LMV431A

LMV431/LMV431A/LMV431B Low-Voltage (1.24V) Adjustable Precision Shunt Regulators August 2003 LMV431/LMV431A/LMV431B Low-Voltage (1.24V) Adjustable Precision Shunt Regulators General Description The LMV431, LMV431A and LMV431B are precision 1.24V shunt regulators capable of adjustment to 30V. Negative feedback from the cathode to the adjust pin controls the cathode voltage, much like a non-inverting op amp configuration (Refer to Symbol and Functional diagrams). A two resistor voltage divider terminated at the adjust pin controls the gain of a 1.24V band-gap reference. Shorting the cathode to the adjust pin (voltage follower) provides a cathode voltage of a 1.24V. The LMV431, LMV431A and LMV431B have respective initial tolerances of 1.5%, 1% and 0.5%, and functionally lends themselves to several applications that require zener diode type performance at low voltages. Applications include a 3V to 2.7V low drop-out regulator, an error amplifier in a 3V off-line switching regulator and even as a voltage detector. These parts are typically stable with capacitive loads greater than 10nF and less than 50pF. The LMV431, LMV431A and LMV431B provide performance at a competitive price. Features n Low Voltage Operation/Wide Adjust Range (1.24V/30V) n 0.5% Initial Tolerance (LMV431B) n Temperature Compensated for Industrial Temperature Range (39 PPM/˚C for the LMV431AI) n Low Operation Current (55µA) n Low Output Impedance (0.25Ω) n Fast Turn-On Response n Low Cost Applications n n n n...