The TL431 is a three-terminal adjustable shunt regulator. The output voltage can be set to any value between Vref (approximately 2.5 V) and 36 V, with two external resistors.
TL431 has a typical output impedance of 0.2 Ω. Active output circuitry provides a very sharp turn-on characteristic, making these devices excellent replacements for Zener diodes in many applications, such as onboard regulation, adjustable power supplies, and switching power supplies.
Product feature:
• Reference voltage tolerance at 25°C
– 0.5% (B grade)
– 1% (A grade)
– 2% (Standard grade)
• Adjustable output voltage: Vref to 36 V
• Operation from −40°C to 125°C
• Low output noise
• 0.2-Ω Typical output impedance
• Sink-current capability: 1 mA to 100 mA
Applications:
• Adjustable voltage and current referencing
• Secondary side regulation in flyback SMPSs
• Zener replacement
• Voltage monitoring
• Comparator with integrated reference
• Hash board maintenance