V/V
used to demonstrate the typical performance curves. Most
of the curves were characterized using signal sources with
18
50-Ω source impedance, and with measurement
equipment presenting a 50-Ω load impedance. In
Figure 75, the 49.9-Ω shunt resistor at the VIN terminal
matches the source impedance of the test generator. The
total 499-Ω load at the output, combined with the 784-Ω
total feedback network load, presents the THS4211 and
THS4215 with an effective output load of 305 Ω for the
circuit of Figure 75.
Voltage feedback amplifiers, unlike current feedback
designs, can use a wide range of resistors values to set
their gain with minimal impact on their stability and
frequency response. Larger-valued resistors decrease the
loading effect of the feedback network on the output of the
amplifier, but this enhancement comes at the expense of
additional noise and potentially lower bandwidth.
Feedback resistor values between 392 Ω and 1 kΩ are
recommended for most situations.
5 V +V
S
+
100 pF
50 Ω Source
0.1 µF 6.8 µF
+
VI
VO
THS4211
49.9 Ω
_
Rf
392 Ω
499 Ω
392 Ω
Rg
0.1 µF 6.8 µF
100 pF
−5 V
+
−VS
Figure 75. Wideband, Noninverting Gain
Configuration
WIDEBAND, INVERTING GAIN OPERATION
Since the THS4211 and THS4215 are general-purpose,
wideband voltage-feedback amplifiers, several familiar
operational amplifier applications circuits are available to
the designer. Figure 76 shows a typical inverting
configuration where the input and output impedances and
noise gain from Figure 75 are retained in an inverting
circuit configuration. Inverting operation is one of the more
common requirements and offers several performance
benefits. The inverting configuration shows improved slew
rates and distortion due to the pseudo-static voltage
maintained on the inverting input.
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
5 V +V
S
+
100 pF
0.1 µF
6.8 µF
+
RT
200 Ω
CT
0.1 µF
50 Ω Source
VI
VO
THS4211
_
499 Ω
Rg
Rf
392 Ω
RM
57.6 Ω
392 Ω
0.1 µF
100 pF
−5 V
The last major consideration in inverting amplifier design
is setting the bias current cancellation resistor on the
noninverting input. If the resistance is set equal to the total
dc resistance looking out of the inverting terminal, the
output dc error, due to the input bias currents, is reduced
to (input offset current) multiplied by Rf in Figure 76, the dc
source impedance looking out of the inverting terminal is
392 Ω || (392 Ω + 26.8 Ω) = 200 Ω. To reduce the additional
high-frequency noise introduced by the resistor at the
noninverting input, and power-supply feedback, RT is
bypassed with a capacitor to ground.
6.8 µF
+
−VS
Figure 76. Wideband, Inverting Gain
Configuration
In the inverting configuration, some key design
considerations must be noted. One is that the gain resistor
(Rg) becomes part of the signal channel input impedance.
If the input impedance matching is desired (which is
beneficial whenever the signal is coupled through a cable,
twisted pair, long PC board trace, or other transmission
line conductors), Rg may be set equal to the required
termination value and Rf adjusted to give the desired gain.
However, care must be taken when dealing with low
inverting gains, as the resultant feedback resistor value
can present a significant load to the amplifier output. For
an inverting gain of 2, setting Rg to 49.9 Ω for input
matching eliminates the need for RM but requires a 100-Ω
feedback resistor. This has an advantage of the noise gain
becoming equal to 2 for a 50-Ω source impedance—the
same as the noninverting circuit in Figure 75. However, the
amplifier output now sees the 100-Ω feedback resistor in
parallel with the external load. To eliminate this excessive
loading, it is preferable to increase both Rg and Rf, values,
as shown in Figure 76, and then achieve the input
matching impedance with a third resistor (RM) to ground.
The total input impedance becomes the parallel
combination of Rg and RM.
The next major consideration is that the signal source
impedance becomes part of the noise gain equation and
hence influences the bandwidth. For example, the RM
value combines in parallel with the external 50-Ω source
impedance (at high frequencies), yielding an effective
source impedance of 50 Ω || 57.6 Ω = 26.8 Ω. This
impedance is then added in series with Rg for calculating
the noise gain. The result is 1.9 for Figure 76, as opposed
to the 1.8 if RM is eliminated. The bandwidth is lower for the
gain of –2 circuit, Figure 76, (NG=+1.9) than for the gain
of +2 circuit in Figure 75.
SINGLE SUPPLY OPERATION
The THS4211 is designed to operate from a single 5-V to
15-V power supply. When operating from a single power
supply, care must be taken to ensure the input signal and
amplifier are biased appropriately to allow for the
maximum output voltage swing. The circuits shown in
Figure 77 demonstrate methods to configure an amplifier
in a manner conducive for single supply operation.
+VS
50 Ω Source
+
VI
49.9 Ω
RT
THS4211
VO
_
499 Ω
+VS
2
Rf
Rg
392 Ω
+VS
2
392 Ω
Rf
392 Ω
50 Ω Source
VI
57.6 Ω
+VS
2
VS
Rg
392 Ω
RT
_
THS4211
+
VO
499 Ω
+VS
2
Figure 77. DC-Coupled Single Supply Operation
Saving Power With Power-Down Functionality
and Setting Threshold Levels With the Reference
Pin
The THS4215 features a power-down pin (PD) which
lowers the quiescent current from 19-mA down to 650-µA,
ideal for reducing system power.
The power-down pin of the amplifiers defaults to the
positive supply voltage in the absence of an applied
voltage, putting the amplifier in the power-on mode of
operation. To turn off the amplifier in an effort to conserve
power, the power-down pin can be driven towards the
19
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
negative rail. The threshold voltages for power-on and
power-down are relative to the supply rails and given in the
specification tables. Above the Enable Threshold Voltage,
the device is on. Below the Disable Threshold Voltage, the
device is off. Behavior in between these threshold voltages
is not specified.
Note that this power-down functionality is just that; the
amplifier consumes less power in power-down mode. The
power-down mode is not intended to provide a highimpedance output. In other words, the power-down
functionality is not intended to allow use as a 3-state bus
driver. When in power-down mode, the impedance looking
back into the output of the amplifier is dominated by the
feedback and gain setting resistors, but the output
impedance of the device itself varies depending on the
voltage applied to the outputs.
The time delays associated with turning the device on and
off are specified as the time it takes for the amplifier to
reach 50% of the nominal quiescent current. The time
delays are on the order of microseconds because the
amplifier moves in and out of the linear mode of operation
in these transitions.
Power-Down Reference Pin Operation
In addition to the power-down pin, the THS4215 also
features a reference pin (REF) which allows the user to
control the enable or disable power-down voltage levels
applied to the PD pin. Operation of the reference pin as it
relates to the power-down pin is described below.
In most split-supply applications, the reference pin will be
connected to ground. In some cases, the user may want
to connect it to the negative or positive supply rail. In either
case, the user needs to be aware of the voltage level
thresholds that apply to the power-down pin. The table
below illustrates the relationship between the reference
voltage and the power-down thresholds.
POWER-DOWN PIN VOLTAGE
REFERENCE
VOLTAGE
VS− to 0.5(VS− + VS+)
0.5(VS− + VS+) to VS+
DEVICE
DISABLED
DEVICE
ENABLED
≤ Ref + 1.0 V
≥ Ref + 1.8 V
≤ Ref – 1.5 V
≥ Ref – 1 V
The recommended mode of operation is to tie the
reference pin to mid-rail, thus setting the threshold levels
to mid-rail +1.0 V and midrail +1.8 V.
NO. OF CHANNELS
PACKAGES
Single (8-pin)
THS4215D, THS4215DGN, and
THS4215DRB
20
Power Supply Decoupling Techniques and
Recommendations
Power supply decoupling is a critical aspect of any
high-performance amplifier design process. Careful
decoupling provides higher quality ac performance (most
notably improved distortion performance). The following
guidelines ensure the highest level of performance.
1.
Place decoupling capacitors as close to the power
supply inputs as possible, with the goal of minimizing
the inductance of the path from ground to the power
supply.
2.
Placement priority should put the smallest valued
capacitors closest to the device.
3.
Use of solid power and ground planes is
recommended to reduce the inductance along power
supply return current paths, with the exception of the
areas underneath the input and output pins.
4.
Recommended values for power supply decoupling
include a bulk decoupling capacitor (6.8 to 22 µF), a
mid-range decoupling capacitor (0.1 µF) and a high
frequency decoupling capacitor (1000 pF) for each
supply. A 100 pF capacitor can be used across the
supplies as well for extremely high frequency return
currents, but often is not required.
APPLICATION CIRCUITS
Driving an Analog-to-Digital Converter With the
THS4211
The THS4211 can be used to drive high-performance
analog-to-digital converters. Two example circuits are
presented below.
The first circuit uses a wideband transformer to convert a
single-ended input signal into a differential signal. The
differential signal is then amplified and filtered by two
THS4211 amplifiers. This circuit provides low
intermodulation distortion, suppressed even-order
distortion, 14 dB of voltage gain, a 50-Ω input impedance,
and a single-pole filter at 100 MHz. For applications
without signal content at dc, this method of driving ADCs
can be very useful. Where dc information content is
required, the THS4500 family of fully differential amplifiers
may be applicable.
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
5V
3.3 V 3.3 V
392 Ω
+
VCM
100 Ω
THS4211
100 Ω
+5 V
_
50 Ω
(1:4 Ω)
Source 1:2
196 Ω
392 Ω
DAC5675
−5 V
392 Ω
14-Bit,
400 MSps
24.9 Ω
196 Ω
RF
+
14-Bit, 62 Msps
LO
−5 V
392 Ω
15 pF
196 Ω
49.9 Ω
THS4211
392 Ω
ADS5422
15 pF
_
24.9 Ω
392 Ω
Figure 80. Differential to Single-Ended
Conversion of a High-Speed DAC Output
_
THS4211
+
VCM
Figure 78. A Linear, Low Noise, High Gain
ADC Preamplifier
The second circuit depicts single-ended ADC drive. While
not recommended for optimum performance using
converters with differential inputs, satisfactory performance can sometimes be achieved with single-ended
input drive. An example circuit is shown here for reference.
50 Ω
Source
+5 V
For cases where a differential signaling path is desirable,
a pair of THS4211 amplifiers can be used as output
buffers. The circuit depicts differential drive into a mixer’s
IF inputs, coupled with additional signal gain and filtering.
THS4211
+
3.3 V 3.3 V
_
100 Ω
100 Ω
CF
1 nF
1 nF
IF+
+
VI
49.9 Ω
RT
RISO 0.1 µF
_
−5 V
16.5 Ω
Rf
392 Ω
Rg
DAC5675
THS4211
IN
68 pf
ADS807
12-Bit,
CM 53 Msps
IN
1.82 kΩ
0.1 µF
14-Bit,
400 MSps
392 Ω
100 Ω
392 Ω
392 Ω
49.9 Ω
392 Ω
49.9 Ω
RF(out)
IF−
1 nF
1 nF
_
CF
392 Ω
+
THS4211
NOTE: For best performance, high-speed ADCs should be driven
differentially. See the THS4500 family of devices for more
information.
Figure 79. Driving an ADC With a
Single-Ended Input
Using the THS4211 as a DAC Output Buffer
Two example circuits are presented here showing the
THS4211 buffering the output of a digital-to-analog
converter. The first circuit performs a differential to
single-ended conversion with the THS4211 configured as
a difference amplifier. The difference amplifier can double
as the termination mechanism for the DAC outputs as well.
Figure 81. Differential Mixer Drive Circuit Using
the DAC5675 and the THS4211
Active Filtering With the THS4211
High-frequency active filtering with the THS4211 is
achievable due to the amplifier’s high slew-rate, wide
bandwidth, and voltage feedback architecture. Several
options are available for high-pass, low-pass, bandpass,
and bandstop filters of varying orders. A simple two-pole
low pass filter is presented here as an example, with two
poles at 100 MHz.
21
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
100 Ω
3.9 pF
+
VI−
50 Ω Source
392 Ω
Rf1
5V
57.6 Ω
_
Rf2
_
392 Ω
VI
Rg2
THS4211
Rg1
49.9 Ω
THS4211
VO
+
33 pF
_
−5 V
Rg2
THS4211
100 Ω
Figure 82. A Two-Pole Active Filter With Two
Poles Between 90 MHz and 100 MHz
_
Rf1
49.9 Ω
VO
THS4211
+
49.9 Ω
+
Rf2
VI+
Figure 84. A High-Speed Instrumentation
Amplifier
ǒ
A Low-Noise Receiver With the THS4211
A combination of two THS4211 amplifiers can create a
high-speed, low-distortion, low-noise differential receiver
circuit as depicted in Figure 83. With both amplifiers
operating in the noninverting mode of operation, the circuit
presents a high load impedance to the source. The
designer has the option of controlling the impedance
through termination resistors if a matched termination
impedance is desired.
VI+
100 Ω
+
49.9 Ω
VO+
_
392 Ω
787 Ω
Ǔ
ǒ Ǔ
2R f1 ǒ
R f2
VO + 1 1 )
V i)–V i–Ǔ
2
Rg1
Rg2
100 Ω
(1)
THEORY AND GUIDELINES
Distortion Performance
The THS4211 provides excellent distortion performance
into a 150-Ω load. Relative to alternative solutions, it
provides exceptional performance into lighter loads, as
well as exceptional performance on a single 5-V supply.
Generally, until the fundamental signal reaches very high
frequency or power levels, the 2nd harmonic will dominate
the total harmonic distortion with a negligible 3rd harmonic
component. Focusing then on the 2nd harmonic,
increasing the load impedance improves distortion
directly. The total load includes the feedback network; in
the noninverting configuration (Figure 75) this is the sum
of Rf and Rg, while in the inverting configuration
(Figure 76), only Rf needs to be included in parallel with
the actual load.
392 Ω
_
VI−
100 Ω
49.9 Ω
VO−
+
Figure 83. A High Input Impedance, Low
Noise, Differential Receiver
A modification on this circuit to include a difference
amplifier turns this circuit into a high-speed instrumentation amplifier, as shown in Figure 84.
22
LINEARITY: DEFINITIONS, TERMINOLOGY,
CIRCUIT TECHNIQUES, AND DESIGN
TRADEOFFS
The THS4211 features execllent distortion performance
for monolithic operational amplifiers. This section focuses
on the fundamentals of distortion, circuit techniques for
reducing nonlinearity, and methods for equating distortion
of operational amplifiers to desired linearity specifications
in RF receiver chains.
Amplifiers are generally thought of as linear devices. The
output of an amplifier is a linearly scaled version of the
input signal applied to it. However, amplifier transfer
functions are nonlinear. Minimizing amplifier nonlinearity
is a primary design goal in many applications.
www.ti.com
SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
Intercept points are specifications long used as key design
criteria in the RF communications world as a metric for the
intermodulation distortion performance of a device in the
signal chain (e.g., amplifiers, mixers, etc.). Use of the
intercept point, rather than strictly the intermodulation
distortion, allows simpler system-level calculations.
Intercept points, like noise figures, can be easily cascaded
back and forth through a signal chain to determine the
overall receiver chain’s intermodulation distortion
performance. The relationship between intermodulation
distortion and intercept point is depicted in Figure 85 and
Figure 86.
Power
PO
PO
∆fc = fc − f1
∆fc = f2 − fc
IMD3 = PS − PO
PS
fc − 3∆f
f2
However, with an operational amplifier, the output does not
require termination as an RF amplifier would. Because
closed-loop amplifiers deliver signals to their outputs
regardless of the impedance present, it is important to
comprehend this when evaluating the intercept point of an
operational amplifier. The THS4211 yields optimum
distortion performance when loaded with 150 Ω to 1 kΩ,
very similar to the input impedance of an analog-to-digital
converter over its input frequency band.
As a result, terminating the input of the ADC to 50 Ω can
actually be detrimental to systems performance.
The discontinuity between open-loop, class-A amplifiers
and closed-loop, class-AB amplifiers becomes apparent
when comparing the intercept points of the two types of
devices. Equations 1 and 2 gives the definition of an
intercept point, relative to the intermodulation distortion.
PS
f1 fc
Due to the intercept point’s ease of use in system level
calculations for receiver chains, it has become the
specification of choice for guiding distortion-related design
decisions. Traditionally, these systems use primarily
class-A, single-ended RF amplifiers as gain blocks. These
RF amplifiers are typically designed to operate in a 50-Ω
environment. Giving intercept points in dBm implies an
associated impedance (50 Ω).
fc + 3∆f
OIP 3 + P O )
f − Frequency − MHz
ǒ
Figure 85
P O + 10 log
POUT
(dBm)
1X
ǒŤIMD2 ŤǓ where
3
Ǔ
V 2P
2RL 0.001
(2)
(3)
NOTE: PO is the output power of a single tone, RL is the load
resistance, and VP is the peak voltage for a single tone.
OIP3
NOISE ANALYSIS
PO
IMD3
IIP3
3X
PS
Figure 86
PIN
(dBm)
High slew rate, unity gain stable, voltage-feedback
operational amplifiers usually achieve their slew rate at the
expense of a higher input noise voltage. The 7 nV/√Hz
input voltage noise for the THS4211 and THS4215 is,
however, much lower than comparable amplifiers. The
input-referred voltage noise, and the two input-referred
current noise terms (4 pA/√Hz), combine to give low output
noise under a wide variety of operating conditions.
Figure 87 shows the amplifier noise analysis model with all
the noise terms included. In this model, all noise terms are
taken to be noise voltage or current density terms in either
nV/√Hz or pA/√Hz.
23
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
THS4211/THS4215
ENI
of the THS4211. Long PC board traces, unmatched
cables, and connections to multiple devices can easily
cause this value to be exceeded. Always consider this
effect carefully, and add the recommended series resistor
as close as possible to the THS4211 output pin (see Board
Layout Guidelines).
+
RS
IBN
ERS
EO
_
4kTRS
Rf
Rg
4kT
Rg
IBI
ERF
The criterion for setting this R(ISO) resistor is a maximum
bandwidth, flat frequency response at the load. For a gain
of +2, the frequency response at the output pin is already
slightly peaked without the capacitive load, requiring
relatively high values of R(ISO) to flatten the response at
the load. Increasing the noise gain also reduces the
peaking.
4kTRf
4kT = 1.6E−20J
at 290K
Figure 87. Noise Analysis Model
FREQUENCY RESPONSE
vs
CAPACITIVE LOAD
The total output shot noise voltage can be computed as the
square of all square output noise voltage contributors.
Equation 3 shows the general form for the output noise
voltage using the terms shown in Figure 87:
Ǹǒ
Ǔ
ENI 2 ) ǒIBNRSǓ ) 4kTR S NG 2 ) ǒIBIRfǓ ) 4kTRfNG
2
2
0.5
(4)
Normalized Gain − dB
EO +
1
Dividing this expression by the noise gain (NG=(1+ Rf/Rg))
gives the equivalent input-referred spot noise voltage at
the noninverting input, as shown in Equation 4:
EO +
Ǹ
E NI
2
ǒ Ǔ
2
I R
) ǒI BNRSǓ ) 4kTR S ) BI f
NG
2
4kTR f
)
NG
VS =±5 V
R(ISO) = 10 Ω
CL = 100 pF
0
−0.5
R(ISO) = 15 Ω
CL = 50 pF
−1
−1.5
R(ISO) = 25 Ω
CL = 10 pF
−2
−2.5
(5)
−3
100 k
1M
10 M
100 M
1G
Capacitive Load − Hz
Driving Capacitive Loads
One of the most demanding, and yet very common, load
conditions for an op amp is capacitive loading. Often, the
capacitive load is the input of an A/D converter, including
additional external capacitance, which may be
recommended to improve A/D linearity. A high-speed, high
open-loop gain amplifier like the THS4211 can be very
susceptible to decreased stability and closed-loop
response peaking when a capacitive load is placed directly
on the output pin. When the amplifier’s open-loop output
resistance is considered, this capacitive load introduces
an additional pole in the signal path that can decrease the
phase margin. When the primary considerations are
frequency response flatness, pulse response fidelity, or
distortion, the simplest and most effective solution is to
isolate the capacitive load from the feedback loop by
inserting a series isolation resistor between the amplifier
output and the capacitive load. This does not eliminate the
pole from the loop response, but rather shifts it and adds
a zero at a higher frequency. The additional zero acts to
cancel the phase lag from the capacitive load pole, thus
increasing the phase margin and improving stability.
The Typical Characteristics show the recommended
isolation resistor vs capacitive load and the resulting
frequency response at the load. Parasitic capacitive loads
greater than 2 pF can begin to degrade the performance
24
Figure 88. Isolation Resistor Diagram
BOARD LAYOUT
Achieving optimum performance with a high frequency
amplifier like the THS4211 requires careful attention to
board layout parasitics and external component types.
Recommendations that optimize performance include the
following:
1.
Minimize parasitic capacitance to any ac ground
for all of the signal I/O pins. Parasitic capacitance on
the output and inverting input pins can cause
instability: on the noninverting input, it can react with
the source impedance to cause unintentional band
limiting. To reduce unwanted capacitance, a window
around the signal I/O pins should be opened in all of
the ground and power planes around those pins.
Otherwise, ground and power planes should be
unbroken elsewhere on the board.
2.
Minimize the distance (< 0.25”) from the power
supply pins to high frequency 0.1-µF de-coupling
capacitors. At the device pins, the ground and power
plane layout should not be in close proximity to the
signal I/O pins. Avoid narrow power and ground traces
to minimize inductance between the pins and the
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SLOS400C − SEPTEMBER 2002 − REVISED JANUARY 2004
a long trace is required, and the 6-dB signal loss
intrinsic to a doubly-terminated transmission line is
acceptable, implement a matched impedance
transmission line using microstrip or stripline
techniques (consult an ECL design handbook for
microstrip and stripline layout techniques). A 50-Ω
environment is normally not necessary onboard, and
in fact a higher impedance environment improves
distortion as shown in the distortion versus load plots.
With a characteristic board trace impedance defined
on the basis of board material and trace dimensions,
a matching series resistor into the trace from the
output of the THS4211 is used as well as a terminating
shunt resistor at the input of the destination device.
Remember also that the terminating impedance is the
parallel combination of the shunt resistor and the input
impedance of the destination device: this total
effective impedance should be set to match the trace
impedance. If the 6-dB attenuation of a doubly
terminated transmission line is unacceptable, a long
trace can be series-terminated at the source end only.
Treat the trace as a capacitive load in this case and set
the series resistor value as shown in the plot of R(ISO)
vs capacitive load. This setting does not preserve
signal integrity or a doubly-terminated line. If the input
impedance of the destination device is low, there is
some signal attenuation due to the voltage divider
formed by the series output into the terminating
impedance.
decoupling capacitors. The power supply connections
should always be decoupled with these capacitors.
Larger (2.2-µF to 6.8-µF) decoupling capacitors,
effective at lower frequency, should also be used on
the main supply pins. These may be placed somewhat
farther from the device and may be shared among
several devices in the same area of the PC board.
3.
4.
Careful selection and placement of external
components preserves the high frequency
performance of the THS4211. Resistors should be a
very low reactance type. Surface-mount resistors
work best and allow a tighter overall layout. Metal-film
and carbon composition, axially-leaded resistors can
also provide good high frequency performance.
Again, keep their leads and PC board trace length as
short as possible. Never use wire-wound type
resistors in a high frequency application. Since the
output pin and inverting input pin are the most
sensitive to parasitic capacitance, always position the
feedback and series output resistor, if any, as close as
possible to the output pin. Other network components,
such as noninverting input-termination resistors,
should also be placed close to the package. Where
double-side component mounting is allowed, place
the feedback resistor directly under the package on
the other side of the board between the output and
inverting input pins. Even with a low parasitic
capacitance shunting the external resistors,
excessively high resistor values can create significant
time constants that can degrade performance. Good
axial metal-film or surface-mount resistors have
approximately 0.2 pF in shunt with the resistor. For
resistor values > 2.0 kΩ, this parasitic capacitance can
add a pole and/or a zero below 400 MHz that can
effect circuit operation. Keep resistor values as low as
possible, consistent with load driving considerations.
A good starting point for design is to set the Rf to
249 Ω for low-gain, noninverting applications. This
setting automatically keeps the resistor noise terms
low and minimizes the effect of their parasitic
capacitance.
Connections to other wideband devices on the
board may be made with short direct traces or
through onboard transmission lines. For short
connections, consider the trace and the input to the
next device as a lumped capacitive load. Relatively
wide traces (50 mils to 100 mils) should be used,
preferably with ground and power planes opened up
around them. Estimate the total capacitive load and
set RISO from the plot of recommended RISO vs
capacitive load. Low parasitic capacitive loads
(