LT1764 Series
3A, Fast Transient
Response, Low Noise,
LDO Regulators
FEATURES
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
DESCRIPTIO
Optimized for Fast Transient Response
Output Current: 3A
Dropout Voltage: 340mV at 3A
Low Noise: 40
µ
V
RMS
(10Hz to 100kHz)
1mA Quiescent Current
Wide Input Voltage Range: 2.7V to 20V
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
The LT
®
1764 is a low dropout regulator optimized for fast
transient response. The device is capable of supplying 3A
of output current with a dropout voltage of 340mV. Oper-
ating 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 LT1764 has very
low output voltage noise which makes the device ideal for
sensitive RF supply applications.
Output voltage range is from 1.21V to 20V. The LT1764
regulators are stable with output capacitors as low as 10µF.
Internal protection circuitry includes reverse battery pro-
tection, current limiting, thermal limiting and reverse cur-
rent protection. The device is 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 LT1764 regu-
lators are available in 5-lead TO-220 and DD packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
3.3V to 2.5V Logic Power Supply
Post Regulator for Switching Supplies
TYPICAL APPLICATIO
400
3.3V
IN
to 2.5V
OUT
Regulator
DROPOUT VOLTAGE (mV)
350
300
250
200
150
100
50
0
0
0.5
1.0
1.5
2.0
LOAD CURRENT (A)
2.5
3.0
1764 TA02
+
V
IN
> 3V
10µF
IN
OUT
LT1764-2.5
+
10µF
2.5V
3A
SHDN SENSE
GND
1764 TA01
U
Dropout Voltage
1764fa
U
U
1
LINER [ LINEAR TECHNOLOGY ]
