DESCRIPTION The LX6431 series of precision adjustable three-terminal shunt voltage regulators are pin-to-pin compatible with the industry TL431 standard, but with significant improvements. The LX6431 is designed to eliminate unstable regions common to older generation shunt regulator products such as the TL431. The simpler task of designing is to eliminate insured capacitive loads, where the output voltage and cathode current do not combine and operate erratically. This capacitor value is chosen only for the best load transient response without the possibility of instability. The lower reference input current allows the use of higher value reference divider resistors, reducing battery current draw in portable devices, as well as reducing voltage due to programming errors in this divider network impedance (see highlighted product diagram below). In addition, the improved LX6431B has an initial accuracy of 0.4%, while the output voltage is programmable from 2.5V to 36V through two external resistors. These devices provide low output impedance for improved load regulation. Typical output impedance for these devices is 100mΩ. Reduced reference input bias current and minimum operating current make these devices suitable for portable and micro applications.

Key Features Unconditional stability of all cathode to anode capacitance values Reduced input current allows use of higher reference value divider resistors (0.5µA max.)
Preliminary reference voltage accuracy is 0.4% (LX6431B)
Sink current capability 0.6mA to 100mA
Typical output dynamic impedance minus greater than 100MΩ
Adjustable output voltage from 2.5V to 36V