CATHODE

REF

ANODE

CATHODE

REF

ANODE

+

_

Vref

11

TL431LI

TL432LI

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SLVSDQ6A – JULY 2018 – REVISED NOVEMBER 2018

Product Folder Links: TL431LI TL432LI

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Copyright © 2018, Texas Instruments Incorporated

9 Detailed Description

9.1 Overview

This standard device has proven ubiquity and versatility across a wide range of applications, ranging from power

to signal path. This is due to its key components containing an accurate voltage reference and op amp, which

are very fundamental analog building blocks. TL43xLI is used in conjunction with it's key components to behave

as a single voltage reference, error amplifier, voltage clamp or comparator with integrated reference.

TL43xLI can be operated and adjusted to cathode voltages from 2.495V to 36V, making this part optimum for a

wide range of end equipments in industrial, auto, telecom and computing. In order for this device to behave as a

shunt regulator or error amplifier, >1mA (Imin(max)) must be supplied in to the cathode pin. Under this condition,

feedback can be applied from the Cathode and Ref pins to create a replica of the internal reference voltage.

Various reference voltage options can be purchased with initial tolerances (at 25°C) of 0.5%, and 1%. These

reference options are denoted by B (0.5%) and A (1.0%) after the TL431LI or TL432LI. TL431LI and TL432LI are

both functionally the same, but have separate pinout options.

The TL43xLIxC devices are characterized for operation from 0°C to 70°C, the TL43xLIxI devices are

characterized for operation from –40°C to 85°C, and the TL43xLIxQ devices are characterized for operation from

–40°C to 125°C.

9.2 Functional Block Diagram

Figure 18. Equivalent Schematic

Figure 19. Detailed Schematic