ADJUSTABLE PRECISION SHUNT REGULATORS AS431
Data Sheet
1
Nov. 2005 Rev. 1. 1 BCD Semiconductor Manufacturing Limited
General Description
The AS431 series ICs are three-terminal adjustable
shunt regulators with guaranteed thermal stability over
a full operation range. These ICs feature sharp turn-on
characteristics, low temperature coefficient and low
output impedance, which make them ideal substitutes
for Zener diodes in applications such as switching
power supply, charger and other adjustable regulators.

The output voltage of these ICs can be set to any value
between V
REF
(2.5V) and the maximum cathode volt-
age (36V).
The AS431 precision reference is offered in two band-
gap tolerance: 0.4% and 0.8%.
These ICs are available in 4 Packages: TO-92, SOT-23-
3, SOT-23-5 and SOT-89 .
Features
·Programmable Precise Output Voltage from 2.5V
to 36V
·Very Accurate Reference Voltage: 0.15% Typical
·High Stability under Capacitive Load
·Low Temperature Deviation: 4.5mV Typical
·Low Equivalent Full-range Temperature Coeffi-
cient with 20PPM/
o
C Typical
·Low Dynamic Output Resistance: 0.15Ω Typical
·Sink Current Capacity from 1mA to 100 mA
·Low Output Noise
·Wide Operating Range of -40 to 125
o
C
Applications
·Charger
·Voltage Adapter
·Switching Power Supply
·Graphic Card
·Precision Voltage Reference
SOT-23-3
TO-92
SOT-89
Figure 1. Package Types of AS431
SOT-23-5