Texas Instruments TLV431BCDBZRG4

Overview

TLV431BCDBZRG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±0.5% initial tolerance at 25°C, 0.25 Ω typical dynamic impedance, and operation down to 1.24 V cathode-anode voltage. It serves as a Zener diode replacement or error amplifier in isolated flyback SMPS feedback loops requiring tight regulation below 3.3 V.

For engineers reviewing the TLV431BCDBZRG4 datasheet, TLV431BCDBZRG4 pinout, TLV431BCDBZRG4 application, or TLV431BCDBZRG4 equivalent, key selection factors include its SC-70 (DCK) package footprint, 80 µA typical minimum cathode current, 4 mV max VREF drift over 0°C to 70°C, and compatibility with optocoupler-based secondary-side regulation in compact power supplies.

Technical Context

The TLV431BCDBZRG4 implements a bandgap-referenced error amplifier with Darlington output stage, enabling precise shunt regulation via external resistor divider between cathode and reference pins. Its internal architecture supports both open-loop comparator mode (with integrated 1.24 V reference) and closed-loop shunt regulation mode without external compensation.

It operates across 0°C to 70°C (C-grade), delivers stable regulation with cathode currents from 55 µA to 15 mA, and maintains <0.4 Ω dynamic impedance up to 1 kHz - critical for transient response in feedback control loops of DC/DC converters and voltage monitors.

Key Specifications

Pinout & Package

TLV431BCDBZRG4 uses the SC-70 (DCK) 6-pin package with 2.0 mm × 1.5 mm footprint. Pin 1 is Cathode, Pin 3 is Reference, Pin 6 is Anode; Pins 2, 4, and 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 TLV431BCDBZRG4, TLV431ACDBZRG4 trades 0.5% accuracy for lower cost while retaining identical form factor and thermal performance; TLVH431IDBVR extends voltage range but sacrifices package compatibility and increases minimum cathode current requirement.

Availability

TLV431BCDBZRG4 is available at Aetrix Electronics and suitable for isolated flyback SMPS regulation, precision voltage monitoring, Zener diode replacement, and comparator-based threshold detection requiring stable component supply and long-term manufacturability.

Supply support for TLV431BCDBZRG4 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 designing analog ICs, embedded processors, and digital signal solutions for industrial, automotive, and communications markets.

The TLV431 family was developed specifically for low-voltage precision shunt regulation in space-constrained power management systems, targeting replacement of Zener diodes and legacy TL431-based designs in sub-3.3 V applications.

FAQ

What is the reference voltage accuracy of TLV431BCDBZRG4 over temperature?

The TLV431BCDBZRG4 has ±0.5% reference voltage tolerance at 25°C and exhibits ≤4 mV total deviation over the 0°C to 70°C operating range. This corresponds to ≤0.32% full-scale variation, verified per TI's SLVS139Z datasheet Section 5.7 and Figure 5-1. The device achieves this stability through bandgap reference design and on-die trimming.

Can TLV431BCDBZRG4 replace a standard Zener diode in a 2.5 V regulation circuit?

Yes, TLV431BCDBZRG4 can directly replace a Zener diode in 2.5 V regulation circuits. With its 1.24 V reference and external resistor divider, it sets V_OUT = 1.24 V × (1 + R1/R2). Its 0.25 Ω dynamic impedance and ±0.5% tolerance provide significantly better regulation accuracy and load transient response than typical 5% tolerance Zeners.

What is the minimum cathode current required for regulation in TLV431BCDBZRG4?

The TLV431BCDBZRG4 requires a minimum cathode current of 55 µA to enter regulation, with 80 µA typical at 25°C (per Section 5.7 of SLVS139Z). Below this threshold, the device may not maintain accurate reference voltage; design must ensure continuous IK ≥ 55 µA across all operating conditions including light-load and cold-temperature extremes.

Which package does TLV431BCDBZRG4 use, and how does it compare to SOT-23-3?

TLV431BCDBZRG4 uses the SC-70 (DCK) package, measuring 2.0 mm × 1.5 mm. This is 40% smaller than the SOT-23-3 footprint (2.92 mm × 2.37 mm) as stated in TI's Package Information table. The SC-70 offers identical 3-terminal functionality in a reduced area, ideal for high-density power modules and portable electronics.

How does TLV431BCDBZRG4 behave in open-loop comparator mode?

In open-loop comparator mode, TLV431BCDBZRG4 compares voltage at the Reference pin to its internal 1.24 V bandgap reference. When V_REF exceeds 1.24 V, the Cathode pulls low (~1 V); when below, Cathode floats near V_KA. It requires ≥55 µA cathode current for reliable switching and ≥10% overdrive for fast response, as detailed in Section 7.4.1 and Figure 8-3 of SLVS139Z.