Texas Instruments TLV431BCLPE3

Overview

TLV431BCLPE3 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 0.5% initial reference voltage tolerance at 25°C, 1.24 V nominal reference voltage, and operation down to 1.24 V cathode-anode voltage. It delivers 0.25 Ω typical dynamic impedance, 80 µA typical minimum cathode current, and supports output voltage adjustment from 1.24 V to 6 V using two external resistors - ideal for secondary-side regulation in isolated 3.3 V flyback SMPSs.

For engineers reviewing the TLV431BCLPE3 datasheet, TLV431BCLPE3 pinout, TLV431BCLPE3 application, or TLV431BCLPE3 equivalent, key selection considerations include its SC-70 (DCK) package footprint, thermal stability across –40°C to 125°C (Q-grade), ultra-low I_REF (0.1–0.5 µA), and compatibility with optocoupler-based feedback loops requiring sharp turn-on and stable Zener replacement behavior.

Technical Context

The TLV431BCLPE3 integrates an internal 1.24 V bandgap reference and high-gain NPN-based error amplifier driving a Darlington sink output stage. Its open-loop comparator mode enables precise voltage monitoring with integrated reference, while closed-loop configuration with resistive feedback realizes adjustable shunt regulation. The device operates without external compensation due to internal frequency compensation.

It functions as a 3-terminal programmable shunt regulator where the REF pin senses a fraction of cathode voltage via resistor divider, forcing cathode voltage to V_REF × (1 + R₁/R₂) + I_REF × R₁. Cathode current must exceed 55–100 µA depending on temperature grade to maintain regulation, and substrate connection (Pin 2 in DCK) must be tied to ANODE or left floating per TI specification.

Key Specifications

Pinout & Package

TLV431BCLPE3 uses the SC-70 (DCK) 6-pin package with 2.0 mm × 1.5 mm body size and 0.65 mm lead pitch. Pin 2 is substrate-connected and must be tied to ANODE or left unconnected; Pin 4 and Pin 5 are NC (no internal connection).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt regulator applications.

Compared with TLV431ACLPE3, TLV431BCLPE3 provides tighter reference accuracy for precision feedback loops; compared with TLVH431ILP, it offers superior board-area efficiency and lower quiescent current but sacrifices voltage headroom and current capability.

Availability

TLV431BCLPE3 is available at Aetrix Electronics and suitable for isolated SMPS regulation, voltage monitoring, Zener replacement, and comparator-based threshold detection requiring stable component supply and guaranteed long-term manufacturability.

Supply support for TLV431BCLPE3 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and power management ICs, with decades of leadership in precision reference and power control technologies.

The TLV431 family was designed specifically for low-voltage, high-accuracy shunt regulation in space-constrained and energy-efficient applications - targeting 3.3 V/5 V isolated power supplies, battery management, and industrial sensing interfaces.

FAQ

What is the reference voltage tolerance of TLV431BCLPE3 at 25°C?

The TLV431BCLPE3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a V_REF range of 1.234 V to 1.246 V under standard test conditions (V_KA = V_REF, I_K = 10 mA). This tight tolerance is specified for the 'B' grade variant and is confirmed in Section 5.7 of the TI SLVS139Z datasheet.

Which package does TLV431BCLPE3 use, and what are its dimensions?

TLV431BCLPE3 uses the SC-70 (DCK) package, measuring 2.0 mm × 1.5 mm with 0.65 mm lead pitch. This ultra-small outline is 40% smaller than SOT-23-3 and features six pins, including two NC terminals and a substrate-connected Pin 2 that must be tied to ANODE or left open per TI's pin function table.

Can TLV431BCLPE3 replace a standard Zener diode in a circuit?

Yes, TLV431BCLPE3 can directly replace low-voltage Zener diodes (e.g., 1N4728A) in applications requiring 1.24–6 V regulation. Its advantages include 0.5% initial accuracy, 0.25 Ω dynamic impedance, and sharp turn-on - delivering significantly better regulation stability and temperature performance than discrete Zeners.

What is the minimum cathode current required for TLV431BCLPE3 to regulate properly?

The TLV431BCLPE3 requires a minimum cathode current (I_K(min)) of 55 µA at 25°C and up to 100 µA over the full –40°C to 125°C temperature range to maintain regulation. This value is substantially lower than the 1 mA minimum for TL431, making TLV431BCLPE3 suitable for ultra-low-power designs.

How does TLV431BCLPE3 behave in open-loop comparator mode?

In open-loop comparator mode, TLV431BCLPE3 compares voltage at the REF pin to its internal 1.24 V reference. With sufficient cathode current (>100 µA), it delivers fast switching between ~1 V (low) and V_CC (high, open-collector), enabling precise voltage threshold detection without external reference components.