LT1963 Series
1.5A, Low Noise,
Fast Transient Response
LDO Regulators
FEATURES
s
s
s
s
s
s
s
s
s
s
s
s
s
s
DESCRIPTIO
Optimized for Fast Transient Response
Output Current: 1.5A
Dropout Voltage: 340mV
Low Noise: 40
µ
V
RMS
(10Hz to 100kHz)
1mA Quiescent Current
No Protection Diodes Needed
Controlled Quiescent Current in Dropout
Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3.3V
Adjustable Output from 1.21V to 20V
< 1µA Quiescent Current in Shutdown
Stable with 10µF Output Capacitor
Reverse Battery Protection
No Reverse Current
Thermal Limiting
APPLICATIO S
s
s
3.3V to 2.5V Logic Power Supplies
Post Regulator for Switching Supplies
The LT
®
1963 series are low dropout regulators optimized
for fast transient response. The devices are capable of
supplying 1.5A of output current with a dropout voltage of
340mV. Operating quiescent current is 1mA, dropping to
< 1µA in shutdown. Quiescent current is well controlled; it
does not rise in dropout as it does with many other
regulators. In addition to fast transient response, the
LT1963 regulators have very low output noise which
makes them ideal for sensitive RF supply applications.
Output voltage range is from 1.21V to 20V. The LT1963
regulators are stable with output capacitors as low as
10µF. Internal protection circuitry includes reverse battery
protection, current limiting, thermal limiting and reverse
current protection. The devices are available in fixed
output voltages of 1.5V, 1.8V, 2.5V, 3.3V and as an
adjustable device with a 1.21V reference voltage. The
LT1963 regulators are available in 5-lead TO-220, DD,
3-lead SOT-223 and 8-lead SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
Dropout Voltage
400
3.3V to 2.5V Regulator
DROPOUT VOLTAGE (mV)
350
300
250
200
150
100
50
0
0
0.2
0.4 0.6 0.8 1.0 1.2
OUTPUT CURRENT (A)
1.4 1.6
1963 TA02
+
V
IN
> 3V
10µF
IN
OUT
LT1963-2.5
+
10µF
2.5V
1.5A
SHDN
SENSE
GND
1963 TA01
U
1963fa
U
U
1
LT1963 Series
ABSOLUTE
AXI U
RATI GS
(Note 1)
SHDN Pin Voltage .................................................
±20V
Output Short-Circuit Duration ......................... Indefinite
Operating Junction Temperature Range – 45°C to 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
IN Pin Voltage ........................................................
±20V
OUT Pin Voltage ....................................................
±20V
Input to Output Differential Voltage (Note 2) .........
±20V
SENSE Pin Voltage ...............................................
±20V
ADJ Pin Voltage ......................................................
±7V
PACKAGE/ORDER I FOR ATIO
FRONT VIEW
5
4
TAB IS
GND
3
2
1
Q PACKAGE
5-LEAD PLASTIC DD
SENSE/ADJ*
OUT
GND
IN
SHDN
ORDER PART
NUMBER
LT1963EQ
LT1963EQ-1.5
LT1963EQ-1.8
LT1963EQ-2.5
LT1963EQ-3.3
ORDER PART
NUMBER
*PIN 5 = SENSE FOR LT1963-1.8/LT1963-2.5/LT1963-3.3
= ADJ FOR LT1963
T
JMAX
= 150°C,
θ
JA
= 30°C/ W
FRONT VIEW
3
TAB IS
GND
2
1
OUT
GND
IN
LT1963EST-1.5
LT1963EST-1.8
LT1963EST-2.5
LT1963EST-3.3
ST PART
MARKING
196315
196318
196325
196333
ST PACKAGE
3-LEAD PLASTIC SOT-223
T
JMAX
= 150°C,
θ
JA
= 50°C/ W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C. (Note 3)
PARAMETER
CONDITIONS
q
Minimum Input Voltage (Notes 4,12) I
LOAD
= 0.5A
I
LOAD
= 1.5A
Regulated Output Voltage (Note 5)
LT1963-1.5
LT1963-1.8
V
IN
= 2.21V, I
LOAD
= 1mA
2.5V < V
IN
< 20V, 1mA < I
LOAD
< 1.5A
V
IN
= 2.3V, I
LOAD
= 1mA
2.8V < V
IN
< 20V, 1mA < I
LOAD
< 1.5A
2
U
U
W
W W
U
W
FRONT VIEW
5
4
3
2
1
TAB IS
GND
T PACKAGE
5-LEAD PLASTIC TO-220
SENSE/ADJ*
OUT
GND
IN
SHDN
ORDER PART
NUMBER
LT1963ET
LT1963ET-1.5
LT1963ET-1.8
LT1963ET-2.5
LT1963ET-3.3
ORDER PART
NUMBER
*PIN 5 = SENSE FOR LT1963-1.8/LT1963-2.5/LT1963-3.3
= ADJ FOR LT1963
T
JMAX
= 150°C,
θ
JA
= 50°C/ W
TOP VIEW
OUT 1
SENSE/ADJ* 2
GND 3
NC 4
8
7
6
5
IN
GND
GND
SHDN
LT1963ES8
LT1963ES8-1.5
LT1963ES8-1.8
LT1963ES8-2.5
LT1963ES8-3.3
S8 PART
MARKING
1963
196315
196318
196325
196333
S8 PACKAGE
8-LEAD PLASTIC SO
*PIN 2 = SENSE FOR LT1963-1.8/LT1963-2.5/LT1963-3.3
= ADJ FOR LT1963
T
JMAX
= 150°C,
θ
JA
= 70°C/ W
MIN
TYP
1.9
2.1
MAX
2.5
1.523
1.545
1.827
1.854
UNITS
V
V
V
V
V
V
1963fa
q
q
1.477
1.447
1.773
1.737
1.500
1.500
1.800
1.800
LT1963 Series
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C. (Note 2)
PARAMETER
CONDITIONS
LT1963-2.5
LT1963-3.3
ADJ Pin Voltage
(Notes 4, 5)
Line Regulation
LT1963
LT1963-1.5
LT1963-1.8
LT1963-2.5
LT1963-3.3
LT1963 (Note 4)
LT1963-1.5
LT1963-1.8
LT1963-2.5
LT1963-3.3
V
IN
= 3V, I
LOAD
= 1mA
3.5V < V
IN
< 20V, 1mA < I
LOAD
< 1.5A
V
IN
= 3.8V, I
LOAD
= 1mA
4.3V < V
IN
< 20V, 1mA < I
LOAD
< 1.5A
V
IN
= 2.21V, I
LOAD
= 1mA
2.5V < V
IN
< 20V, 1mA < I
LOAD
< 1.5A
∆V
IN
= 2.21V to 20V, I
LOAD
= 1mA
∆V
IN
= 2.3V to 20V, I
LOAD
= 1mA
∆V
IN
= 3V to 20V, I
LOAD
= 1mA
∆V
IN
= 3.8V to 20V, I
LOAD
= 1mA
∆V
IN
= 2.21V to 20V, I
LOAD
= 1mA
V
IN
= 2.5V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 2.5V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 2.8V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 2.8V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 3.5V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 3.5V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 4.3V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 4.3V,
∆I
LOAD
= 1mA to 1.5A
q
q
q
q
q
q
q
q
q
MIN
2.462
2.412
3.250
3.200
1.192
1.174
TYP
2.500
2.500
3.300
3.300
1.210
1.210
2.0
2.5
3.0
3.5
1.5
2
2
MAX
2.538
2.575
3.350
3.400
1.228
1.246
10
10
10
10
10
9
18
10
20
15
30
20
35
8
15
0.06
0.10
0.17
0.22
0.27
0.35
0.45
0.55
1.5
1.6
5.5
25
120
10
2
1
30
1
UNITS
V
V
V
V
V
V
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
V
V
V
V
V
V
V
V
mA
mA
mA
mA
mA
µV
RMS
µA
V
V
µA
µA
µA
dB
A
A
Load Regulation
q
2.5
q
3
q
LT1963 (Note 4) V
IN
= 2.5V,
∆I
LOAD
= 1mA to 1.5A
V
IN
= 2.5V,
∆I
LOAD
= 1mA to 1.5A
Dropout Voltage
V
IN
= V
OUT(NOMINAL)
(Notes 6, 7, 12)
I
LOAD
= 1mA
I
LOAD
= 1mA
I
LOAD
= 100mA
I
LOAD
= 100mA
I
LOAD
= 500mA
I
LOAD
= 500mA
I
LOAD
= 1.5A
I
LOAD
= 1.5A
GND Pin Current
V
IN
= V
OUT(NOMINAL)
+ 1V
(Notes 6, 8)
I
LOAD
= 0mA
I
LOAD
= 1mA
I
LOAD
= 100mA
I
LOAD
= 500mA
I
LOAD
= 1.5A
C
OUT
= 10µF, I
LOAD
= 1.5A, BW = 10Hz to 100kHz
(Notes 4, 9)
V
OUT
= Off to On
V
OUT
= On to Off
V
SHDN
= 0V
V
SHDN
= 20V
V
IN
= 6V, V
SHDN
= 0V
V
IN
– V
OUT
= 1.5V (Avg), V
RIPPLE
= 0.5V
P-P
,
f
RIPPLE
= 120Hz, I
LOAD
= 0.75A
V
IN
= 7V, V
OUT
= 0V
V
IN
= V
OUT(NOMINAL)
+ 1V,
∆V
OUT
= – 0.1V
Q, T, S8 Packages V
IN
= – 20V, V
OUT
= 0V
ST Package
V
IN
= – 20V, V
OUT
= 0V
LT1963-1.5
LT1963-1.8
LT1963-2.5
LT1963-3.3
LT1963 (Note 4)
V
OUT
= 1.5V, V
IN
< 1.5V
V
OUT
= 1.8V, V
IN
< 1.8V
V
OUT
= 2.5V, V
IN
< 2.5V
V
OUT
= 3.3V, V
IN
< 3.3V
V
OUT
= 1.21V, V
IN
< 1.21V
2
q
0.02
q
0.10
q
0.19
q
0.34
q
q
q
q
q
q
1.0
1.1
3.8
15
80
40
3
Output Voltage Noise
ADJ Pin Bias Current
Shutdown Threshold
SHDN Pin Current
(Note 10)
Quiescent Current in Shutdown
Ripple Rejection
Current Limit
Input Reverse Leakage Current (Note 13)
Reverse Output Current (Note 11)
q
q
0.25
0.90
0.75
0.01
3
0.01
55
63
2
q
q
q
1.6
1
2
600
600
600
600
300
1200
1200
1200
1200
600
mA
mA
µA
µA
µA
µA
µA
1963fa
3
LT1963 Series
ELECTRICAL CHARACTERISTICS
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
Absolute maximum input to output differential voltage can not 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 LT1963 regulators are tested and specified under pulse load
conditions such that T
J
≈
T
A
. The LT1963 is 100% tested at
T
A
= 25°C. Performance at – 40°C and 125°C is assured by design,
characterization and correlation with statistical process controls.
Note 4:
The LT1963 (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 LT1963
(adjustable version) is tested and specified for these conditions with an
external resistor divider (two 4.12k resistors) for an output voltage of
2.4V. The external resistor divider will add a 300µA 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: V
IN
– V
DROPOUT
.
Note 8:
GND pin current is tested with V
IN
= V
OUT(NOMINAL)
+ 1V and a
current source load. The GND pin current will decrease 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.
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 LT1963, LT1963-1.5 and LT1963-1.8 dropout voltage will
be limited by the minimum input voltage specification under some output
voltage/load conditions.
Note 13.
For the ST package, the input reverse leakage current increases
due to the additional reverse leakage current for the SHDN pin, which is
tied internally to the IN pin.
TYPICAL PERFOR A CE CHARACTERISTICS
Typical Dropout Voltage
500
450
400
DROPOUT VOLTAGE (mV)
600
GUARANTEED DROPOUT VOLTAGE (mV)
350
300
250
200
150
100
50
0
0
0.2
DROPOUT VOLTAGE (mV)
T
J
= 125°C
T
J
= 25°C
0.4 0.6 0.8 1.0 1.2
OUTPUT CURRENT (A)
Quiescent Current
1.4
1.2
QUIESCENT CURRENT (mA)
LT1963-1.8/-2.5/-3.3
OUTPUT VOLTAGE (V)
1.0
0.8
0.6
0.4
0.2
V
IN
= 6V
R
L
=
∞,
I
L
= 0
V
SHDN
= V
IN
50
25
75
0
TEMPERATURE (°C)
100
125
LT1963
1.81
1.80
1.79
1.78
1.77
1.76
–50 –25
0
25
50
75
100
125
OUTPUT VOLTAGE (V)
0
– 50 – 25
4
U W
1.4
1963 • G01
1963
G04
Guaranteed Dropout Voltage
TEST POINTS
Dropout Voltage
500
450
500
T
J
≤
125°C
400
T
J
≤
25°C
300
200
100
0
400
350
300
250
200
150
100
50
I
L
= 100mA
I
L
= 1mA
–25
50
0
75
25
TEMPERATURE (°C)
100
125
I
L
= 0.5A
I
L
= 1.5A
1.6
0
0.2
0.4 0.6 0.8 1.0 1.2
OUTPUT CURRENT (A)
1.4
1.6
0
–50
1963 • G02
1963 G03
LT1963-1.8 Output Voltage
1.84
I
L
= 1mA
1.83
1.82
2.56
2.54
2.52
2.50
2.48
2.46
2.44
2.58
LT1963-2.5 Output Voltage
I
L
= 1mA
2.42
–50 –25
0
25
50
75
100
125
TEMPERATURE (°C)
1963 G05
TEMPERATURE (°C)
1963 G06
1963fa
LT1963 Series
TYPICAL PERFOR A CE CHARACTERISTICS
LT1963-3.3 Output Voltage
3.38
I
L
= 1mA
3.36
1.230
I
L
= 1mA
1.225
ADJ PIN VOLTAGE (V)
OUTPUT VOLTAGE (V)
3.34
3.32
3.30
3.28
3.26
3.24
3.22
–50 –25
0
25
50
75
100
125
1.220
1.215
1.210
1.205
1.200
1.195
1.190
–50 –25
0
25
50
75
100
125
QUIESCENT CURRENT (mA)
TEMPERATURE (°C)
1963 G07
LT1963-2.5 Quiescent Current
14
12
QUIESCENT CURRENT (mA)
10
8
6
4
2
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
14
T
J
= 25°C
R
L
=
∞
V
SHDN
= V
IN
12
QUIESCENT CURRENT (mA)
10
8
6
4
2
0
QUIESCENT CURRENT (mA)
LT1963-1.8 GND Pin Current
25
25
GND PIN CURRENT (mA)
GND PIN CURRENT (mA)
15
15
GND PIN CURRENT (mA)
T
J
= 25°C
V
SHDN
= V
IN
20 *FOR V
OUT
= 1.18V
10
R
L
= 6, I
L
= 300mA*
R
L
= 18, I
L
= 100mA*
R
L
= 180, I
L
= 10mA*
5
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
U W
1963 G10
1963 G13
LT1963 ADJ Pin Voltage
14
12
10
8
6
4
2
0
LT1963-1.8 Quiescent Current
T
J
= 25°C
R
L
=
∞
V
SHDN
= V
IN
0
1
2
TEMPERATURE (°C)
1963 G08
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1963 G09
LT1963-3.3 Quiescent Current
T
J
= 25°C
R
L
=
∞
V
SHDN
= V
IN
LT1963 Quiescent Current
14
12
10
8
6
4
2
T
J
= 25°C
R
L
= 4.3k
V
SHDN
= V
IN
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
0
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
1963 G12
1963 G11
LT1963-2.5 GND Pin Current
T
J
= 25°C
V
SHDN
= V
IN
*FOR V
OUT
= 2.5V
25
LT1963-3.3 GND Pin Current
T
J
= 25°C
V
SHDN
= V
IN
*FOR V
OUT
= 3.3V
20
20
R
L
= 8.33, I
L
= 300mA*
15
R
L
= 11, I
L
= 300mA*
10
R
L
= 25, I
L
= 100mA*
10
5
5
R
L
= 33, I
L
= 100mA*
R
L
= 330, I
L
= 100mA*
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
0
0
1
2
R
L
= 250, I
L
= 10mA*
3 4 5 6 7
INPUT VOLTAGE (V)
8
9 10
1963 G14
0
1963 G15
1963fa
5
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