Texas Instruments TLV431BQDBZRG4

Overview

TLV431BQDBZRG4 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, 80 µA typical minimum cathode current, and operation up to 6 V cathode-anode voltage - used for secondary-side regulation in isolated flyback SMPSs and as a Zener diode replacement in space-constrained 3.3 V systems.

For engineers reviewing the TLV431BQDBZRG4 datasheet, TLV431BQDBZRG4 pinout, TLV431BQDBZRG4 application, or TLV431BQDBZRG4 equivalent, key selection criteria include reference accuracy over temperature (±11 mV from –40°C to 125°C), ultra-small SC-70 package footprint (2.0 mm × 1.5 mm), cathode current capability (100 µA min), dynamic impedance stability, and compatibility with optocoupler-based feedback loops.

Technical Context

The TLV431BQDBZRG4 implements a bandgap-referenced error amplifier driving a Darlington sink output stage, enabling precise shunt regulation without external compensation. Its internal reference is trimmed to 1.24 V with 0.5% initial accuracy and exhibits 11 mV total deviation across –40°C to 125°C.

It operates in two functional modes: open-loop comparator mode (with integrated 1.24 V threshold) and closed-loop shunt regulator mode (using external resistive feedback between cathode and reference pins). The device requires ≥100 µA cathode current to maintain linear regulation and stable gain across its full operating range.

Key Specifications

Pinout & Package

TLV431BQDBZRG4 uses the DCK (SC-70) 6-pin package (2.0 mm × 1.5 mm), offering 40% smaller footprint than SOT-23-3. 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 TLV431BQDBZRG4, TLV431BIDBZR offers identical regulation performance in a larger, more thermally robust package, while TLVH431ILP extends voltage and current capability at the cost of reduced accuracy and larger form factor - neither is pin-compatible, but both serve adjacent design needs.

Availability

TLV431BQDBZRG4 is available at Aetrix Electronics and suitable for isolated flyback SMPSs, precision voltage monitoring circuits, and low-voltage Zener replacement applications requiring stable component supply and automotive-grade temperature support (–40°C to 125°C).

Supply support for TLV431BQDBZRG4 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 delivering analog and embedded processing solutions, with leadership in precision analog, power management, and signal chain technologies.

The TLV431 family was designed specifically for low-voltage, high-accuracy shunt regulation in space-constrained and thermally demanding applications - targeting isolated power supplies, voltage supervision, and compact current-sink circuits.

FAQ

What is the reference voltage tolerance of TLV431BQDBZRG4 at 25°C?

The TLV431BQDBZRG4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal value with a range of 1.234 V to 1.246 V. This tight tolerance is specified in Section 5.7 of the TI datasheet and applies exclusively to the TLV431B grade - the 'B' suffix denotes this 0.5% initial accuracy. TLV431BQDBZRG4 maintains this specification across its qualified temperature range.

Does TLV431BQDBZRG4 require an output capacitor for stability?

No, TLV431BQDBZRG4 is internally compensated and remains stable without an output capacitor between cathode and anode. This is confirmed in Section 7.3 of the datasheet, which states it is "stable without an output capacitor." However, if a capacitor is added for noise filtering, Figure 5-19 provides phase-margin guidance to avoid instability - capacitance values above ~1 nF may degrade stability depending on load conditions.

What is the maximum cathode-anode voltage rating for TLV431BQDBZRG4?

The absolute maximum cathode-anode voltage (V_KA) for TLV431BQDBZRG4 is 7 V, as stated in Section 5.1 Absolute Maximum Ratings. Its recommended operating range is 1.24 V to 6 V, meaning the device functions reliably as a shunt regulator up to 6 V. Exceeding 7 V risks permanent damage, and operation above 6 V is outside guaranteed specifications.

How does TLV431BQDBZRG4 differ from TL431 in low-voltage applications?

TLV431BQDBZRG4 differs from TL431 by supporting operation down to 1.24 V reference voltage (vs. TL431's 2.5 V), requiring only 100 µA minimum cathode current (vs. TL431's 1 mA), and enabling regulation in 1.8 V–3.3 V systems where TL431 cannot function. These differences are explicitly documented in Section 7.1 Overview and make TLV431BQDBZRG4 the preferred choice for modern low-voltage isolated power supplies.

What package type is used by TLV431BQDBZRG4, and what are its dimensions?

TLV431BQDBZRG4 uses the DCK (SC-70) package - a 6-pin surface-mount outline measuring 2.0 mm × 1.5 mm (nominal length × width), as specified in the Package Information table and Section 11 Mechanical, Packaging, and Orderable Information. This package is 40% smaller than SOT-23-3 and features pins 1 (CATHODE), 3 (REFERENCE), and 6 (ANODE) as active terminals, with pins 2, 4, and 5 designated NC.