Copyright  ANPEC Electronics Corp.
Rev. B.8 - Mar., 2005
APL431L
www.anpec.com.tw1
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise
customers to obtain the latest version of relevant information to verify before placing orders.
Low Voltage Adjustable Precision Shunt Regulator
Features General Description
Applications
The APL431L is a 3-terminal low voltage adjustable
precision reference with specified thermal stability
over applicable commercial temperature ranges. Out-
put voltage may be set to any value between V
ref
(1.
24 V) and 20 V with two external resistors (see Fig-
ure 2). When used with an photocoupler, the
APL431L is an ideal voltage reference in isolated feed-
back circuits for 3V to 12V switching-mode power
supplies. This device has a typical output imped-
ance of 0.1Ω. Active output circuitry provides a very
sharp turn-on characteristic,

making the APL431L ex-
cellent replacements for zener diodes in many
applications, including on-board regulation and ad-
justable power supplies.
• Precise Reference Voltage to 1.24V
• Guaranteed 0.5% or 1% Reference Voltage
Tolerance
• Sink Current Capability, 80uA to 100mA
• Quick Turn-on
• Adjustable Output Voltage, V
O
= V
REF
to 20V
• Low Operational Cathode Current, 80µA
Typical
• 0.1Ω Typical Output Impedance
• SOT-23-3, SOT-23-5, TO-92 and SOT-89
Packages
• Lead Free Available (RoHS Compliant)
• Linear Regulators
• Adjustable Power Supply
• Switching Power Supply
Symbol
Functional Diagram
Vref
+
_
Cathode
REF
Anode
SOT-23-3 (Top View)
REF
ANODE
CATHODE
12
3
SOT-89 (Top View)
REF ANODE CATHODE
123
REF
ANODE
CATHODE3
2
1
TO-92 (Top View)
CathodeAnode
REF
REF
NC
CATHODE
NC
ANODE
123
45
SOT-23-5 (Top View)