The LM431A/LM431B/LM431C are three-terminal output adjustable regulators with thermal stability over operating temperature range. The output voltage can be set any value between VREF (approximately 2.5 volts) and 36 volts with two external resistors. These devices have a typical dynamic output impedance of 0.2W. Active output circuit provides a sharp turn-on characteristic, making these devices excellent replacement for Zener Diodes in many applications. Product Highlights: Programmable output voltage to 36 volts Low dynamic output impedance 0.20 typical Sink current capability of 1.0 to 100mA Equivalent full-range temperature coefficient of 50ppm/C typical Temperature compensated for operation over full rated operating temperature range Low output noise voltage Fast turn-on response
The LM431 is a 3-terminal adjustable shunt regulator with guaranteed temperature stability over the entire temperature range of operation. It is now available in a chip sized package (4-Bump micro SMD) using National's micro SMD package technology. The output voltage may be set at any level greater than 2.5V (VREF) up to 36V merely by selecting two external resistors that act as a voltage divided network. Due to the sharp turn-on characteristics this device is an excellent replacement for many zener diode applications.