General Description
The APL1431 is a 3-terminal adjustable voltage reference with specified thermal stability over applicable commercial temperature ranges. Output voltage may be set to any value between Vref (2.5 V) and 20 V with two external resistors (see Figure 2). When used with an photocoupler, the APL1431 is an ideal voltage reference in isolated feedback circuits for 2.5V to 12V switching-mode power supplies. This device has a typical output impedance of 0.1Ω. Active output circuitry provides a very sharp turn-on characteristic,making the APL1431 excellent replacements for zener diodes in many applications, including on-board regulation and adjustable power supplies.

Features
• Precise Reference Voltage to 2.500V
• Guaranteed 0.5% or 1% Reference Voltage Tolerance
• Sink Current Capability , 1mA to 100mA
• Quick Turn-on
• Adjustable Output Voltage , VO = VREF to 20V
• Low Operational Cathode Current , 250µA Typical
• 0.1Ω Typical Output Impedance
• SOT-23 , SOT-89 and TO-92 Packages

Applications
• Linear Regulators
• Adjustable Power Supply
• Switching Power Supply