19-1262; Rev 1; 5/01
Low-Voltage, Bidirectional
RF/Video Switch
The MAX4529 is a low-voltage T-switch designed for
switching RF and video signals from DC to 300MHz in
50Ω and 75Ω systems. This switch is constructed in a
“T” configuration, ensuring excellent high-frequency off
isolation of -80dB at 10MHz.
The MAX4529 can handle Rail-to-Rail® analog signals
in either direction. On-resistance (70Ω max) is flat (0.5Ω
max) over the specified signal range, using ±5V supplies. The off leakage current is less than 1nA at +25°C
and 20nA at +85°C.
This CMOS switch can operate with dual power supplies ranging from ±2.7V to ±6V or a single supply
between +2.7V and +12V. All digital inputs have
0.8V/2.4V logic thresholds, ensuring both TTL- and
CMOS-logic compatibility when using ±5V or a single
+5V supply.
____________________________Features
♦ High 50Ω Off Isolation: -80dB at 10MHz
♦ DC to 300MHz -3dB Signal Bandwidth
♦ 70Ω Signal Paths with ±5V Supplies
♦ 10Ω Signal-Path Flatness with ±5V Supplies
♦ ±2.7V to ±6V Dual Supplies
+2.7V to +12V Single Supply
♦ Low Power Consumption: 2kV ESD Protection per Method 3015.7
♦ TTL/CMOS-Compatible Inputs with
Single +5V or ±5V
Ordering Information
PART
________________________Applications
TEMP. RANGE
PINPACKAGE
SOT
TOP MARK
MAX4529CPA
0°C to +70°C
8 Plastic DIP
—
RF Switching
MAX4529CSA
0°C to +70°C
8 Narrow SO
—
Video Signal Routing
MAX4529CUA
0°C to +70°C
8 µMAX
High-Speed Data Acquisition
MAX4529CUT-T
0°C to +70°C
6 SOT23-6
Test Equipment
MAX4529C/D
0°C to +70°C
Dice*
—
MAX4529EPA
-40°C to +85°C
8 Plastic DIP
—
MAX4529ESA
-40°C to +85°C
8 Narrow SO
—
MAX4529EUA
-40°C to +85°C
8 µMAX
MAX4529EUT-T
-40°C to +85°C
6 SOT23-6
ATE Equipment
Networking
—
AAAQ
—
AAAQ
*Contact factory for dice specifications.
_______________________Pin Configurations/Functional Diagrams/Truth Table
MAX4529
N.C. 1
MAX4529
8 V+
NC 2
7 COM
GND 3
6 N.C.
IN 4
LOGIC
SWITCH
NC 1
6 COM
0
1
ON
OFF
V+ 2
5 GND
V- 3
4 IN
5 V-
SOT23-6
DIP/SO/µMAX
N.C. = NOT INTERNALLY CONNECTED
Rail-to-Rail is a registered trademark of Nippon Motorola Ltd.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
MAX4529
General Description
MAX4529
Low-Voltage, Bidirectional
RF/Video Switch
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to GND)
V+ ...........................................................................-0.3V, +13.0V
V- ............................................................................-13.0V, +0.3V
V+ to V-...................................................................-0.3V, +13.0V
All Other Pins (Note 1) ..........................(V- - 0.3V) to (V+ + 0.3V)
Continuous Current into Any Terminal..............................±10mA
Peak Current into Any Terminal
(pulsed at 1ms, 10% duty cycle)..................................±50mA
ESD per Method 3015.7 ..................................................>2000V
Continuous Power Dissipation (TA = +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ...727mW
8-Pin SO (derate 5.88mW/°C above +70°C)............... 471mW
8-Pin µMAX (derate 4.1mW/°C above +70°C) ............. 330mW
6-Pin SOT23-6 (derate 7.1mW/°C above +70°C) ........571mW
Operating Temperature Ranges
MAX4529C_ E .....................................................0°C to +70°C
MAX4529E_ E ..................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: Voltages on all other pins exceeding V+ or V- are clamped by internal diodes. Limit forward diode current to maximum
current rating.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS—Dual Supplies
(V+ = +4.5V to +5.5V, V- = -4.5V to -5.5V, VINL = 0.8V, VINH = 2.4V, VGND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical
values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
TA
MIN
TYP
(Note 2)
MAX
UNITS
ANALOG SWITCH
Analog Signal Range
VCOM, VNC
Signal-Path On-Resistance
RON
Signal-Path On-Resistance
Flatness (Note 4)
RFLAT(ON)
(Note 3)
V+ = 5V, V- = -5V,
VCOM = ±3V, ICOM = 1mA
V+ = 5V; V- = -5V; VCOM = 3V,
0V, -3V; ICOM = 1mA
C, E
V-
+25°C
C, E
70
100
+25°C
5
INC(OFF)
V+ = 5.5V, V- = -5.5V,
±
VCOM = ±4.5V, VNC = 4.5V
+25°C
-1
C, E
-20
COM Off Leakage Current
(Notes 5, 6)
ICOM(OFF)
V+ = 5.5V, V- = -5.5V,
±
VCOM = ±4.5V, VNC = 4.5V
+25°C
-1
C, E
-20
COM On Leakage Current
(Notes 5, 6)
ICOM(ON)
V+ = 5.5V, V- = -5.5V,
VCOM = ±4.5V
+25°C
-2
C, E
-40
NC Off Leakage Current
(Notes 5, 6)
V+
45
0.02
10
1
20
0.02
1
20
0.02
2
40
V
Ω
Ω
nA
nA
nA
LOGIC INPUT
IN Input Logic Threshold High
VINH
C, E
IN Input Logic Threshold Low
VINL
C, E
0.8
1.5
IN Input Current Logic High or
Low
IINH, IINL
C, E
-1
0.03
2
VIN = 0.8V or 2.4V
1.5
_______________________________________________________________________________________
2.4
V
V
1
µA
Low-Voltage, Bidirectional
RF/Video Switch
(V+ = +4.5V to +5.5V, V- = -4.5V to -5.5V, VINL = 0.8V, VINH = 2.4V, VGND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical
values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
TA
MIN
TYP
(Note 2)
MAX
UNITS
SWITCH DYNAMIC CHARACTERISTICS
Turn-On Time
tON
VCOM = ±3V, V+ = 5V, V- = -5V,
Figure 2
+25°C
Turn-Off Time
tOFF
VCOM = ±3V, V+ = 5V, V- = -5V,
Figure 2
+25°C
Q
CL = 1.0nF, VNC = 0V, RS = 0Ω,
Figure 3
+25°C
5
Charge Injection (Note 3)
NC Off Capacitance
45
C, E
75
100
37
C, E
75
100
10
ns
ns
pC
CNC(OFF)
VNC = GND, f = 1MHz, Figure 5
+25°C
6
pF
COM_ Off Capacitance
CCOM(OFF)
VCOM = 0V, f = 1MHz, Figure 5
+25°C
6
pF
COM_ On Capacitance
CCOM(ON)
VCOM = VNC = 0V, f = 1MHz,
Figure 5
+25°C
11.5
pF
Off Isolation (Note 7)
VISO
RL = 50Ω, VCOM = 1VRMS,
f = 10MHz, Figure 4
+25°C
-80
dB
-3dB Bandwidth
BW
RL = 50Ω, Figure 4
+25°C
300
MHz
VIN = 5Vp-p, f < 20kHz,
600Ω in and out
+25°C
0.004
%
Distortion
THD+N
POWER SUPPLY
Power-Supply Range
V+, V-
C, E
±2.7
-1
C, E
-10
V+ Supply Current
I+
V+ = 5.5V, VIN = 0V or V+,
V- = -5.5V
+25°C
V - Supply Current
I-
V+ = 5.5V, VIN = 0V or V+,
V- = -5.5V
+25°C
-1
C, E
-10
±6
0.05
1
10
0.05
1
10
V
µA
µA
_______________________________________________________________________________________
3
MAX4529
ELECTRICAL CHARACTERISTICS—Dual Supplies (continued)
MAX4529
Low-Voltage, Bidirectional
RF/Video Switch
ELECTRICAL CHARACTERISTICS—Single +5V Supply
(V+ = +4.5V to +5.5V, V- = 0V, VINL = 0.8V, VINH = 2.4V, VGND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
TA
MIN
TYP
(Note 2)
MAX
70
120
UNITS
ANALOG SWITCH
Analog Signal Range
(Note 3)
+25°C
V+ = 5V, VCOM = 3V,
ICOM = 1mA
+25°C
INC(OFF)
V+ = 5.5V, VCOM = 1V,
VNC = 4.5V
+25°C
-1
C, E
-20
COM Off Leakage Current
(Notes 5, 6, 8)
ICOM(OFF)
V+ = 5.5V, VCOM = 1V,
VNC = 4.5V
+25°C
-1
C, E
-20
COM On Leakage Current
(Notes 5, 6, 8)
ICOM(ON)
V+ = 5.5V; VCOM = 1V, 4.5V
Signal-Path On-Resistance
NC Off Leakage Current
(Notes 5, 6, 8)
VCOM, VNC
RON
0
V+
C, E
150
+25°C
-2
C, E
-40
0.02
1
20
0.02
1
20
0.02
2
40
V
Ω
nA
nA
nA
LOGIC INPUT
IN Input Logic Threshold High
VINH
C, E
IN Input Logic Threshold Low
VINL
C, E
0.8
1.5
IN Input Current Logic High or
Low
IINH, IINL
C, E
-1
0.03
VIN = 0.8V or 2.4V
1.5
2.4
V
V
1
µA
SWITCH DYNAMIC CHARACTERISTICS
Turn-On Time (Note 3)
tON
VCOM = 3V, V+ = 5V,
Figure 2
+25°C
Turn-Off Time (Note 3)
tOFF
VCOM = 3V, V+ = 5V,
Figure 2
+25°C
Charge Injection (Note 3)
Off-Isolation (Note 7)
Q
VISO
65
C, E
100
120
43
C, E
90
110
CL = 1.0nF, VNC = 2.5V,
RS = 0Ω, Figure 3
+25°C
1.5
RL = 50Ω, VCOM = 1VRMS,
f = 10MHz, Figure 4
+25°C
-75
10
ns
ns
pC
dB
POWER SUPPLY
Power-Supply Range
V+ Supply Current
4
V+
I+
V- = 0V
V+ = 5.5V, VIN = 0V or V+
C, E
2.7
+25°C
-1
C, E
-10
12.0
0.05
_______________________________________________________________________________________
1
10
V
µA
Low-Voltage, Bidirectional
RF/Video Switch
(V+ = +2.7V to +3.6V, V- = 0V, VINL = 0.4V, VINH = 2.4V, VGND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TA
TYP
(Note 2)
MAX
UNITS
ANALOG SWITCH
Analog Signal Range
VCOM, VNC
Signal-Path On-Resistance
(Note 3)
+25°C
0
RON
V+ = 2.7V, VCOM = 1.5V,
ICOM = 0.1mA
+25°C
VINH
(Note 3)
C, E
VINL
(Note 3)
C, E
0.4
VIN = 0.4V or 2.4V (Note 3)
C, E
-1
V+
175
V
400
C, E
Ω
500
LOGIC INPUT
IN Input Logic Threshold High
IN Input Logic Threshold Low
IN Input Current Logic High or Low
IINH, IINL
1.0
2.4
V
1
µA
1.0
V
SWITCH DYNAMIC CHARACTERISTICS
Turn-On Time
tON
VCOM = 1.5V, V+ = 2.7V,
Figure 2 (Note 3)
+25°C
Turn-Off Time
tOFF
VCOM = 1.5V, V+ = 2.7V,
Figure 2 (Note 3)
+25°C
I+
V+ = 3.6V, VIN = 0V or V+
150
300
C, E
ns
400
70
150
C, E
ns
200
POWER SUPPLY
V+ Supply Current
+25°C
-1
C, E
-10
0.05
1
µA
10
Note 2: The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column.
Note 3: Guaranteed by design.
Note 4: Resistance flatness is defined as the difference between the maximum and the minimum value of on-resistance as
measured over the specified analog signal range.
Note 5: Leakage parameters are 100% tested at the maximum rated hot temperature and guaranteed by correlation at +25°C.
Note 6: Guaranteed by design, not subject to production testing in SOT package.
Note 7: Off isolation = 20log10 (VCOM / VNC), VCOM = output, VNC = input to off switch.
Note 8: Leakage testing for single-supply operation is guaranteed by testing with dual supplies.
__________________________________________Typical Operating Characteristics
(V+ = +5V, V- = -5V, GND = 0V, TA = +25°C, packages are surface mount, unless otherwise noted.)
ON-RESISTANCE vs. VCOM
(SINGLE SUPPLY)
ON-RESISTANCE (Ω)
100
V+ = 2.7V
V+ = 3.3V
100
V+ = 5.0V
V+ = 7.5V
V+ = 3.3V
V- = -3.3V
V+ = 10.0V
10
-4
-3
-2 -1
0
1
VCOM (V)
2
3
4
5
+85°C
50
+70°C
0°C
30
-40°C
20
-55°C
V+ = 5V
V- = -5V
0
0
1
2
3
4
5
6
VCOM (V)
7
8
9
10
+25°C
40
10
10
-5
+125°C
60
V+ = 2.0V
V+ = 2.7V
V- = -2.7V
V+ = 5.0V
V- = -5.0V
70
MAX4529-03
V- = 0V
V+ = 1.2V
ON-RESISTANCE (Ω)
ON-RESISTANCE (Ω)
V+ = 1.2V
V- = -1.2V
V+ = 2.0V
V- = -2.0V
1000
MAX4529-01
1000
ON-RESISTANCE vs. VCOM AND
TEMPERATURE (DUAL SUPPLIES)
MAX4529-02
ON-RESISTANCE vs. VCOM
(DUAL SUPPLIES)
-5
-4
-3
-2
-1
0
1
2
3
4
5
VCOM (V)
_______________________________________________________________________________________
5
MAX4529
ELECTRICAL CHARACTERISTICS—Single +3V Supply
____________________________Typical Operating Characteristics (continued)
(V+ = +5V, V- = -5V, GND = 0V, TA = +25°C, packages are surface mount, unless otherwise noted.)
SUPPLY, COM, AND NC
LEAKAGE CURRENTS vs. TEMPERATURE
100,000
30
+25°C
0°C
1000
100
1
V+ = 5V
V- = 0V
V+ = 5V
V- = -5V
0.01
0
-55 -35 -15
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
5
25
45
65
85 105 125
-5
-4
-3
-2
-1
0
1
2
3
VCOM (V)
TEMPERATURE (°C)
VCOM (V)
ON-TIME vs. TEMPERATURE
OFF-TIME vs. TEMPERATURE
LOGIC-LEVEL THRESHOLD
vs. SUPPLY VOLTAGE
80
MAX4529-07
180
V+ = 3V
V- = 0V
70
80
V+ = 5V
V- = 0V
50
tOFF (ns)
V+ = 5V
V- = 0V
100
V+ = 3V
V- = 0V
60
120
40
V+ = 5V
V- = -5V
30
60
20
40
V+ = 5V
V- = -5V
20
3.0
0
-55 -35 -15
5
25
45
65
5
25
45
65
2
3
4
5
10
0
-10
-80
-90
OFF ISOLATION
-120
10
FREQUENCY (MHz)
100
-20
-30
-40
MAX4529-11
-50
-60
-70
ON PHASE
6
V+ (V)
10
THD (%)
40
30
20
ON PHASE (DEGREES)
LOSS (dB)
1
100
60
50
-30
-40
1
1.0
TOTAL HARMONIC DISTORTION
vs. FREQUENCY
MAX4529-10
ON LOSS
0.1
1.5
0
85 105 125
FREQUENCY RESPONSE
-100
-110
2.0
TEMPERATURE (°C)
TEMPERATURE (°C)
0
-10
-20
2.5
0
-55 -35 -15
85 105 125
5
0.5
10
0
4
MAX4529-09
0
V+ = 3V
V- = 0V
3
LOGIC-LEVEL THRESHOLD (V)
0
IOFF
0.1
MAX4529-08
10
6
V+ = 5V
V- = -5V
9
6
10
-55°C
140
ION
-40°C
20
160
12
I+, IQ (pC)
+70°C
40
V+ = 5V
V- = -5V
10,000
+85°C
CHARGE INJECTION vs. VCOM
15
MAX4529-05
+125°C
50
1,000,000
CURRENT (pA)
ON-RESISTANCE (Ω)
60
MAX4529-04
70
MAX4529-06
ON-RESISTANCE vs. VCOM AND
TEMPERATURE (SINGLE SUPPLY)
tON (ns)
MAX4529
Low-Voltage, Bidirectional
RF/Video Switch
1
-50
-60
1000
0.1
10
100
1k
10k
FREQUENCY (Hz)
_______________________________________________________________________________________
30k
7
8
9 10 11 12
Low-Voltage, Bidirectional
RF/Video Switch
PIN
NAME
FUNCTION*
SOT23-6
DIP/SO/µMAX
—
1, 6
N.C.
Not Internally Connected
1
2
NC
Analog Switch Normally Closed** Terminal
2
8
V+
Positive Supply-Voltage Input (analog and digital). The voltage difference between
V+ and V- should never exceed 12V.
3
5
V-
-5V Supply Input. Connect to GND for single-supply operation.
4
4
IN
Logic-Level Control Input. Logic-level voltages should never exceed V+ or V-.
5
3
GND
RF and Logic Ground. Connect to ground plane.
6
7
COM
Analog Switch Common** Terminal. Analog signal voltages should never exceed
V+ or V-.
* All pins except N.C. have ESD diodes to V- and V+.
** NC and COM pins are identical and interchangeable. Either may be considered as an input or output; signals pass equally well in
either direction.
Theory of Operation
Logic-Level Translators
The MAX4529 is constructed as a high-frequency “T”
switch, as shown in Figure 1. The logic-level input, IN,
is translated by amplifier A1 into a V+ to V- logic signal
that drives inverter A2. Amplifier A2 drives the gates of
N-channel MOSFETs N1 and N2 from V+ to V-, turning
them fully on or off. The same signal drives inverter A3
(which drives the P-channel MOSFETs P1 and P2) from
V+ to V-, turning them fully on or off, and drives the Nchannel MOSFET N3 off and on.
The logic-level threshold is determined by V+ and
GND. The voltage on GND is usually at ground potential, but it may be set to any voltage between
(V+ - 2V) and V-. When the voltage between V+ and
GND is less than 2V, the level translators become very
slow and unreliable. Normally, GND should be connected to the ground plane.
Switch On Condition
When the switch is on, MOSFETs N1, N2, P1, and P2
are on and MOSFET N3 is off. The signal path is COM to
NC, and because both N-channel and P-channel
MOSFETs act as pure resistances, it is symmetrical (i.e.,
signals may pass in either direction). The off MOSFET,
N3, has no DC conduction, but has a small amount of
capacitance to GND. The four on MOSFETs also have
capacitance to ground that, together with the series
resistance, forms a lowpass filter. All of these capaci-
NORMALLY CLOSED SWITCH CONSTRUCTION
N1
COM
D
IN
COM - NC
0
1
ON
OFF
N2
S
D
P1
S
NC
S
P2
D
S
D
V+
A1
A2
A3
D
IN
N3
S
GND
V+
VESD DIODES
ON GND, IN,
COM, AND NC
V-
Figure 1. T-Switch Construction
tances are distributed evenly along the series resistance, so they act as a transmission line rather than a
simple R-C filter. This helps to explain the exceptional
300MHz bandwidth when the switches are on.
Typical attenuation in 50Ω systems is -2dB and is reasonably flat up to 100MHz. Higher-impedance circuits
show even lower attenuation (and vice versa), but
slightly lower bandwidth due to the increased effect of
the internal and external capacitance and the switch’s
internal resistance.
_______________________________________________________________________________________
7
MAX4529
Pin Description
MAX4529
Low-Voltage, Bidirectional
RF/Video Switch
The MAX4529 is a optimized for ±5V operation. Using
lower supply voltages or a single supply increases
switching time, on-resistance (and therefore on-state
attenuation), and nonlinearity.
switched V+ and V- signals to drive the gates of the
analog switches. This drive signal is the only connection between the logic supplies and the analog supplies. All pins have ESD protection to V+ and to V-.
Switch Off Condition
Increasing V- has no effect on the logic-level thresholds, but it does increase the drive to the P-channel
switches, reducing their on-resistance. V- also sets the
negative limit of the analog signal voltage.
When the switch is off, MOSFETs N1, N2, P1, and P2
are off and MOSFET N3 is on. The signal path is
through the off-capacitances of the series MOSFETs,
but it is shunted to ground by N3. This forms a highpass filter whose exact characteristics depend on the
source and load impedances. In 50Ω systems, and
below 10MHz, the attenuation can exceed 80dB. This
value decreases with increasing frequency and
increasing circuit impedances. External capacitance
and board layout have a major role in determining overall performance.
Applications Information
Power-Supply Considerations
Overview
The MAX4529’s construction is typical of most CMOS
analog switches. It has three supply pins: V+, V-, and
GND. V+ and V- are used to drive the internal CMOS
switches and set the limits of the analog voltage on any
switch. Reverse ESD protection diodes are internally
connected between each analog signal pin and both
V+ and V-. If the voltage on any pin exceeds V+ or V-,
one of these diodes will conduct. During normal operation these reverse-biased ESD diodes leak, forming the
only current drawn from V-.
Virtually all the analog leakage current is through the
ESD diodes. Although the ESD diodes on a given signal pin are identical, and therefore fairly well balanced,
they are reverse biased differently. Each is biased by
either V+ or V- and the analog signal. This means their
leakages vary as the signal varies. The difference in the
two diode leakages from the signal path to the V+ and
V- pins constitutes the analog signal-path leakage current. All analog leakage current flows to the supply terminals, not to the other switch terminal. This explains
how both sides of a given switch can show leakage
currents of either the same or opposite polarity.
When the switch is on, there is no connection between
the analog signal paths and GND. The analog signal
paths consist of an N-channel and P-channel MOSFET
with their sources and drains paralleled and their gates
driven out of phase with V+ and V- by the logic-level
translators.
V+ and GND power the internal logic and logic-level
translators, and set the input logic thresholds. The
logic-level translators convert the logic levels to
8
The logic-level thresholds are CMOS and TTL compatible when V+ is +5V. As V+ is raised, the threshold
increases slightly; when V+ reaches +12V, the level
threshold is about 3.1V, which is above the TTL output
high-level minimum of 2.8V, but still compatible with
CMOS outputs.
Bipolar-Supply Operation
The MAX4529 operates with bipolar supplies between
±2.7V and ±6V. The V+ and V- supplies need not be
symmetrical, but their sum cannot exceed the absolute
maximum rating of 13.0V. Do not connect the
MAX4529 V+ pin to +3V and connect the logic-level
input pins to TTL logic-level signals. TTL logic-level
outputs can exceed the absolute maximum ratings,
causing damage to the part and/or external circuits.
CAUTION:
The absolute maximum V+ to V- differential
voltage is 13.0V. Typical “±6-Volt” or “12-Volt”
supplies with ±10% tolerances can be as high
as 13.2V. This voltage can damage the
MAX4529. Even ±5% tolerance supplies may
have overshoot or noise spikes that exceed
13.0V.
Single-Supply Operation
The MAX4529 operates from a single supply between
+2.7V and +12V when V- is connected to GND. All of
the bipolar precautions must be observed. Note, however, that these parts are optimized for ±5V operation,
and most AC and DC characteristics are degraded significantly when departing from ±5V. As the overall supply voltage (V+ to V-) is lowered, switching speed,
on-resistance, off isolation, and distortion are degraded
(see Typical Operating Characteristics).
Single-supply operation also limits signal levels and
interferes with grounded signals. When V- = 0V, AC signals are limited to -0.3V. Voltages below -0.3V can be
clipped by the internal ESD-protection diodes, and the
parts can be damaged if excessive current flows.
_______________________________________________________________________________________
Low-Voltage, Bidirectional
RF/Video Switch
Power Off
When power to the MAX4529 is off (i.e., V+ = 0V and V= 0V), the Absolute Maximum Ratings still apply. This
means that neither logic-level inputs on IN nor signals
on COM or NC can exceed ±0.3V. Voltages beyond
±0.3V cause the internal ESD-protection diodes to conduct, and the parts can be damaged if excessive current flows.
Grounding
DC Ground Considerations
Satisfactory high-frequency operation requires that
careful consideration be given to grounding. For most
applications, a ground plane is strongly recommended, and GND should be connected to it with
solid copper.
In systems that have separate digital and analog (signal) grounds, connect these switch GND pins to analog
ground. Preserving a good signal ground is much more
important than preserving a digital ground. Ground current is only a few nanoamps.
The logic-level input, IN, has voltage thresholds determined by V+ and GND. (V- does not influence the
logic-level threshold.) With +5V and 0V applied to V+
and GND, the threshold is about 1.6V, ensuring compatibility with TTL- and CMOS-logic drivers.
The GND pin can be connected to separate voltage
potentials if the logic-level input is not a normal logic
signal. (The GND voltage cannot exceed (V+ - 2V) or V-.)
Elevating GND reduces off isolation. Note, however,
that IN can be driven more negative than GND, as far
as V-. GND does not have to be removed from 0V when
IN is driven from bipolar sources, but the voltage on IN
should never exceed V-. GND should be separated
from 0V only if the logic-level threshold has to be
changed.
If the GND pin is not connected to 0V, it should be
bypassed to the ground plane with a surface-mount
10nF capacitor to maintain good RF grounding. DC
current in the IN and GND pins is less than 1nA, but
increases with switching frequency.
AC Ground and Bypassing
A ground plane is mandatory for satisfactory highfrequency operation. (Prototyping using hand wiring
or wire-wrap boards is strongly discouraged.) Connect
any 0V GND pins to the ground plane with solid copper. (The GND pin extends the high-frequency ground
through the package wire-frame, into the silicon itself,
thus improving isolation.) The ground plane should be
solid metal underneath the device, without interruptions. There should be no traces under the device itself.
For DIP packages, this applies to both sides of a twosided board. Failure to observe this will have a minimal
effect on the “on” characteristics of the switch at high
frequencies, but it will degrade the off isolation and
crosstalk.
V+ and V- pins should be bypassed to the ground
plane with surface-mount 10nF capacitors. For DIP
packages, they should be mounted as close as possible to the pins on the same side of the board as the
device. Do not use feedthroughs or vias for bypass
capacitors. For surface-mount packages, the pins are
so close to each other that the bypass capacitors
should be mounted on the opposite side of the board
from the device. In this case, use short feedthroughs or
vias, directly under the V+ and V- pins. Any GND pin
not connected to 0V should be similarly bypassed. If Vis 0V, connect it directly to the ground plane with solid
copper. Keep all leads short.
Signal Routing
Keep all signal leads as short as possible. Separate all
signal leads from each other and other traces with the
ground plane on both sides of the board. Where possible, use coaxial cable instead of printed circuit board
traces.
Board Layout
IC sockets degrade high-frequency performance and
should not be used if signal bandwidth exceeds 5MHz.
Surface-mount parts, having shorter internal lead
frames, provide the best high-frequency performance.
Keep all bypass capacitors close to the device, and
separate all signal leads with ground planes. Such
grounds tend to be wedge-shaped as they get closer to
the device. Use vias to connect the ground planes on
each side of the board, and place the vias in the apex of
the wedge-shaped grounds that separate signal leads.
Logic-level signal lead placement is not critical.
_______________________________________________________________________________________
9
MAX4529
Single-Supply Operation Above 5V
The MAX4529 is designed for operation from single
+5V or dual ±5V supplies. As V+ is increased above
5V, the logic-level threshold voltage increases and the
supply current increases. In addition, if the logic levels
are not driven rail-to-rail, the analog signal pins, COM
and NC, can conduct a significant DC current (up to
1mA) to the supply pins. This current can add an
unwanted DC bias to the signal. Therefore, when operating V+ above 5V, always drive the IN pin rail-to-rail.
MAX4529
Low-Voltage, Bidirectional
RF/Video Switch
______________________________________________Test Circuits/Timing Diagrams
+5V
10nF
V+
V+
NC
VIN
3V
50%
50%
0V
MAX4529
VIN
90%
VOUT
IN
VOUT
COM
GND
90%
0V
VRL = 50Ω
50Ω
tOFF
tON
10nF
-5V
V- IS CONNECTED TO GND (OV) FOR SINGLE-SUPPLY OPERATION.
Figure 2. Switching Time
10nF
+5V
V+
V+
NC
VNC = 0V
VIN
0V
MAX4529
VIN
IN
COM
GND
V-
VOUT
∆VOUT
VOUT
CL = 1000pF
50Ω
10nF
-5V
V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION.
∆VOUT IS THE MEASURED VOLTAGE DUE TO CHARGE TRANSFER
ERROR Q WHEN THE CHANNEL TURNS OFF.
Q = ∆VOUT x CL
Figure 3. Charge Injection
10
______________________________________________________________________________________
Low-Voltage, Bidirectional
RF/Video Switch
+5V 10nF
OFF ISOLATION = 20log
NETWORK
ANALYZER
0V OR V+
V+
IN
NC
50Ω
VIN
VOUT
VIN
V
ON LOSS = 20log OUT
VIN
50Ω
MAX4529
COM
GND
VOUT
V-
MEAS
REF
50Ω
50Ω
10nF -5V
MEASUREMENTS ARE STANDARDIZED AGAINST SHORT AT IC TERMINALS.
OFF ISOLATION IS MEASURED BETWEEN COM_ AND "OFF" NC TERMINAL.
ON LOSS IS MEASURED BETWEEN COM_ AND "ON" NC TERMINAL.
SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED.
V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION.
Figure 4. On Loss and Off Isolation
___________________Chip Topography
V+
10nF +5V
NC
0V OR V+
COM
V+
IN
NC
MAX4529
COM
GND
V-
1MHz
CAPACITANCE
ANALYZER
0.054"
(1.372mm)
N.C.
N.C.
10nF
-5V
GND
Figure 5. NC and COM Capacitance
V-
IN
0.038"
(0.965mm)
TRANSISTOR COUNT: 78
SUBSTRATE INTERNALLY CONNECTED TO V+
N.C. = NO CONNECTION
______________________________________________________________________________________
11
MAX4529
_________________________________Test Circuits/Timing Diagrams (continued)
________________________________________________________Package Information
6LSOT.EPS
MAX4529
Low-Voltage, Bidirectional
RF/Video Switch
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12
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Printed USA
is a registered trademark of Maxim Integrated Products.
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