LT3014
20mA, 3V to 80V
Low Dropout Micropower
Linear Regulator
DESCRIPTION
FEATURES
n
n
n
n
n
n
n
n
n
n
n
n
n
■
Wide Input Voltage Range: 3V to 80V
Low Quiescent Current: 7µA
Low Dropout Voltage: 350mV
Output Current: 20mA
LT3014HV Survives 100V Transients (2ms)
No Protection Diodes Needed
Adjustable Output from 1.22V to 60V
1µA Quiescent Current in Shutdown
Stable with 0.47µF Output Capacitor
Stable with Aluminum, Tantalum or Ceramic
Capacitors
Reverse-Battery Protection
No Reverse Current Flow from Output
Thermal Limiting
Available in 5-Lead ThinSOTTM and
8-Lead DFN Packages
n
n
n
Other features of the LT3014 include the ability to operate
with very small output capacitors. The regulators are stable
with only 0.47μF on the output while most older devices
require between 10μF and 100μF for stability. Small ceramic
capacitors can be used without the necessary addition of
ESR as is common with other regulators. Internal protection circuitry includes reverse-battery protection, current
limiting, thermal limiting and reverse current protection.
The device is available as an adjustable device with a 1.22V
reference voltage. The LT3014 regulator is available in the
5-lead ThinSOT and 8-lead DFN packages.
APPLICATIONS
n
The LT®3014 is a high voltage, micropower low dropout
linear regulator. The device is capable of supplying 20mA of
output current with a dropout voltage of 350mV. Designed
for use in battery-powered or high voltage systems, the low
quiescent current (7μA operating and 1μA in shutdown)
makes the LT3014 an ideal choice. Quiescent current is
also well controlled in dropout.
Low Current High Voltage Regulators
Regulator for Battery-Powered Systems
Telecom Applications
Automotive Applications
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6118263, 6144250.
TYPICAL APPLICATION
5V Supply with Shutdown
Dropout Voltage
400
VIN
5.4V TO
80V
OUT
LT3014
3.92M
VOUT
5V
20mA
0.47μF
1μF
SHDN
GND
ADJ
1.27M
3014 TA01
VSHDN OUTPUT
2.0V
ON
350
DROPOUT VOLTAGE (mV)
IN
300
250
200
150
100
50
0
0
2
4
6 8 10 12 14 16 18 20
OUTPUT CURRENT (mA)
3014 TA02
3014fd
1
LT3014
ABSOLUTE MAXIMUM RATINGS
(Note 1)
IN Pin Voltage, Operating ................................... ±80V
Transient (2ms Survival, LT3014HV) ................ +100V
OUT Pin Voltage ................................................. ±60V
IN to OUT Differential Voltage ............................ ±80V
ADJ Pin Voltage ................................................... ±7V
SHDN Pin Input Voltage ..................................... ±80V
Output Short-Circuit Duration ......................Indefinite
Storage Temperature Range
ThinSOT Package .......................... –65°C to 150°C
DFN Package ..................................–65°C to 125°C
Operating Junction Temperature Range
(Notes 3, 10, 11) ............................–40°C to 125°C
Lead Temperature
(Soldering, 10 sec, SOT-23 Package) ............300°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
IN 1
5 OUT
GND 2
SHDN 3
4 ADJ
S5 PACKAGE
5-LEAD PLASTIC SOT-23
OUT
1
8
IN
ADJ
2
7
NC
NC
3
6
NC
GND
4
5
SHDN
9
DD PACKAGE
8-LEAD (3mm s 3mm) PLASTIC DFN
EXPOSED PAD IS GND (PIN 9) MUST BE SOLDERED TO PCB
TJMAX = 125°C, θJA = 150°C/ W
θJC = 25°C/W MEASURED AT PIN 2
SEE APPLICATIONS INFORMATION SECTION
TJMAX = 125°C, θJA = 40°C/ W
θJC = 10°C/W MEASURED AT PIN 9
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3014ES5#PBF
LT3014ES5#TRPBF
LTBMF
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014IS5#PBF
LT3014IS5#TRPBF
LTBMF
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014HVES5#PBF
LT3014HVES5#TRPBF
LTBRS
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014HVIS5#PBF
LT3014HVIS5#TRPBF
LTBRS
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014EDD#PBF
LT3014EDD#TRPBF
LBMG
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT3014IDD#PBF
LT3014IDD#TRPBF
LBMG
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT3014HVEDD#PBF
LT3014HVEDD#TRPBF
LBRT
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT3014HVIDD#PBF
LT3014HVIDD#TRPBF
LBRT
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LEAD BASED FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3014ES5
LT3014ES5#TR
LTBMF
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014IS5
LT3014IS5#TR
LTBMF
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014HVES5
LT3014HVES5#TR
LTBRS
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014HVIS5
LT3014HVIS5#TR
LTBRS
5-Lead Plastic SOT-23
–40°C to 125°C
LT3014EDD
LT3014EDD#TR
LBMG
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT3014IDD
LT3014IDD#TR
LBMG
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT3014HVEDD
LT3014HVEDD#TR
LBRT
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT3014HVIDD
LT3014HVIDD#TR
LBRT
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
3014fd
2
LT3014
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TJ = 25°C.
SYMBOL
CONDITIONS
ILOAD = 20mA
VIN = 3.3V, ILOAD = 100μA
3.3V < VIN < 80V, 100μA < ILOAD < 20mA
l
Line Regulation
ΔVIN = 3.3V to 80V, ILOAD = 100μA (Note 2)
l
Load Regulation (Note 2)
VIN = 3.3V, ΔILOAD = 100μA to 20mA
VIN = 3.3V, ΔILOAD = 100μA to 20mA
l
Dropout Voltage
VIN = VOUT(NOMINAL) (Notes 4, 5)
ILOAD = 100μA
ILOAD = 100μA
l
ILOAD = 1mA
ILOAD = 1mA
l
ILOAD = 10mA
ILOAD = 10mA
l
ILOAD = 20mA
ILOAD = 20mA
l
ILOAD = 0mA
ILOAD = 100μA
ILOAD = 1mA
ILOAD = 10mA
ILOAD = 20mA
l
l
l
l
l
Output Voltage Noise
COUT = 0.47μF, ILOAD = 20mA, BW = 10Hz to 100kHz
ADJ Pin Bias Current
(Note 7)
Shutdown Threshold
VOUT = Off to On
VOUT = On to Off
l
l
SHDN Pin Current (Note 8)
VSHDN = 0V
VSHDN = 6V
l
l
Quiescent Current in Shutdown
VIN = 6V, VSHDN = 0V
l
Ripple Rejection
VIN = 7V (Avg), VRIPPLE = 0.5VP-P , fRIPPLE = 120Hz,
ILOAD = 20mA
Current Limit
VIN = 7V, VOUT = 0V
VIN = 3.3V, ΔVOUT = –0.1V (Note 2)
l
Input Reverse Leakage Current
VIN = –80V, VOUT = 0V
l
Reverse Output Current (Note 9)
VOUT = 1.22V, VIN < 1.22V (Note 2)
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LT3014 is tested and specified for these conditions with the
ADJ pin connected to the OUT pin.
Note 3: Operating conditions are limited by maximum junction
temperature. The regulated output voltage specification will not apply
for all possible combinations of input voltage and output current. When
operating at maximum input voltage, the output current range must be
limited. When operating at maximum output current, the input voltage
range must be limited.
Note 4: To satisfy requirements for minimum input voltage, the LT3014 is
tested and specified for these conditions with an external resistor divider
(249k bottom, 392k top) for an output voltage of 3.3V. The external
resistor divider adds a 5µA DC load on the output.
TYP
3
3.3
V
1.200
1.180
1.220
1.220
1.240
1.260
V
V
l
Minimum Input Voltage
ADJ Pin Voltage
(Notes 2, 3)
GND Pin Current
VIN = VOUT(NOMINAL) (Notes 4, 6)
MIN
MAX
1
10
mV
13
25
40
mV
mV
120
180
250
mV
mV
200
270
360
mV
mV
300
350
450
mV
mV
350
410
570
mV
mV
7
12
40
250
650
20
30
100
450
1000
μA
μA
μA
μA
μA
115
0.25
60
UNITS
μVRMS
4
10
nA
1.3
1.3
2
V
V
1
0
4
1
μA
μA
1
4
μA
70
dB
70
mA
mA
25
2
6
mA
4
μA
Note 5: Dropout voltage is the minimum input to output voltage differential
needed to maintain regulation at a specified output current. In dropout, the
output voltage is equal to (VIN – VDROPOUT).
Note 6: GND pin current is tested with VIN = VOUT (nominal) and a current
source load. This means the device is tested while operating in its dropout
region. This is the worst-case GND pin current. The GND pin current
decreases slightly at higher input voltages.
Note 7: ADJ pin bias current flows into the ADJ pin.
Note 8: SHDN pin current flows out of the SHDN pin.
Note 9: Reverse output current is tested with the IN pin grounded and the
OUT pin forced to the rated output voltage. This current flows into the OUT
pin and out of the GND pin.
Note 10: The LT3014 is tested and specified under pulse load conditions
such that TJ ≅ TA. The LT3014E is 100% tested at TA = 25°C. Performance
at –40°C to 125°C is assured by design, characterization, and statistical
3014fd
3
LT3014
ELECTRICAL CHARACTERISTICS
process controls. The LT3014I is guaranteed over the full –40°C to 125°C
operating junction temperature.
Note 11: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
TYPICAL PERFORMANCE CHARACTERISTICS
Typical Dropout Voltage
Guaranteed Dropout Voltage
600
500
Dropout Voltage
500
= TEST POINTS
450
500
TJ = 125oC
350
300
TJ = 25oC
250
200
150
100
TJ b 125oC
DROPOUT VOLTAGE (mV)
400
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
450
400
TJ b 25oC
300
200
0
2
4
0
6 8 10 12 14 16 18 20
OUTPUT CURRENT (mA)
IL = 1mA
200
150
2
4
IL = 100MA
0
–50
6 8 10 12 14 16 18 20
OUTPUT CURRENT (mA)
VIN = 6V
RL = d
IL = 0
VSHDN = VIN
8
6
4
2
0
–50 –25
Quiescent Current
IL = 100μA
TJ = 25oC
14 RL = d
VOUT = 1.22V
VSHDN = 0V
75
50
25
TEMPERATURE (oC)
0
100
125
3014 G04
QUIESCENT CURRENT (μA)
10
125
100
16
1.235
12
50
25
0
75
TEMPERATURE (oC)
–25
3014 G03
ADJ Pin Voltage
1.240
ADJ PIN VOLTAGE (V)
QUIESCENT CURRENT (μA)
250
3014 G02
Quiescent Current
14
IL = 10mA
300
50
0
3014 G01
16
IL = 20mA
350
100
100
50
0
400
1.230
1.225
1.220
1.215
1.210
12
10
8
6
4
1.205
2
1.200
–50 –25
0
75
50
25
TEMPERATURE (oC)
0
100
125
3014 G05
VSHDN = VIN
VSHDN = 0V
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
3014 G06
3014fd
4
LT3014
TYPICAL PERFORMANCE CHARACTERISTICS
GND Pin Current
VIN = 3.3V
900 TJ = 25oC
= 1.22V
V
800 OUT
RL = 617
IL = 20mA*
500
400
RL = 1227
IL = 10mA*
300
200
RL = 1.22k
IL = 1mA*
100
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
700
600
500
400
300
1.6
1.4
1.2
1.0
0.8
0.6
200
0.4
100
0.2
0
10
1.8
SHDN PIN THRESHOLD (V)
GND PIN CURRENT (μA)
GND PIN CURRENT (μA)
800
600
2.0
1000
TJ = 25oC
900 *FOR VOUT = 1.22V
700
SHDN Pin Threshold
GND Pin Current vs ILOAD
1000
2
0
4
0
–50
6 8 10 12 14 16 18 20
OUTPUT CURRENT (mA)
–25
0
25
50
75
TEMPERATURE (oC)
100
125
3014 G09
3014 G07
3014 G08
SHDN Pin Current
SHDN Pin Current
TJ = 25oC
CURRENT FLOWS
1.0 OUT OF SHDN PIN
14
VSHDN = 0V
1.4 CURRENT FLOWS
OUT OF SHDN PIN
0.8
0.6
0.4
0.2
12
ADJ PIN BIAS CURRENT (nA)
SHDN PIN CURRENT (μA)
SHDN PIN CURRENT (μA)
ADJ Pin Bias Current
1.6
1.2
1.2
1.0
0.8
0.6
0.4
0
2.5 3
1 1.5 2
SHDN PIN VOLTAGE (V)
0.5
3.5
0
–50 –25
4
75
50
25
TEMPERATURE (oC)
0
100
VOUT = 0V
70 TJ = 25oC
90
CURRENT LIMIT (mA)
CURRENT LIMIT (mA)
50
40
30
20
VIN = 7V
VOUT = 0V
70
60
50
40
30
10
0
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
3014 G13
0
–50
100
125
Reverse Output Current
20
10
50
75
25
TEMPERATURE (oC)
50
80
60
0
3014 G12
Current Limit
100
4
4
0
–50 –25
125
REVERSE OUTPUT CURRENT (μA)
Current Limit
80
2
6
3014 G11
3014 G10
0
8
2
0.2
0
10
TJ = 25oC
45 VIN = 0V
= VADJ
V
40 OUT
ADJ PIN
ESD CLAMP
35
30
25
20
CURRENT FLOWS
INTO OUTPUT PIN
15
10
5
–25
50
25
0
75
TEMPERATURE (oC)
100
125
3014 G14
0
0
1
2
3 4 5 6 7 8
OUTPUT VOLTAGE (V)
9
10
3014 G15
3014fd
5
LT3014
TYPICAL PERFORMANCE CHARACTERISTICS
Reverse Output Current
REVERSE OUTPUT CURRENT (μA)
7
Input Ripple Rejection
Input Ripple Rejection
72
VIN = 0V
VOUT = VADJ = 1.22V
RIPPLE REJECTION (dB)
6
5
4
3
2
80
VIN = 7V + 0.5VP-P
70 RIPPLE AT f = 120Hz
IL = 20mA
68
66
64
62
60
58
1
0
–50 –25
75
50
25
TEMPERATURE (oC)
0
100
75
50
25
TEMPERATURE (oC)
100
0
–5
LOAD REGULATION (mV)
MINIMUM INPUT VOLTAGE (V)
ILOAD = 20mA
2.5
2.0
1.5
1.0
0.5
20
100
COUT = 0.47μF
100
100k
1M
3014 G18
$IL = 100μA TO 20mA
VOUT = 1.22V
–10
–15
–20
–25
–30
125
–40
–50 –25
0
25
50
75
100
125
10
COUT = 0.47μF
IL = 20mA
VOUT = 1.22V
1
0.1
0.01
10
100
TEMPERATURE (oC)
3014 G19
1k
10k
FREQUENCY (Hz)
100k
3014 G21
3014 G20
Transient Response
VOUT
200μV/DIV
3014 G22
LOAD CURRENT (mA)
OUTPUT VOLTAGE
DEVIATION (V)
10Hz to 100kHz Output Noise
1ms/DIV
1k
10k
FREQUENCY (Hz)
Output Noise Spectral Density
–35
25
75
0
50
TEMPERATURE (oC)
COUT = 4.7μF
30
Load Regulation
0
3.0
COUT = 0.47μF
IL = 200mA
VOUT = 1.22V
40
0
10
125
OUTPUT NOISE SPECTRAL DENSITY (MV/Hz)
Minimum Input Voltage
0
–50 –25
50
3014 G17
3014 G16
3.5
60
10
56
–50 –25
125
VIN = 7V + 50mVRMS RIPPLE
IL = 20mA
70
RIPPLE REJECTION (dB)
8
0.04
0.02
0
VIN = 7V
VOUT = 5V
CIN = COUT = 0.47μF CERAMIC
$ILOAD = 1mA TO 5mA
–0.02
–0.04
6
4
2
0
0
200
600
400
TIME (μs)
800
1000
3014 G23
3014fd
6
LT3014
PIN FUNCTIONS
(SOT-23 Package/DD Package)
IN (Pin 1/Pin 8): Input. Power is supplied to the device
through the IN pin. A bypass capacitor is required on this
pin if the device is more than six inches away from the main
input filter capacitor. In general, the output impedance of
a battery rises with frequency, so it is advisable to include
a bypass capacitor in battery-powered circuits. A bypass
capacitor in the range of 0.1μF to 10μF is sufficient. The
LT3014 is designed to withstand reverse voltages on the IN
pin with respect to ground and the OUT pin. In the case of
a reversed input, which can happen if a battery is plugged
in backwards, the LT3014 will act as if there is a diode in
series with its input. There will be no reverse current flow
into the LT3014 and no reverse voltage will appear at the
load. The device will protect both itself and the load.
GND (Pin 2/Pins 4, 9): Ground.
SHDN (Pin 3/Pin 5): Shutdown. The SHDN pin is used
to put the LT3014 into a low power shutdown state. The
output will be off when the SHDN pin is pulled low. The
SHDN pin can be driven either by 5V logic or open-collector
logic with a pull-up resistor. The pull-up resistor is only
required to supply the pull-up current of the open-collector gate, normally several microamperes. If unused, the
SHDN pin must be tied to IN or to a logic high.
ADJ (Pin 4/Pin 2): Adjust. This is the input to the error
amplifier. This pin is internally clamped to ±7V. It has a
bias current of 4nA which flows into the pin (see curve
of ADJ Pin Bias Current vs Temperature in the Typical
Performance Characteristics). The ADJ pin voltage is
1.22V referenced to ground, and the output voltage range
is 1.22V to 60V.
OUT (Pin 5/Pin 1): Output. The output supplies power to
the load. A minimum output capacitor of 0.47μF is required
to prevent oscillations. Larger output capacitors will be
required for applications with large transient loads to limit
peak voltage transients. See the Applications Information
section for more information on output capacitance and
reverse output characteristics.
3014fd
7
LT3014
APPLICATIONS INFORMATION
The LT3014 is a 20mA high voltage low dropout regulator
with micropower quiescent current and shutdown. The
device is capable of supplying 20mA at a dropout voltage
of 350mV. The low operating quiescent current (7μA) drops
to 1μA in shutdown. In addition to the low quiescent current, the LT3014 incorporates several protection features
which make it ideal for use in battery-powered systems.
The device is protected against both reverse input and
reverse output voltages. In battery backup applications
where the output can be held up by a backup battery
when the input is pulled to ground, the LT3014 acts like it
has a diode in series with its output and prevents reverse
current flow.
Adjustable Operation
The LT3014 has an output voltage range of 1.22V to 60V.
The output voltage is set by the ratio of two external
resistors as shown in Figure 1. The device servos the
output to maintain the voltage at the adjust pin at 1.22V
referenced to ground. The current in R1 is then equal to
1.22V/R1 and the current in R2 is the current in R1 plus
the ADJ pin bias current. The ADJ pin bias current, 4nA
at 25°C, flows through R2 into the ADJ pin. The output
voltage can be calculated using the formula in Figure 1.
The value of R1 should be less than 1.62M to minimize
errors in the output voltage caused by the ADJ pin bias
current. Note that in shutdown the output is turned off
and the divider current will be zero. The device is tested
and specified with the ADJ pin tied to the OUT pin and a
5μA DC load (unless otherwise specified) for an output
voltage of 1.22V. Specifications for output voltages greater
than 1.22V will be proportional to the ratio of the desired
output voltage to 1.22V (VOUT/1.22V). For example, load
regulation for an output current change of 1mA to 20mA
IN
VIN
VOUT
OUT
R2
LT3014
+
ADJ
GND
R1
3014 F01
VOUT = 1.22V • 1 + R2 + (IADJ)(R2)
R1
VADJ = 1.22V
IADJ = 4nA AT 25oC
OUTPUT RANGE = 1.22V TO 60V
Figure 1. Adjustable Operation
is –13mV typical at VOUT = 1.22V. At VOUT = 12V, load
regulation is:
(12V/1.22V) • (–13mV) = –128mV
Output Capacitance and Transient Response
The LT3014 is designed to be stable with a wide range of
output capacitors. The ESR of the output capacitor affects
stability, most notably with small capacitors. A minimum
output capacitor of 0.47μF with an ESR of 3Ω or less is
recommended to prevent oscillations. The LT3014 is a
micropower device and output transient response will be
a function of output capacitance. Larger values of output
capacitance decrease the peak deviations and provide
improved transient response for larger load current
changes. Bypass capacitors, used to decouple individual
components powered by the LT3014, will increase the
effective output capacitor value.
Extra consideration must be given to the use of ceramic
capacitors. Ceramic capacitors are manufactured with a
variety of dielectrics, each with different behavior across
temperature and applied voltage. The most common
dielectrics used are specified with EIA temperature characteristic codes of Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitances
in a small package, but they tend to have strong voltage
and temperature coefficients as shown in Figures 2 and 3.
When used with a 5V regulator, a 16V 10μF Y5V capacitor
can exhibit an effective value as low as 1μF to 2μF for the
DC bias voltage applied and over the operating temperature range. The X5R and X7R dielectrics result in more
stable characteristics and are more suitable for use as the
output capacitor. The X7R type has better stability across
temperature, while the X5R is less expensive and is available in higher values. Care still must be exercised when
using X5R and X7R capacitors; the X5R and X7R codes
only specify operating temperature range and maximum
capacitance change over temperature. Capacitance change
due to DC bias with X5R and X7R capacitors is better than
Y5V and Z5U capacitors, but can still be significant enough
to drop capacitor values below appropriate levels. Capacitor DC bias characteristics tend to improve as component
case size increases, but expected capacitance at operating
voltage should be verified.
3014fd
8
LT3014
APPLICATIONS INFORMATION
Voltage and temperature coefficients are not the only
sources of problems. Some ceramic capacitors have a
piezoelectric response. A piezoelectric device generates
voltage across its terminals due to mechanical stress, similar to the way a piezoelectric accelerometer or microphone
works. For a ceramic capacitor the stress can be induced
by vibrations in the system or thermal transients.
20
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
CHANGE IN VALUE (%)
0
X5R
For surface mount devices, heat sinking is accomplished
by using the heat spreading capabilities of the PC board
and its copper traces. Copper board stiffeners and plated
through-holes can also be used to spread the heat generated by power devices.
The following table lists thermal resistance for several
different board sizes and copper areas. All measurements
were taken in still air on 3/32” FR-4 board with one ounce
copper.
Table 1. SOT-23 Measured Thermal Resistance
–20
COPPER AREA
–40
–60
Y5V
–80
–100
BOARD AREA
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)
2500 sq mm 2500 sq mm
2500 sq mm
125°C/W
1000 sq mm 2500 sq mm
2500 sq mm
125°C/W
225 sq mm
2500 sq mm
2500 sq mm
130°C/W
100 sq mm
2500 sq mm
2500 sq mm
135°C/W
50 sq mm
2500 sq mm
2500 sq mm
150°C/W
TOPSIDE
0
2
4
8
6
10 12
DC BIAS VOLTAGE (V)
14
16
BACKSIDE
3014 F02
Thermal Considerations
The power handling capability of the device will be limited
by the maximum rated junction temperature (125°C). The
power dissipated by the device will be made up of two
components:
1. Output current multiplied by the input/output voltage
differential: IOUT • (VIN – VOUT) and,
2. GND pin current multiplied by the input voltage:
IGND • VIN.
The GND pin current can be found by examining the GND
Pin Current curves in the Typical Performance Characteristics. Power dissipation will be equal to the sum of the
two components listed above.
The LT3014 regulator has internal thermal limiting designed to protect the device during overload conditions.
For continuous normal conditions the maximum junction
temperature rating of 125°C must not be exceeded. It is
important to give careful consideration to all sources of
thermal resistance from junction to ambient. Additional
heat sources mounted nearby must also be considered.
Table 2. DFN Measured Thermal Resistance
COPPER AREA
BOARD AREA
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)
2500 sq mm 2500 sq mm
2500 sq mm
40°C/W
1000 sq mm 2500 sq mm
2500 sq mm
45°C/W
225 sq mm
2500 sq mm
2500 sq mm
50°C/W
100 sq mm
2500 sq mm
2500 sq mm
62°C/W
TOPSIDE
BACKSIDE
For the DFN package, the thermal resistance junction-tocase (θJC), measured at the Exposed Pad on the back of
the die, is 16°C/W.
40
20
CHANGE IN VALUE (%)
Figure 2. Ceramic Capacitor DC Bias Characteristics
0
X5R
–20
–40
Y5V
–60
–80
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
–100
50
25
75
–50 –25
0
TEMPERATURE (oC)
100
125
3014 F03
Figure 3. Ceramic Capacitor Temperature Characteristics
3014fd
9
LT3014
APPLICATIONS INFORMATION
Continuous operation at large input/output voltage differentials and maximum load current is not practical
due to thermal limitations. Transient operation at high
input/output differentials is possible. The approximate
thermal time constant for a 2500sq mm 3/32" FR-4 board
with maximum topside and backside area for one ounce
copper is 3 seconds. This time constant will increase as
more thermal mass is added (i.e. vias, larger board, and
other components).
For an application with transient high power peaks, average
power dissipation can be used for junction temperature
calculations as long as the pulse period is significantly less
than the thermal time constant of the device and board.
Calculating Junction Temperature
Example 1: Given an output voltage of 5V, an input voltage range of 24V to 30V, an output current range of 0mA
to 20mA, and a maximum ambient temperature of 50°C,
what will the maximum junction temperature be?
The power dissipated by the device will be equal to:
IOUT(MAX) • (VIN(MAX) – VOUT) + (IGND • VIN(MAX))
where:
IOUT(MAX) = 20mA
VIN(MAX) = 30V
IGND at (IOUT = 20mA, VIN = 30V) = 0.55mA
So:
P = 20mA • (30V – 5V) + (0.55mA • 30V) = 0.52W
The thermal resistance for the DFN package will be in the
range of 40°C/W to 62°C/W depending on the copper
area. So the junction temperature rise above ambient will
be approximately equal to:
0.52W • 50°C/W = 26°C
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
TJMAX = 50°C + 26°C = 76°C
Example 2: Given an output voltage of 5V, an input voltage
of 48V that rises to 72V for 5ms(max) out of every 100ms,
and a 5mA load that steps to 20mA for 50ms out of every
250ms, what is the junction temperature rise above ambient? Using a 500ms period (well under the time constant
of the board), power dissipation is as follows:
P1(48V in, 5mA load) = 5mA • (48V – 5V)
+ (100μA • 48V) = 0.22W
P2(48V in, 20mA load) = 20mA • (48V – 5V)
+ (0.55mA • 48V) = 0.89W
P3(72V in, 5mA load) = 5mA • (72V – 5V)
+ (100μA • 72V) = 0.34W
P4(72V in, 20mA load) = 20mA • (72V – 5V)
+ (0.55mA • 72V) = 1.38W
Operation at the different power levels is as follows:
76% operation at P1, 19% for P2, 4% for P3, and
1% for P4.
PEFF = 76%(0.22W) + 19%(0.89W) + 4%(0.34W)
+ 1%(1.38W) = 0.36W
With a thermal resistance in the range of 40°C/W to
62°C/W, this translates to a junction temperature rise
above ambient of 20°C.
3014fd
10
LT3014
APPLICATIONS INFORMATION
Protection Features
The LT3014 incorporates several protection features which
make it ideal for use in battery-powered circuits. In addition to the normal protection features associated with
monolithic regulators, such as current limiting and thermal
limiting, the device is protected against reverse-input voltages, and reverse voltages from output to input.
Current limit protection and thermal overload protection
are intended to protect the device against current overload
conditions at the output of the device. For normal operation,
the junction temperature should not exceed 125°C.
The input of the device will withstand reverse voltages
of 80V. Current flow into the device will be limited to less
than 6mA (typically less than 100μA) and no negative
voltage will appear at the output. The device will protect
both itself and the load. This provides protection against
batteries which can be plugged in backward.
The ADJ pin can be pulled above or below ground by as
much as 7V without damaging the device. If the input is
left open circuit or grounded, the ADJ pin will act like an
open circuit when pulled below ground, and like a large
resistor (typically 100k) in series with a diode when pulled
above ground. If the input is powered by a voltage source,
pulling the ADJ pin below the reference voltage will cause
the device to current limit. This will cause the output to go
to an unregulated high voltage. Pulling the ADJ pin above
the reference voltage will turn off all output current.
In situations where the ADJ pin is connected to a resistor
divider that would pull the ADJ pin above its 7V clamp voltage if the output is pulled high, the ADJ pin input current
must be limited to less than 5mA. For example, a resistor
divider is used to provide a regulated 1.5V output from the
1.22V reference when the output is forced to 60V. The top
resistor of the resistor divider must be chosen to limit the
current into the ADJ pin to less than 5mA when the ADJ
pin is at 7V. The 53V difference between the OUT and ADJ
pins divided by the 5mA maximum current into the ADJ
pin yields a minimum top resistor value of 10.6k.
In circuits where a backup battery is required, several
different input/output conditions can occur. The output
voltage may be held up while the input is either pulled
to ground, pulled to some intermediate voltage, or is left
open circuit. Current flow back into the output will follow
the curve shown in Figure 4. The rise in reverse output
current above 7V occurs from the breakdown of the 7V
clamp on the ADJ pin. With a resistor divider on the
regulator output, this current will be reduced depending
on the size of the resistor divider.
When the IN pin of the LT3014 is forced below the OUT
pin or the OUT pin is pulled above the IN pin, input current will typically drop to less than 2μA. This can happen
if the input of the LT3014 is connected to a discharged
(low voltage) battery and the output is held up by either
a backup battery or a second regulator circuit. The state
of the SHDN pin will have no effect on the reverse output
current when the output is pulled above the input.
REVERSE OUTPUT CURRENT (μA)
50
TJ = 25oC
45 VIN = 0V
= VADJ
V
40 OUT
ADJ PIN
ESD CLAMP
35
30
25
20
CURRENT FLOWS
INTO OUTPUT PIN
15
10
5
0
0
1
2
3 4 5 6 7 8
OUTPUT VOLTAGE (V)
9
10
3014 F04
Figure 4. Reverse Output Current
3014fd
11
LT3014
TYPICAL APPLICATIONS
5V Buck Converter with Low Current Keep Alive Backup
D2
D1N914
6
VIN
5.5V*
TO 60V
C2
0.33μF
BOOST
4
C3
4.7μF
100V
CERAMIC
VIN
SW
2
14
VOUT
5V
1A/20mA
D1
10MQ060N
LT1766
15
L1†
15μH
SHDN
BIAS
SYNC
FB
GND
10
R1
15.4k
12
R2
4.99k
VC
+
C1
100μF 10V
SOLID
TANTALUM
1, 8, 9, 16 11
CC
1nF
IN
LT3014
OPERATING
CURRENT
SHDN
LOW HIGH
3014 TA03
OUT
3.92M
ADJ
GND
1.27M
* FOR INPUT VOLTAGES BELOW 7.5V,
SOME RESTRICTIONS MAY APPLY
†
INCREASE L1 TO 30μH FOR LOAD
CURRENTS ABOVE 0.6A AND TO
60μH ABOVE 1A
Buck Converter
Efficiency vs Load Current
100
VOUT = 5V
L = 68μH
VIN = 10V
EFFICIENCY (%)
90
VIN = 42V
80
70
60
50
0
0.25
0.75
1.00
0.50
LOAD CURRENT (A)
1.25
3014 TA04
3014fd
12
LT3014
TYPICAL APPLICATIONS
LT3014 Automotive Application
VIN
12V
(LATER 42V)
IN
+
1μF
NO PROTECTION
DIODE NEEDED!
OUT
LT3014
R1
1μF
ADJ
SHDN
GND
R2
LOAD: CLOCK,
SECURITY SYSTEM
ETC
OFF ON
LT3014 Telecom Application
VIN
48V
(72V TRANSIENT)
IN
OUT
LT3014
1μF
ADJ
SHDN
GND
+
R1 NO PROTECTION
DIODE NEEDED!
1μF
R2
OFF ON
LOAD:
SYSTEM MONITOR
ETC
–
BACKUP
BATTERY
3014 TA05
Constant Brightness for Indicator LED over Wide Input Voltage Range
RETURN
IN
1μF
OFF ON
OUT
LT3014
SHDN
1μF
ADJ
GND
–48V
ILED = 1.22V/RSET
–48V CAN VARY FROM –3.3V TO –80V
RSET
3014 TA06
3014fd
13
LT3014
PACKAGE DESCRIPTION
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
0.62
MAX
0.95
REF
2.90 BSC
(NOTE 4)
1.22 REF
1.4 MIN
3.85 MAX 2.62 REF
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
1.90 BSC
S5 TSOT-23 0302 REV B
3014fd
14
LT3014
PACKAGE DESCRIPTION
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
0.675 p0.05
3.5 p0.05
1.65 p0.05
2.15 p0.05 (2 SIDES)
PACKAGE
OUTLINE
0.25 p 0.05
0.50
BSC
2.38 p0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
R = 0.115
TYP
5
3.00 p0.10
(4 SIDES)
0.38 p 0.10
8
1.65 p 0.10
(2 SIDES)
PIN 1
TOP MARK
(NOTE 6)
(DD) DFN 1203
0.200 REF
0.75 p0.05
0.00 – 0.05
4
0.25 p 0.05
1
0.50 BSC
2.38 p0.10
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
3014fd
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LT3014
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1129
700mA, Micropower, LDO
VIN: 4.2V to 30V, VOUT(MIN) = 3.75V, VDO = 0.4V, IQ = 50μA, ISD = 16μA,
DD, SOT-223, S8, TO220, TSSOP-20 Packages
LT1175
500mA, Micropower Negative LDO
VIN: –20V to –4.3V, VOUT(MIN) = –3.8V, VDO = 0.50V, IQ = 45μA, ISD = 10μA,
DD, SOT-223, S8 Packages
LT1185
3A, Negative LDO
VIN: –35V to –4.2V, VOUT(MIN) = –2.40V, VDO = 0.80V, IQ = 2.5mA, ISD
工商网监
湘ICP备2023018690号
