AS2955/56/57
350mA Low Drop Out Voltage Regulator
with Shutdown
(PRELIMINARY INFORMATION)
FEATURES
•
Output Accuracy 5V, 3.3V@ 350mA Output
•
Very Low Quiescent Current
•
Low Dropout Voltage
•
Extremely Tight Load And Line Regulation
•
Very Low Temperature Coefficient
•
Current & Thermal Limiting
•
Error Flag Warns Of Output Dropout
•
Logic-Controlled Electronic Shutdown
•
Output Programmable From 1.24V to 29V
APPLICATIONS
•
Battery Powered Systems
•
Cordless Telephones
•
Radio Control Systems
•
Portable/Palm Top/Notebook Computers
•
Portable Consumer Equipment
•
Portable Instrumentation
•
Automotive Electronics
•
SMPS Post-Regulator
•
Voltage Reference
PRODUCT DESCRIPTION
The AS2955/56/57 is a low power voltage regulator. This device is an excellent choice for use in battery-powered applications such as
cordless telephones, radio control systems, and portable computers. The AS2955/56/57 features very low quiescent current (100µA
Typ.) and very low dropout voltage. This includes a tight initial tolerance of 1% max and 2% max., and very low output temperature
coefficient, making the AS2955/56/57 useful as a low-power voltage reference.
The error flag output feature is used as power-on reset for warning of a low output voltage, due to a falling voltage input of batteries.
Another feature is the logic-compatible shutdown input which enables the regulator to be switched on and off. The AS2955/56/57 is
offered in 3-pin and 5-pin TO-220 package compatible with other 5 volt and adjustable regulators, in 8-Pin Plastic Dip SO-8 (same pin
out as AS2951) and surface mount TO-263 packages.
The regulator output voltage (of the 8-pin package and 5-pin TO-220 & TO-263) may be pin-strapped for a 5V and 3.3V or
programmed from 1.24V to 29V with an external pair of resistors. Look for AS2951 for 150mA and AS2954 for 250mA applications.
ORDERING INFORMATION
TO-220
3 / 5- PIN
AS2955/56/57YU-X
TO-263
3 / 5-PIN
AS2955/56/57YT-X
PLASTIC
SOIC
8-PIN
AS2955YS-X
OPER.
TEMP.
RANGE
-40°C to +125°C
TO-263-3 Package
3 V
OUT
AS2955
2 GND
1 V
IN
Y= Output Tolerance(A = 1%; Blank for 2%)
X= Output Voltage(3.3V, 5.0V or Blank for Adj)
TO-220-5 Package
Front View
Consult factory for other fixed voltages.
TO-263-5 Package
8-Pin Surface Mount
AS2956/57
Five Lead Package Pin Functions:
AS2957
AS2956
1)
ERROR
2)
INPUT
3)
GND
1 2 3 4 5
4)
OUTPUT
5)
SHUTDOWN
ADJUST
SHUTDOWN
GND
INPUT
OUTPUT
AS2956/57
OUTPUT
SENSE
SHUTDOWN
GROUND
1
2
8
INPUT
FEEDBACK
5V/ 3.3V TAP
ERROR
TO-220-3 Package
3
V
OUT
GND
V
IN
ALPHA
7
5
AS2930
3
AS2955
6
4
AS2955
2
1
Top View
1 2 34 5
Top View
Front View
Top View
Rev. 10/6/00
SIPEX [ SIPEX CORPORATION ]
