LT1963A Series
1.5A, Low Noise,
Fast Transient Response
LDO Regulators
FEATURES
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DESCRIPTION
The LT
®
1963A 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 regula-
tors. In addition to fast transient response, the LT1963A
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 LT1963A
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 LT1963A regula-
tors are available in 5-lead TO-220, DD, 3-lead SOT-223,
8-lead SO and 16-lead TSSOP packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 6118263, 6144250.
*See Applications Information Section.
Optimized for Fast Transient Response
Output Current: 1.5A
Dropout Voltage: 340mV
Low Noise: 40μV
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*
Stable with Ceramic Capacitors*
Reverse Battery Protection
No Reverse Current
Thermal Limiting
5-Lead TO-220, DD, 3-Lead SOT-223 and
8-Lead SO Packages
APPLICATIONS
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3.3V to 2.5V Logic Power Supplies
Post Regulator for Switching Supplies
TYPICAL APPLICATION
Dropout Voltage
3.3V to 2.5V Regulator
DROPOUT VOLTAGE (mV)
IN
10μF*
OUT
2.5V
1.5A
10μF*
400
350
+
V
IN
> 3V
+
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
1963A TA02
LT1963A-2.5
SHDN
SENSE
GND
1963A TA01
*TANTALUM,
CERAMIC OR
ALUMINUM ELECTROLYTIC
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LT1963A Series
ABSOLUTE MAXIMUM RATINGS
(Note 1)
IN Pin Voltage ........................................................ ± 20V
OUT Pin Voltage ......................................................±20V
Input to Output Differential Voltage (Note 2) ...........±20V
SENSE Pin Voltage ............................................... ± 20V
ADJ Pin Voltage ...................................................... ±7V
SHDN
Pin Voltage ................................................. ±20V
Output Short-Circuit Duration ........................ Indefinite
Operating Junction Temperature Range (Note 3)
LT1963AE...........................................– 40°C to 125°C
LT1963AI............................................– 40°C to 125°C
LT1963AMP .......................................– 55°C to 125°C
Storage Temperature Range...................– 65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
TOP VIEW
GND
NC
FRONT VIEW
5
4
TAB IS
GND
3
2
1
Q PACKAGE
5-LEAD PLASTIC DD
SENSE/ADJ*
OUT
GND
IN
SHDN
TAB IS
GND
FRONT VIEW
5
4
3
2
1
T PACKAGE
5-LEAD PLASTIC TO-220
SENSE/
ADJ*
OUT
GND
IN
SHDN
OUT
OUT
OUT
SENSE/ADJ*
GND
GND
1
2
3
4
5
6
7
8
17
16 GND
15 NC
14 IN
13 IN
12 IN
11 NC
10
SHDN
9
GND
*PIN 5 = SENSE FOR LT1963A-1.5/LT1963A-1.8/
LT1963A-2.5/LT1963A-3.3
= ADJ FOR LT1963A
T
JMAX
= 150°C,
θ
JA
= 30°C/ W
*PIN 5 = SENSE FOR LT1963A-1.5/LT1963A-1.8/
LT1963A-2.5/LT1963A-3.3
= ADJ FOR LT1963A
T
JMAX
= 150°C,
θ
JA
= 50°C/ W
FE PACKAGE
16-LEAD PLASTIC TSSOP
EXPOSED PAD (PIN 17) IS GND. MUST BE
SOLDERED TO THE PCB.
*PIN 6 = SENSE FOR LT1963A-1.5/LT1963A-1.8/
LT1963A-2.5/LT1963A-3.3
= ADJ FOR LT1963A
T
JMAX
= 150°C,
θ
JA
= 38°C/ W
FRONT VIEW
3
TAB IS
GND
2
1
OUT
GND
IN
OUT 1
SENSE/ADJ* 2
GND 3
NC 4
TOP VIEW
8
7
6
5
IN
GND
GND
SHDN
ST PACKAGE
3-LEAD PLASTIC SOT-223
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 50°C/ W
*PIN 2 = SENSE FOR LT1963A-1.5/LT1963A-1.8/
LT1963A-2.5/LT1963A-3.3
= ADJ FOR LT1963A
T
JMAX
= 150°C,
θ
JA
= 70°C/ W
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LT1963A Series
ELECTRICAL CHARACTERISTICS
PARAMETER
Minimum Input Voltage (Notes 4,12)
Regulated Output Voltage (Note 5)
CONDITIONS
I
LOAD
= 0.5A
I
LOAD
= 1.5A
LT1963A-1.5
LT1963A-1.8
LT1963A-2.5
LT1963A-3.3
ADJ Pin Voltage (Notes 4, 5)
Line Regulation
LT1963A
LT1963A-1.5
LT1963A-1.8
LT1963A-2.5
LT1963A-3.3
LT1963A (Note 4)
LT1963A-1.5
LT1963A-1.8
LT1963A-2.5
LT1963A-3.3
LT1963A (Note 4)
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
●
●
l
The
l
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
MIN
TYP
1.9
2.1
1.477
1.447
1.773
1.737
2.462
2.412
3.250
3.200
1.192
1.174
1.500
1.500
1.800
1.800
2.500
2.500
3.300
3.300
1.210
1.210
2.0
2.5
3.0
3.5
1.5
2
2
2.5
3
2
0.02
0.10
0.19
0.34
1.0
1.1
3.8
15
80
40
3
0.25
0.90
0.75
0.01
3
0.01
10
2
1
30
1
MAX
2.5
1.523
1.545
1.827
1.854
2.538
2.575
3.350
3.400
1.228
1.246
6
7
10
10
5
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
UNITS
V
V
V
V
V
V
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
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
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
ΔV
IN
= 2.21V to 20V, I
LOAD
= 1mA
ΔV
IN
= 2.3V to 20V, I
LOAD
= 1mA
ΔV
IN
= 3V to 20V, I
LOAD
= 1mA
ΔV
IN
= 3.8V to 20V, I
LOAD
= 1mA
ΔV
IN
= 2.21V to 20V, I
LOAD
= 1mA
V
IN
= 2.5V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 2.5V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 2.8V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 2.8V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 3.5V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 3.5V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 4.3V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 4.3V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 2.5V,
ΔI
LOAD
= 1mA to 1.5A
V
IN
= 2.5V,
ΔI
LOAD
= 1mA to 1.5A
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Load Regulation
Output Voltage Noise
ADJ Pin Bias Current
Shutdown Threshold
SHDN
Pin Current (Note 10)
Quiescent Current in Shutdown
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