LT1962 Series
1
1962fa1962fb
For more information www.linear.com/LT1962
Typical applicaTion
DescripTion
300mA, Low Noise,
Micropower
LDO Regulators
The LT
®
1962 series are micropower, low noise, low dropout
regulators. The devices are capable of supplying 300mA
of output current with a dropout voltage of 270mV. De-
signed for use in battery-powered systems, the low 30µA
quiescent current makes them an ideal choice. Quiescent
current is well controlled; it does not rise in dropout as it
does with many other regulators.
A key feature of the LT1962 regulators is low output noise.
With the addition of an external 0.01µF bypass capacitor,
output noise drops to 20µVRMS over a 10Hz to 100kHz
bandwidth. The LT1962 regulators are stable with output
capacitors as low as 3.3µF. Small ceramic capacitors can
be used without the series resistance required by other
regulators.
Internal protection circuitry includes reverse battery protec-
tion, current limiting, thermal limiting and reverse current
protection. The parts come in fixed output voltages of 1.5V,
1.8V, 2.5V, 3V, 3.3V and 5V, and as an adjustable device
with a 1.22V reference voltage. The LT1962 regulators are
available in the 8-lead MSOP package.
L, LT, LT C, LT M, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
FeaTures
applicaTions
n Low Noise: 20µVRMS (10Hz to 100kHz)
n Output Current: 300mA
n Low Quiescent Current: 30µA
n Wide Input Voltage Range: 1.8V to 20V
n Low Dropout Voltage: 270mV
n Very Low Shutdown Current: < 1µA
n No Protection Diodes Needed
n Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3V, 3.3V, 5V
n Adjustable Output from 1.22V to 20V
n Stable with 3.3µF Output Capacitor
n Stable with Aluminum, Tantalum or
Ceramic Capacitors
n Reverse Battery Protection
n No Reverse Current
n Overcurrent and Overtemperature Protected
n 8-Lead MSOP Package
n Cellular Phones
n Battery-Powered Systems
n Noise-Sensitive Instrumentation Systems
3.3V Low Noise Regulator
Dropout Voltage
IN
SHDN
0.01µF
10µF
1962 TA01
OUT
SENSE
VIN
3.7V TO
20V
BYP
GND
LT1962-3.3
3.3V AT 300mA
20µVRMS
NOISE
1µF +
LOAD CURRENT (mA)
0
DROPOUT VOLTAGE (mV)
400
350
300
250
200
150
100
50
0
1962 TA02
100 200
300
50 150 250
LT1962 Series
2
1962fa1962fb
For more information www.linear.com/LT1962
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 3)
absoluTe MaxiMuM raTings
IN Pin Voltage .........................................................±20V
OUT Pin Voltage ......................................................±20V
Input to Output Differential Voltage (Note 2) ...........±20V
SENSE Pin Voltage ..................................................±20V
ADJ Pin Voltage ........................................................±7V
BYP Pin Voltage .....................................................±0.6V
SHDN Pin Voltage ...................................................±20V
Output Short-Circuit Duration .......................... Indefinite
Operating Junction Temperature Range
(Note 3) ............................................. –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ...................300°C
elecTrical characTerisTics
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage LT1962 ILOAD = 300mA (Notes 4, 12) l1.8 2.3 V
Regulated Output Voltage
(Notes 4, 5)
LT1962-1.5 VIN = 2V, ILOAD = 1mA
2.5V < VIN < 20V, 1mA < ILOAD < 300mA
l
1.485
1.462
1.500
1.500
1.515
1.538
V
V
LT1962-1.8 VIN = 2.3V, ILOAD = 1mA
2.8V < VIN < 20V, 1mA < ILOAD < 300mA
l
1.782
1.755
1.800
1.800
1.818
1.845
V
V
LT1962-2.5 VIN = 3V, ILOAD = 1mA
3.5V < VIN < 20V, 1mA < ILOAD < 300mA
l
2.475
2.435
2.500
2.500
2.525
2.565
V
V
LT1962-3 VIN = 3.5V, ILOAD = 1mA
4V < VIN < 20V, 1mA < ILOAD < 300mA
l
2.970
2.925
3.000
3.000
3.030
3.075
V
V
LT1962-3.3 VIN = 3.8V, ILOAD = 1mA
4.3V < VIN < 20V, 1mA < ILOAD < 300mA
l
3.267
3.220
3.300
3.300
3.333
3.380
V
V
LT1962-5 VIN = 5.5V, ILOAD = 1mA
6V < VIN < 20V, 1mA < ILOAD < 300mA
l
4.950
4.875
5.000
5.000
5.050
5.125
V
V
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT1962EMS8#PBF LT1962EMS8#TRPBF LTML 8-Lead Plastic MSOP –40°C to 125°C
LT1962IMS8#PBF LT1962IMS8#TRPBF LTML 8-Lead Plastic MSOP –40°C to 125°C
LT1962EMS8-1.5#PBF LT1962EMS8-1.5#TRPBF LTSZ 8-Lead Plastic MSOP –40°C to 125°C
LT1962EMS8-1.8#PBF LT1962EMS8-1.8#TRPBF LTTA 8-Lead Plastic MSOP –40°C to 125°C
LT1962EMS8-2.5#PBF LT1962EMS8-2.5#TRPBF LTPT 8-Lead Plastic MSOP –40°C to 125°C
LT1962EMS8-3#PBF LT1962EMS8-3#TRPBF LTPQ 8-Lead Plastic MSOP –40°C to 125°C
LT1962EMS8-3.3#PBF LT1962EMS8-3.3#TRPBF LTPS 8-Lead Plastic MSOP –40°C to 125°C
LT1962EMS8-5#PBF LT1962EMS8-5#TRPBF LTPR 8-Lead Plastic MSOP –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.
Consult LTC Marketing for information on nonstandard lead based finish parts.
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/
pin conFiguraTion
1
2
3
4
OUT
SENSE/ADJ*
BYP
GND
8
7
6
5
IN
NC
NC
SHDN
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 125°C/W
*PIN 2: SENSE FOR LT1962-1.5/LT1962-1.8/
LT1962-2.5/LT1962-3/LT1962-3.3/
LT1962-5. ADJ FOR LT1962
(Note 1)
LT1962 Series
3
1962fa1962fb
For more information www.linear.com/LT1962
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 3)
elecTrical characTerisTics
PARAMETER CONDITIONS MIN TYP MAX UNITS
ADJ Pin Voltage
(Notes 4, 5)
LT1962 VIN = 2V, ILOAD = 1mA
2.3V < VIN < 20V, 1mA < ILOAD < 300mA
l
1.208
1.190
1.220
1.220
1.232
1.250
V
V
Line Regulation LT1962-1.5 ∆VIN = 2V to 20V, ILOAD = 1mA
LT1962-1.8 ∆VIN = 2.3V to 20V, ILOAD = 1mA
LT1962-2.5 ∆VIN = 3V to 20V, ILOAD = 1mA
LT1962-3 ∆VIN = 3.5V to 20V, ILOAD = 1mA
LT1962-3.3 ∆VIN = 3.8V to 20V, ILOAD = 1mA
LT1962-5 ∆VIN = 5.5V to 20V, ILOAD = 1mA
LT1962 (Note 4) ∆VIN = 2V to 20V, ILOAD = 1mA
l
l
l
l
l
l
l
1
1
1
1
1
1
1
5
5
5
5
5
5
5
mV
mV
mV
mV
mV
mV
mV
Load Regulation LT1962-1.5 VIN = 2.5V, ∆ILOAD = 1mA to 300mA
VIN = 2.5V, ∆ILOAD = 1mA to 300mA
l
3 8
15
mV
mV
LT1962-1.8 VIN = 2.8V, ∆ILOAD = 1mA to 300mA
VIN = 2.8V, ∆ILOAD = 1mA to 300mA
l
4 9
18
mV
mV
LT1962-2.5 VIN = 3.5V, ∆ILOAD = 1mA to 300mA
VIN = 3.5V, ∆ILOAD = 1mA to 300mA
l
5 12
25
mV
mV
LT1962-3 VIN = 4V, ∆ILOAD = 1mA to 300mA
VIN = 4V, ∆ILOAD = 1mA to 300mA
l
7 15
30
mV
mV
LT1962-3.3 VIN = 4.3V, ∆ILOAD = 1mA to 300mA
VIN = 4.3V, ∆ILOAD = 1mA to 300mA
l
7 17
33
mV
mV
LT1962-5 VIN = 6V, ∆ILOAD = 1mA to 300mA
VIN = 6V, ∆ILOAD = 1mA to 300mA
l
12 25
50
mV
mV
LT1962 (Note 4) VIN = 2.3V, ∆ILOAD = 1mA to 300mA
VIN = 2.3V, ∆ILOAD = 1mA to 300mA
l
2 6
12
mV
mV
Dropout Voltage
VIN = VOUT(NOMINAL)
(Notes 6, 7, 12)
ILOAD = 10mA
ILOAD = 10mA
l
0.10 0.15
0.21
V
V
ILOAD = 50mA
ILOAD = 50mA
l
0.15 0.20
0.28
V
V
ILOAD = 100mA
ILOAD = 100mA
l
0.18 0.24
0.33
V
V
ILOAD = 300mA
ILOAD = 300mA
l
0.27 0.33
0.43
V
V
GND Pin Current
VIN = VOUT(NOMINAL)
(Notes 6, 8)
ILOAD = 0mA
ILOAD = 1mA
ILOAD = 50mA
ILOAD = 100mA
ILOAD = 300mA
l
l
l
l
l
30
65
1.1
2
8
75
120
1.6
3
12
µA
µA
mA
mA
mA
Output Voltage Noise COUT = 10µF, CBYP = 0.01µF, ILOAD = 300mA, BW = 10Hz to 100kHz 20 µVRMS
ADJ Pin Bias Current (Notes 4, 9) 30 100 nA
Shutdown Threshold VOUT = Off to On
VOUT = On to Off
l
l
0.25
0.8
0.65
2 V
V
SHDN Pin Current
(Note 10)
VSHDN = 0V
VSHDN = 20V
0.01
1
0.5
5
µA
µA
Quiescent Current in Shutdown VIN = 6V, VSHDN = 0V 0.1 1 µA
Ripple Rejection VIN – VOUT = 1.5V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz,
ILOAD = 300mA
55 65 dB
Current Limit VIN = 7V, VOUT = 0V
VIN = VOUT(NOMINAL) + 1V, ∆VOUT = –0.1V
l
320
700 mA
mA
Input Reverse Leakage Current VIN = –20V, VOUT = 0V l1 mA
LT1962 Series
4
1962fa1962fb
For more information www.linear.com/LT1962
Typical Dropout Voltage Guaranteed Dropout Voltage Dropout Voltage
OUTPUT CURRENT (mA)
0
DROPOUT VOLTAGE (mV)
150
200
250
150 250
1962 G01
100
50
050 100 200
300
350
400
300
TJ = 125°C
TJ = 25°C
OUTPUT CURRENT (mA)
0
0
GUARANTEED DROPOUT VOLTAGE (mV)
100
200
300
50 100 150 200
1962 G02
250
400
500
50
150
250
350
450
300
= TEST POINTS
TJ ≤ 125°C
TJ ≤ 25°C
TEMPERATURE (°C)
–50
DROPOUT VOTLAGE (mV)
350
25
1962 G03
200
100
–25 0 50
50
0
400
300
250
150
75 100
125
IL = 300mA
IL = 100mA
IL = 50mA
IL = 10mA
IL = 1mA
PARAMETER CONDITIONS MIN TYP MAX UNITS
Reverse Output Current
(Note 11)
LT1962-1.5 VOUT = 1.5V, VIN < 1.5V
LT1962-1.8 VOUT = 1.8V, VIN < 1.8V
LT1962-2.5 VOUT = 2.5V, VIN < 2.5V
LT1962-3 VOUT = 3V, VIN < 3V
LT1962-3.3 VOUT = 3.3V, VIN < 3.3V
LT1962-5 VOUT = 5V, VIN < 5V
LT1962 (Note 4) VOUT = 1.22V, VIN < 1.22V
10
10
10
10
10
10
5
20
20
20
20
20
20
10
µA
µA
µA
µA
µA
µA
µA
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 3)
elecTrical characTerisTics
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: Absolute maximum input to output differential voltage cannot
be achieved with all combinations of rated IN pin and OUT pin voltages.
With the IN pin at 20V, the OUT pin may not be pulled below 0V. The total
measured voltage from in to out can not exceed ±20V.
Note 3: The LT1962 is tested and specified under pulse load conditions
such that TJ ≈ TA. The LT1962E is tested at TA = 25°C and performance
is guaranteed from 0°C to 125°C. Performance of the LT1962E over the
full –40°C to 125°C operating temperature range is assured by design,
characterization, and correlation with statistical process controls. The
LT1962I is guaranteed over the full –40°C to 125°C operating junction
temperature range.
Note 4: The LT1962 (adjustable version) is tested and specified for these
conditions with the ADJ pin connected to the OUT pin.
Note 5: 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 6: To satisfy requirements for minimum input voltage, the LT1962
(adjustable version) is tested and specified for these conditions with an
external resistor divider (two 250k resistors) for an output voltage of
2.44V. The external resistor divider will add a 5µA DC load on the output.
Note 7: Dropout voltage is the minimum input to output voltage differential
needed to maintain regulation at a specified output current. In dropout, the
output voltage will be equal to: VIN – VDROPOUT.
Note 8: GND pin current is tested with VIN = VOUT(NOMINAL) or VIN = 2.3V
(whichever is greater) 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 will decrease slightly at higher input
voltages.
Note 9: ADJ pin bias current flows into the ADJ pin.
Note 10: SHDN pin current flows into the SHDN pin. This current is
included in the specification for GND pin current.
Note 11: 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 the GND pin.
Note 12: For the LT1962, LT1962-1.5 and LT1962-1.8 dropout voltage
will be limited by the minimum input voltage specification under some
output voltage/load conditions. See the curve of Minimum Input Voltage
in the Typical Performance Characteristics section. For other fixed voltage
versions of the LT1962, the minimum input voltage is limited by the
dropout voltage.
Typical perForMance characTerisTics
LT1962 Series
5
1962fa1962fb
For more information www.linear.com/LT1962
Typical perForMance characTerisTics
Quiescent Current LT1962-1.5 Output Voltage LT1962-1.8 Output Voltage
TEMPERATURE (°C)
–50
0
QUIESCENT CURRENT (µA)
5
15
20
25
50
35
050 75
1962 G04
10
40
45
30
–25 25 100
125
VIN = 6V
VSHDN = VIN
RL = ∞, IL = 0 (LT1962-1.5/-1.8
/2.5/-3/-3.3/-5)
RL = 250k, IL = 5µA (LT1962)
TEMPERATURE (°C)
–50
OUTPUT VOLTAGE (V)
125
1962 G05
050 100
–25 25 75
1.532
1.524
1.516
1.508
1.500
1.492
1.484
1.476
1.468
IL = 1mA
TEMPERATURE (°C)
–50
OUTPUT VOLTAGE (V)
125
1962 G06
050 100
–25 25 75
1.836
1.827
1.818
1.809
1.800
1.791
1.782
1.773
1.764
IL = 1mA
LT1962-2.5 Output Voltage LT1962-3 Output Voltage LT1962-3.3 Output Voltage
TEMPERATURE (°C)
–50
OUTPUT VOLTAGE (V)
2.53
25
1962 G07
2.50
2.48
–25 0 50
2.47
2.46
2.54
2.52
2.51
2.49
75 100
125
IL = 1mA
TEMPERATURE (°C)
–50
3.045
25
3.000
2.970
–25 0 50
2.955
2.940
3.030
3.015
2.985
75 100
IL = 1mA
TEMPERATURE (°C)
–50
3.345
25
3.300
3.270
–25 0 50
3.255
3.240
3.330
3.315
3.285
75 100
IL = 1mA
LT1962-5 Output Voltage LT1962 ADJ Pin Voltage LT1962-1.5 Quiescent Current
TEMPERATURE (°C)
–50
5.075
25
5.000
4.950
–25 0 50
4.925
4.900
5.050
5.025
4.975
75 100
IL = 1mA
TEMPERATURE (°C)
–50
ADJ PIN VOLTAGE (V)
1.235
25
1962 G11
1.220
1.210
–25 0 50
1.205
1.200
1.240
1.230
1.225
1.215
75 100
125
IL = 1mA
INPUT VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
800
700
600
500
400
300
200
100
08
1962 G12
246
10
71 3 5 9
TJ = 25°C
RL = ∞
VSHDN = VIN
VSHDN = 0V
LT1962 Series
6
1962fa1962fb
For more information www.linear.com/LT1962
Typical perForMance characTerisTics
LT1962-1.8 Quiescent Current LT1962-2.5 Quiescent Current LT1962-3 Quiescent Current
INPUT VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
800
700
600
500
400
300
200
100
08
1962 G13
246
10
71 3 5 9
TJ = 25°C
RL = ∞
VSHDN = VIN
VSHDN = 0V
INPUT VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
800
700
600
500
400
300
200
100
08
1962 G14
246
10
71 3 5 9
TJ = 25°C
RL = ∞
VSHDN = VIN
VSHDN = 0V
INPUT VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
800
700
600
500
400
300
200
100
08
1962 G15
246
10
71 3 5 9
TJ = 25°C
RL = ∞
VSHDN = VIN
VSHDN = 0V
LT1962-1.5 GND Pin Current LT1962-1.8 GND Pin Current LT1962-2.5 GND Pin Current
LT1962-3.3 Quiescent Current LT1962-5 Quiescent Current LT1962 Quiescent Current
INPUT VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
800
700
600
500
400
300
200
100
08
1962 G16
246
10
71 3 5 9
TJ = 25°C
RL = ∞
VSHDN = VIN
VSHDN = 0V
INPUT VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
800
700
600
500
400
300
200
100
08
1962 G17
246
10
71 3 5 9
TJ = 25°C
RL = ∞
VSHDN = VIN
VSHDN = 0V
INPUT VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
40
35
30
25
20
15
10
5
016
1962 G18
4 8 12
20
142 6 10 18
TJ = 25°C
RL = 250k
VSHDN = VIN
VSHDN = 0V
INPUT VOLTAGE (V)
0
GND PIN CURRENT (µA)
500
1000
1500
250
750
1250
2 4 6 8
1962 G19
10
10 3 5 7 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 1.5V
RL = 30Ω
IL = 50mA*
RL = 150Ω
IL = 10mA*
RL = 1.5k
IL = 1mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (µA)
500
1000
1500
250
750
1250
2 4 6 8
1962 G20
10
10 3 5 7 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 1.8V
RL = 36Ω
IL = 50mA*
RL = 180Ω
IL = 10mA*
RL = 1.8k
IL = 1mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (µA)
500
1000
1500
250
750
1250
2 4 6 8
1962 G21
10
10 3 5 7 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 2.5V
RL = 50Ω
IL = 50mA*
RL = 250Ω
IL = 10mA* RL = 2.5k
IL = 1mA*
LT1962 Series
7
1962fa1962fb
For more information www.linear.com/LT1962
Typical perForMance characTerisTics
LT1962-3 GND Pin Current LT1962-3.3 GND Pin Current LT1962-5 GND Pin Current
INPUT VOLTAGE (V)
0
GND PIN CURRENT (µA)
500
1000
1500
250
750
1250
2 4 6 8
1962 G22
10
10 3 5 7 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 3V
RL = 60Ω
IL = 50mA*
RL = 300Ω
IL = 10mA* RL = 3k
IL = 1mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (µA)
500
1000
1500
250
750
1250
2 4 6 8
1962 G23
10
10 3 5 7 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 3.3V
RL = 66Ω
IL = 50mA*
RL = 330Ω
IL = 10mA*
RL = 3.3k
IL = 1mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (µA)
500
1000
1500
250
750
1250
2 4 6 8
1962 G24
10
10 3 5 7 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 5V
RL = 100Ω
IL = 50mA*
RL = 500Ω
IL = 10mA*
RL = 5k
IL = 1mA*
LT1962 GND Pin Current LT1962-1.5 GND Pin Current LT1962-1.8 GND Pin Current
INPUT VOLTAGE (V)
0
GND PIN CURRENT (µA)
500
1000
1500
250
750
1250
2 4 6 8
1962 G25
10
10 3 5 7 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 1.22V
RL = 24.4Ω
IL = 50mA*
RL = 122Ω
IL = 10mA*
RL = 1.22k
IL = 1mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (mA)
8
7
6
5
4
3
2
1
08
1962 G26
246
10
71 3 5 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 1.5V
RL = 5Ω
IL = 300mA*
RL = 7.5Ω
IL = 200mA*
RL = 15Ω
IL = 100mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (mA)
8
7
6
5
4
3
2
1
08
1962 G27
246
10
71 3 5 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 1.8V
RL = 6Ω
IL = 300mA*
RL = 9Ω
IL = 200mA*
RL = 18Ω
IL = 100mA*
LT1962-2.5 GND Pin Current LT1962-3 GND Pin Current LT1962-3.3 GND Pin Current
INPUT VOLTAGE (V)
0
GND PIN CURRENT (mA)
8
7
6
5
4
3
2
1
08
1962 G28
246
10
71 3 5 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 2.5V
RL = 8.33Ω
IL = 300mA*
RL = 12.5Ω
IL = 200mA*
RL = 25Ω
IL = 100mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (mA)
8
7
6
5
4
3
2
1
08
1962 G29
246
10
71 3 5 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 3V
RL = 10Ω
IL = 300mA*
RL = 15Ω
IL = 200mA*
RL = 30Ω
IL = 100mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (mA)
8
7
6
5
4
3
2
1
08
1962 G30
246
10
71 3 5 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 3.3V
RL = 11Ω
IL = 300mA*
RL = 16.5Ω
IL = 200mA*
RL = 33Ω
IL = 100mA*
LT1962 Series
8
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For more information www.linear.com/LT1962
Typical perForMance characTerisTics
LT1962-5 GND Pin Current LT1962 GND Pin Current GND Pin Current vs ILOAD
INPUT VOLTAGE (V)
0
GND PIN CURRENT (mA)
8
7
6
5
4
3
2
1
08
1962 G31
246
10
71 3 5 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 5V
RL = 16.7Ω
IL = 300mA*
RL = 25Ω
IL = 200mA*
RL = 50Ω
IL = 100mA*
INPUT VOLTAGE (V)
0
GND PIN CURRENT (mA)
8
7
6
5
4
3
2
1
08
1962 G32
246
10
71 3 5 9
TJ = 25°C
VIN = VSHDN
*FOR VOUT = 1.22V
RL = 4.07Ω
IL = 300mA*
RL = 6.1Ω
IL = 200mA*
RL = 12.2Ω
IL = 100mA*
OUTPUT CURRENT (mA)
0
GND PIN CURRENT (mA)
3
4
5
150 250
1962 G33
2
1
050 100 200
6
7
8
300
VIN = VOUT(NOMINAL) + 1V
SHDN Pin Input Current ADJ Pin Bias Current Current Limit
SHDN Pin Threshold (On-to-Off) SHDN Pin Threshold (Off-to-On) SHDN Pin Input Current
TEMPERATURE (°C)
–50
0
SHDN PIN THRESHOLD (V)
0.1
0.3
0.4
0.5
1.0
0.7
050 75
1962 G34
0.2
0.8
0.9
0.6
–25 25 100
125
IL = 1mA
TEMPERATURE (°C)
–50
0
SHDN PIN THRESHOLD (V)
0.1
0.3
0.4
0.5
1.0
0.7
050 75
1962 G35
0.2
0.8
0.9
0.6
–25 25 100
125
IL = 1mA
IL = 300mA
SHDN PIN VOLTAGE (V)
0
0
SHDN PIN INPUT CURRENT (µA)
0.2
0.6
0.8
1.0
1.4
157
1962 G36
0.4
1.2
49
10
236 8
TEMPERATURE (°C)
–50
SHDN PIN INPUT CURRENT (µA)
1.4
25
1962 G37
0.8
0.4
–25 0 50
0.2
0
1.6
1.2
1.0
0.6
75 100
125
VSHDN = 20V
TEMPERATURE (°C)
–50
20
25
35
25 75
1962 G38
15
10
–25 0 50 100
125
5
0
30
ADJ PIN BIAS CURRENT (nA)
INPUT VOLTAGE (V)
0
0
CURRENT LIMIT (A)
0.1
0.3
0.4
0.5
1.0
0.7
245
1962 G39
0.2
0.8
0.9
0.6
136
7
VOUT = 0V
LT1962 Series
9
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Typical perForMance characTerisTics
Current Limit Reverse Output Current Reverse Output Current
TEMPERATURE (°C)
–50
CURRENT LIMIT (A)
0.8
1.0
1.2
25 75
1962 G40
0.6
0.4
–25 0 50 100
125
0.2
0
VIN = 7V
VOUT = 0V
TEMPERATURE (°C)
–50
REVERSE OUTPUT CURRENT (µA)
20
25
30
25 75
1962 G42
15
10
–25 0 50 100
125
5
0
VIN = 0V
VOUT = 1.22V (LT1962)
VOUT = 1.5V (LT1962-1.5)
VOUT = 1.8V (LT1962-1.8)
VOUT = 2.5V (LT1962-2.5)
VOUT = 3V (LT1962-3)
VOUT = 3.3V (LT1962-3.3)
VOUT = 5V (LT1962-5)
LT1962
LT1962-1.5/-1.8/-2.5/-3/-3.3/-5
OUTPUT VOLTAGE (V)
0 1
REVERSE OUTPUT CURRENT (µA)
30
40
50
60
70
80
90
100
8 97
1962 G41
20
10
02 3 46
5
10
LT1962
LT1962-5
TJ = 25°C
VIN = 0V
CURRENT FLOWS
INTO OUTPUT PIN
VOUT = VADJ (LT1962)
LT1962-1.5
LT1962-1.8
LT1962-2.5
LT1962-3
LT1962-3.3
Input Ripple Rejection Input Ripple Rejection Ripple Rejection
FREQUENCY (Hz)
20
RIPPLE REJECTION (dB)
30
50
70
80
10 1k 10k
1M
1962 G43
10
100 100k
60
40
0
IL = 300mA
VIN = VOUT(NOMINAL) + 1V
+ 50mVRMS RIPPLE
CBYP = 0
COUT = 10µF
COUT = 3.3µF
FREQUENCY (Hz)
20
RIPPLE REJECTION (dB)
30
50
70
80
10 1k 10k
1M
1962 G44
10
100 100k
60
40
0
IL = 300mA
VIN = VOUT(NOMINAL) + 1V
+ 50mVRMS RIPPLE
COUT = 10µF
CBYP = 0.01µF
CBYP = 1000pF
CBYP = 100pF
TEMPERATURE (°C)
–50
RIPPLE REJECTION (dB)
66
25
1962 G45
60
56
–25 0 50
54
52
68
64
62
58
75 100
125
IL = 300mA
VIN = VOUT(NOMINAL) + 1V
+ 0.5VP-P RIPPLE AT f = 120Hz
LT1962 Minimum Input Voltage Load Regulation Output Noise Spectral Density
TEMPERATURE (°C)
–50
0
MINIMUM INPUT VOLTAGE (V)
0.25
0.75
1.00
1.25
2.50
1.75
050 75
1962 G46
0.50
2.00
2.25
1.50
–25 25 100
125
VOUT = 1.22V
IL = 300mA
IL = 1mA
TEMPERATURE (°C)
–50
LOAD REGULATION (mV)
–5
0
5
25 75
1962 G47
–10
–15
–25 0 50 100
125
–20
–25
LT1962
LT1962-2.5
LT1962-1.8 LT1962-1.5
VIN = VOUT(NOMINAL) + 1V
∆IL = 1mA TO 300mA
LT1962-3
LT1962-3.3
LT1962-5
FREQUENCY (Hz)
0.1
OUTPUT NOISE SPECTRIAL DENSITY (µV/√Hz)
1
10 1k 10k
100k
1962 G48
0.01 100
10
LT1962 LT1962-2.5
LT1962-1.5
LT1962-5 LT1962-3.3
IL = 300mA
COUT = 10µF
CBYP = 0 LT1962-3
LT1962-1.8
LT1962 Series
10
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Typical perForMance characTerisTics
Output Noise Spectral Density
RMS Output Noise
vs Bypass Capacitor
RMS Output Noise
vs Load Current (10Hz to 100kHz)
FREQUENCY (Hz)
0.1
OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)
1
10 1k 10k
100k
1962 G49
0.01 100
10
LT1962-5
LT1962
IL = 300mA
COUT = 10µF
CBYP = 0.01µF
CBYP = 100pF
CBYP = 1000pF
CBYP (pF)
10
80
OUTPUT NOISE (µV
RMS
)
120
160
100 1k
10k
1962 G50
40
60
100
140
20
0
IL = 300mA
COUT = 10µF
f = 10Hz to 100kHz
LT1962-5
LT1962-3.3
LT1962-3
LT1962
LT1962-2.5
LT1962-1.8
LT1962-1.5
LOAD CURRENT (mA)
40
OUTPUT NOISE (µV
RMS
)
60
100
140
160
0.01 1 10
1000
1962 G51
20
0.1 100
120
80
0
COUT = 10µF
CBYP = 0µF
CBYP = 0.01µF
LT1962-5
LT1962-5
LT1962
LT1962
LT1962-5 10Hz to 100kHz
Output Noise (CBYP = 0.01µF) LT1962-5 Transient Response LT1962-5 Transient Response
LT1962-5 10Hz to 100kHz
Output Noise (CBYP = 0)
LT1962-5 10Hz to 100kHz
Output Noise (CBYP = 100pF)
LT1962-5 10Hz to 100kHz
Output Noise (CBYP = 1000pF)
TIME (ms)
0
OUTPUT VOLTAGE
DEVIATION (V)LOAD CURRENT (mA)
0
0.2
0.4
1.6
1962 G56
–0.2
–0.4
0
100
200
300
0.4
0.2 0.6 0.8 1.2 1.8
1.4
1.0
2.0
VIN = 6V
CIN = 10µF
COUT = 10µF
CBYP = 0
TIME (µs)
0
OUTPUT VOLTAGE
DEVIATION (mV)LOAD CURRENT (mA)
0
0.05
0.10
400
1962 G57
–0.05
–0.10
0
100
200
300
100
50 150 200 300 450
350
250
500
VIN = 6V
CIN = 10µF
COUT = 10µF
CBYP = 0.01µF
1ms/DIV
1962 G52
COUT = 10µF
IL = 300mA
VOUT
100µV/DIV
1ms/DIV
1962 G53
COUT = 10µF
I
L
= 300mA
VOUT
100µV/DIV
1ms/DIV
1962 G54
COUT = 10µF
IL = 300mA
VOUT
100µV/DIV
1ms/DIV
1962 G55
COUT = 10µF
I
L
= 300mA
VOUT
100µV/DIV
LT1962 Series
11
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pin FuncTions
OUT (Pin 1): Output. The output supplies power to the
load. A minimum output capacitor of 3.3µF 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.
SENSE (Pin 2): Sense. For fixed voltage versions of the
LT1962 (LT1962-1.5/LT1962-1.8/LT1962-2.5/LT1962-3/
LT1962-3.3/LT1962-5), the SENSE pin is the input to the
error amplifier. Optimum regulation will be obtained at the
point where the SENSE pin is connected to the OUT pin of
the regulator. In critical applications, small voltage drops
are caused by the resistance (RP) of PC traces between
the regulator and the load. These may be eliminated by
connecting the SENSE pin to the output at the load as
shown in Figure 1 (Kelvin Sense Connection). Note that
the voltage drop across the external PC traces will add to
the dropout voltage of the regulator. The SENSE pin bias
current is 10µA at the nominal rated output voltage. The
SENSE pin can be pulled below ground (as in a dual supply
system where the regulator load is returned to a negative
supply) and still allow the device to start and operate.
BYP (Pin 3): Bypass. The BYP pin is used to bypass the
reference of the LT1962 to achieve low noise performance
from the regulator. The BYP pin is clamped internally to
±0.6V (one VBE). A small capacitor from the output to
this pin will bypass the reference to lower the output volt-
age noise. A maximum value of 0.01µF can be used for
reducing output voltage noise to a typical 20µVRMS over
a 10Hz to 100kHz bandwidth. If not used, this pin must
be left unconnected.
GND (Pin 4): Ground.
SHDN (Pin 5): Shutdown. The SHDN pin is used to put
the LT1962 regulators 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
required to supply the pull-up current of the open-collector
gate, normally several microamperes, and the SHDN pin
current, typically 1µA. If unused, the SHDN pin must be
connected to VIN. The device will not function if the SHDN
pin is not connected.
NC (Pins 6, 7): No Connect. These pins are not internally
connected. For improved power handling capabilities,
these pins can be connected to the PC board.
IN (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 1µF to 10µF is sufficient.
The LT1962 regulators are designed to withstand reverse
voltages on the IN pin with respect to ground and the OUT
pin. In the case of a reverse input, which can happen if
a battery is plugged in backwards, the device will act as
if there is a diode in series with its input. There will be
no reverse current flow into the regulator and no reverse
voltage will appear at the load. The device will protect both
itself and the load.
Figure 1. Kelvin Sense Connection
IN
SHDN
1962 F01
R
P
OUT
V
IN
SENSE
GND
LT1962
RP
4
2
1
5
8
+
+LOAD
ADJ (Pin 2): Adjust. For the adjustable LT1962, this is the
input to the error amplifier. This pin is internally clamped
to ±7V. It has a bias current of 30nA which flows into the
pin. The ADJ pin voltage is 1.22V referenced to ground
and the output voltage range is 1.22V to 20V.
LT1962 Series
12
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applicaTions inForMaTion
The LT1962 series are 300mA low dropout regulators with
micropower quiescent current and shutdown. The devices
are capable of supplying 300mA at a dropout voltage of
300mV. Output voltage noise can be lowered to 20µVRMS
over a 10Hz to 100kHz bandwidth with the addition of a
0.01µF reference bypass capacitor. Additionally, the refer-
ence bypass capacitor will improve transient response of
the regulator, lowering the settling time for transient load
conditions. The low operating quiescent current (30µA)
drops to less than 1µA in shutdown. In addition to the
low quiescent current, the LT1962 regulators incorporate
several protection features which make them ideal for use
in battery-powered systems. The devices are 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 LT1962-X acts like it has a diode in series with
its output and prevents reverse current flow. Additionally,
in dual supply applications where the regulator load is
returned to a negative supply, the output can be pulled
below ground by as much as 20V and still allow the device
to start and operate.
Adjustable Operation
The adjustable version of the LT1962 has an output voltage
range of 1.22V to 20V. The output voltage is set by the
ratio of two external resistors as shown in Figure 2. The
device servos the output to maintain the ADJ pin voltage
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 cur-
rent, 30nA at 25°C, flows through R2 into the ADJ pin.
The output voltage can be calculated using the formula in
Figure 2. The value of R1 should be no greater than 250k
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 adjustable device is tested and specified with the ADJ
pin tied to the OUT pin 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 300mA is –2mV typical
at VOUT = 1.22V. At VOUT = 12V, load regulation is:
(12V/1.22V)(–2mV) = –19.7mV
Bypass Capacitance and Low Noise Performance
The LT1962 regulators may be used with the addition
of a bypass capacitor from VOUT to the BYP pin to lower
output voltage noise. A good quality low leakage capacitor
is recommended. This capacitor will bypass the reference
of the regulator, providing a low frequency noise pole. The
noise pole provided by this bypass capacitor will lower the
output voltage noise to as low as 20µVRMS with the addition
of a 0.01µF bypass capacitor. Using a bypass capacitor has
the added benefit of improving transient response. With no
bypass capacitor and a 10µF output capacitor, a 10mA to
300mA load step will settle to within 1% of its final value
in less than 100µs. With the addition of a 0.01µF bypass
capacitor, the output will settle to within 1% for a 10mA
to 300mA load step in less than 10µs, with total output
voltage deviation of less than 2% (see LT1962-5 Transient
Response in the Typical Performance Characteristics sec-
tion). However, regulator start-up time is proportional to
the size of the bypass capacitor, slowing to 15ms with a
0.01µF bypass capacitor and 10µF output capacitor.
Output Capacitance and T
ransient Response
The LT1962 regulators are designed to be stable with a
wide range of output capacitors. The ESR of the output
capacitor affects stability, most notably with small capaci-
tors. A minimum output capacitor of 3.3µF with an ESR
of 3Ω or less is recommended to prevent oscillations.
Figure 2. Adjustable Operation
IN
1962 F02
R2
OUT
VIN
V
OUT
ADJ
GND
LT1962
R1
+
VOUT =1.22V 1+R2
R1
⎛
⎝
⎜⎞
⎠
⎟+IADJ
( )
R2
( )
VADJ =1.22V
IADJ = 30nA at 25°C
OUTPUT RANGE = 1.22V to 20V
LT1962 Series
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applicaTions inForMaTion
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 Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitance
in a small package, but exhibit strong voltage and tem-
perature coefficients as shown in Figures 4 and 5. When
used with a 5V regulator, a 10µF Y5V capacitor can exhibit
an effective value as low as 1µF to 2µF 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.
The LT1962-X is a micropower device and output tran-
sient 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 LT1962,
will increase the effective output capacitor value. With
larger capacitors used to bypass the reference (for low
noise operation), larger values of output capacitance are
needed. For 100pF of bypass capacitance, 4.7µF of output
capacitor is recommended. With a 1000pF bypass capaci-
tor or larger, a 6.8µF output capacitor is recommended.
The shaded region of Figure 3 defines the range over
which the LT1962 regulators are stable. The minimum ESR
needed is defined by the amount of bypass capacitance
used, while the maximum ESR is 3Ω.
Figure 3. Stability
OUTPUT CAPACITANCE (µF)
1
ESR (Ω)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
03
10
1962 F03
2 4 5 67 8 9
STABLE REGION
CBYP = 330pF
CBYP ≥ 1000pF
CBYP = 100pF
CBYP = 0
Figure 5. Ceramic Capacitor Temperature Characteristics
Figure 4. Ceramic Capacitor DC Bias Characteristics
Figure 6. Noise Resulting from Tapping on a Ceramic Capacitor
DC BIAS VOLTAGE (V)
CHANGE IN VALUE (%)
1962 F04
20
0
–20
–40
–60
–80
–100 04810
2 6 12 14
X5R
Y5V
16
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
TEMPERATURE (°C)
–50
40
20
0
–20
–40
–60
–80
–100 25 75
1962 F05
–25 0 50 100
125
Y5V
CHANGE IN VALUE (%)
X5R
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
100ms/DIV 1962 F06
VOUT
500µV/DIV
LT1962-5
COUT = 10µF
CBYP = 0.01µF
ILOAD = 100mA
LT1962 Series
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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.
The resulting voltages produced can cause appreciable
amounts of noise, especially when a ceramic capacitor is
used for noise bypassing. A ceramic capacitor produced
Figure 6’s trace in response to light tapping from a pencil.
Similar vibration induced behavior can masquerade as
increased output voltage noise.
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 Character-
istics section. Power dissipation will be equal to the sum
of the two components listed above.
The LT1962 series regulators have internal thermal
limiting designed to protect the device during overload
conditions. For continuous normal conditions, the maxi-
mum 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 ambi-
ent. Additional heat sources mounted nearby must also
be considered.
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 gener-
ated 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 1/16" FR-4 board with one ounce
copper.
Table 1. Measured Thermal Resistance
COPPER AREA
BOARD AREA
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)TOPSIDE* BACKSIDE
2500mm22500mm22500mm2110°C/W
1000mm22500mm22500mm2115°C/W
225mm22500mm22500mm2120°C/W
100mm22500mm22500mm2130°C/W
50mm22500mm22500mm2140°C/W
*Device is mounted on topside.
Calculating Junction Temperature
Example: Given an output voltage of 3.3V, an input volt-
age range of 4V to 6V, an output current range of 0mA
to 100mA 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) = 100mA
VIN(MAX) = 6V
IGND at (IOUT = 100mA, VIN = 6V) = 2mA
So,
P = 100mA(6V – 3.3V) + 2mA(6V) = 0.28W
The thermal resistance will be in the range of 110°C/W to
140°C/W depending on the copper area. So the junction
temperature rise above ambient will be approximately
equal to:
0.28W(125°C/W) = 35.3°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 + 35.3°C = 85.3°C
LT1962 Series
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applicaTions inForMaTion
divider is used to provide a regulated 1.5V output from the
1.22V reference when the output is forced to 20V. 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 13V difference between OUT and ADJ pin
divided by the 5mA maximum current into the ADJ pin
yields a minimum top resistor value of 2.6k.
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 7.
When the IN pin of the LT1962 is forced below the OUT
pin or the OUT pin is pulled above the IN pin, input cur-
rent will typically drop to less than 2µA. This can happen
if the input of the device 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.
Protection Features
The LT1962 regulators incorporate several protection
features which make them 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 devices are protected
against reverse input voltages, reverse output 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 opera-
tion, the junction temperature should not exceed 125°C.
The input of the device will withstand reverse voltages of
20V. Current flow into the device will be limited to less
than 1mA (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 output of the LT1962 can be pulled below ground
without damaging the device. If the input is left open cir-
cuit or grounded, the output can be pulled below ground
by 20V. For fixed voltage versions, the output will act like
a large resistor, typically 500k or higher, limiting current
flow to less than 40µA. For adjustable versions, the output
will act like an open circuit; no current will flow out of the
pin. If the input is powered by a voltage source, the output
will source the short-circuit current of the device and will
protect itself by thermal limiting. In this case, grounding
the SHDN pin will turn off the device and stop the output
from sourcing the short-circuit current.
The ADJ pin of the adjustable device 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.
In situations where the ADJ pin is connected to a resistor
divider that would pull the ADJ pin above its 7V clamp volt-
age if the output is pulled high, the ADJ pin input current
must be limited to less than 5mA. For example, a resistor
Figure 7. Reverse Output Current
OUTPUT VOLTAGE (V)
0 1
REVERSE OUTPUT CURRENT (µA)
30
40
50
60
70
80
90
100
8 97
1962 F07
20
10
02 3 46
5
10
LT1962
LT1962-5
TJ = 25°C
VIN = 0V
CURRENT FLOWS
INTO OUTPUT PIN
VOUT = VADJ (LT1962)
LT1962-1.5
LT1962-1.8
LT1962-2.5
LT1962-3
LT1962-3.3
LT1962 Series
16
1962fa1962fb
For more information www.linear.com/LT1962
package DescripTion
MS8 Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660 Rev G)
MSOP (MS8) 0213 REV G
0.53 ±0.152
(.021 ±.006)
SEATING
PLANE
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.18
(.007)
0.254
(.010)
1.10
(.043)
MAX
0.22 – 0.38
(.009 – .015)
TYP
0.1016 ±0.0508
(.004 ±.002)
0.86
(.034)
REF
0.65
(.0256)
BSC
0° – 6° TYP
DETAIL “A”
DETAIL “A”
GAUGE PLANE
1 2 34
4.90 ±0.152
(.193 ±.006)
8765
3.00 ±0.102
(.118 ±.004)
(NOTE 3)
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
0.52
(.0205)
REF
5.10
(.201)
MIN
3.20 – 3.45
(.126 – .136)
0.889 ±0.127
(.035 ±.005)
RECOMMENDED SOLDER PAD LAYOUT
0.42 ± 0.038
(.0165 ±.0015)
TYP
0.65
(.0256)
BSC
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660 Rev G)
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
LT1962 Series
17
1962fa1962fb
For more information www.linear.com/LT1962
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
revision hisTory
REV DATE DESCRIPTION PAGE NUMBER
B 5/15 Clarified the Order Information table.
Added I-grade option.
2
2, 4
(Revision history begins at Rev B)
LT1962 Series
18
1962fa1962fb
For more information www.linear.com/LT1962
LINEAR TECHNOLOGY CORPORATION 2000
LT 0515 REV B • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LT1962
relaTeD parTs
Typical applicaTion
Paralleling of Regulators for Higher Output CurrentAdjustable Current Source
C4
0.01µF
R1
0.1Ω
R2
0.1Ω
R5
10k
R4
2.2k
R7
1.21k
C2
10µF
1962 TA03
V
IN > 3.7V
3.3V
300mA
C5
0.01µF
8
1
3
2
4
C3
0.01µF
IN
SHDN
OUT
FB
BYP
GND
LT1962-3.3
IN
SHDN
OUT
BYP
ADJ
GND
LT1962
SHDN
+
C1
10µF
+
–
+
1/2 LT1490
R6
2k
R3
2.2k
IN
SHDN
OUT
VIN
>2.7V
FB
GND
LT1962-2.5
R7
100k
C1
10µF
*ADJUST R1 FOR 0mA TO 300mA
CONSTANT CURRENT
+
R6
2.2k
LT1004-1.2
C3
0.33µF
C2
1µF
1962 TA04
R5
0.1Ω
R4
2.2k
R3
2k
R2
40.2k
R1*
1k
–
+
LOAD
1/2 LT1490
PART NUMBER DESCRIPTION COMMENTS
LT1120 125mA Low Dropout Regulator with 20µA IQIncludes 2.5V Reference and Comparator
LT1121 150mA Micropower Low Dropout Regulator 30µA IQ, SOT-223 Package
LT1129 700mA Micropower Low Dropout Regulator 50µA Quiescent Current
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LT1521 300mA Low Dropout Micropower Regulator with Shutdown 15µA IQ, Reverse Battery Protection
LT1529 3A Low Dropout Regulator with 50µA IQ500mV Dropout Voltage
LTC
®
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LT1761 100mA, Low Noise, Low Dropout Micropower Regulator in SOT-23 20µA Quiescent Current, 20µVRMS Noise
LT1762 150mA, Low Noise, LDO Micropower Regulator 25µA Quiescent Current, 20µVRMS Noise
LT1763 500mA, Low Noise, LDO Micropower Regulator 30µA Quiescent Current, 20µVRMS Noise
LT1764 3A, Fast Transient Response Low Dropout Regulator 340mV Dropout Voltage, 40µVRMS Noise
LTC1772 Constant Frequency Current Mode Step-Down DC/DC Controller Up to 94% Efficiency, SOT-23 Package, 100% Duty Cycle
LT1963 1.5A, Fast Transient Response Low Dropout Regulator SO-8, SOT-223 Packages