Texas Instruments TLV431BIDBZRG4

Overview

TLV431BIDBZRG4 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 - used for secondary-side regulation in isolated 3.3 V flyback SMPSs and as a Zener diode replacement in compact power rails.

For engineers reviewing the TLV431BIDBZRG4 datasheet, TLV431BIDBZRG4 pinout, TLV431BIDBZRG4 application, or TLV431BIDBZRG4 equivalent, key selection criteria include reference accuracy over temperature (±4 mV from 0°C to 70°C), ultra-low 80 µA typical cathode current requirement, SC-70 package footprint (2.0 mm × 1.5 mm), and compatibility with optocoupler-based feedback loops in space-constrained AC/DC adapters and industrial power modules.

Technical Context

The TLV431BIDBZRG4 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 threshold) and closed-loop shunt regulation mode without requiring external compensation.

It operates across 0°C to 70°C (C-grade), delivers stable regulation from VKA = 1.24 V to 6 V, and maintains < 0.25 Ω dynamic impedance up to 15 mA cathode current - critical for tight output voltage control in low-headroom, high-efficiency DC-DC converters where traditional TL431 devices cannot function.

Key Specifications

Pinout & Package

TLV431BIDBZRG4 uses the SC-70 (DCK) 6-pin package with 2.0 mm × 1.5 mm body size and 0.5 mm lead pitch. Pin 1 is Cathode, Pin 3 is Anode, Pin 6 is Reference; Pins 2, 4, and 5 are no-connect (NC) terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BIDBZRG4, TLV431BIDBVRG4 offers identical electrical specs but larger SOT-23-5 packaging and substrate pin access, while TLVH431ACDBVRG4 extends voltage range and current capacity at the cost of reduced accuracy and higher minimum cathode current - making TLV431BIDBZRG4 optimal for compact, low-voltage, high-precision shunt regulation.

Availability

TLV431BIDBZRG4 is available at Aetrix Electronics and suitable for isolated flyback SMPSs, on-board voltage clamping, brown-out detection circuits, and optocoupler feedback networks requiring stable component supply, consistent parametric performance, and long-term manufacturability.

Supply support for TLV431BIDBZRG4 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 power management solutions for industrial, automotive, and communications markets.

The TLV431BIDBZRG4 belongs to TI's precision shunt regulator product line, engineered specifically for low-voltage, high-accuracy voltage referencing in space-constrained power systems - extending the TL431 architecture to sub-2 V operation with enhanced thermal stability and miniaturized packaging.

FAQ

What is the reference voltage tolerance of TLV431BIDBZRG4 at 25°C?

The TLV431BIDBZRG4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a VREF range of 1.234 V to 1.246 V. This tight initial accuracy is specified in Section 5.7 of the TI datasheet SLVS139Z and applies exclusively to the TLV431B grade - distinguishing it from TLV431A (±1%) and TLV431 (±1.5%). The tolerance remains valid under recommended operating conditions with IK = 10 mA and VKA = VREF.

Can TLV431BIDBZRG4 operate with cathode-to-anode voltage below 2.5 V?

Yes, TLV431BIDBZRG4 is explicitly designed for low-voltage operation starting at VKA = 1.24 V - the minimum required to forward-bias its internal reference and amplifier. Unlike the TL431 (which requires ≥2.5 V), the TLV431BIDBZRG4 regulates stably down to 1.24 V, enabling use in 1.8 V and 2.5 V systems where headroom is constrained. Operation below 1.24 V results in loss of regulation.

What is the SC-70 package pin configuration for TLV431BIDBZRG4?

The TLV431BIDBZRG4 uses the SC-70 (DCK) 6-pin package with top-view pinout: Pin 1 = CATHODE, Pin 2 = NC (substrate connection, must tie to ANODE or leave open), Pin 3 = ANODE, Pin 4 = NC, Pin 5 = NC, Pin 6 = REF. This configuration is confirmed in Figure 4-5 and Table 4-1 of the TI datasheet SLVS139Z, and differs from SOT-23-3 and SOT-23-5 variants.

How does TLV431BIDBZRG4 behave in open-loop comparator mode?

In open-loop mode, TLV431BIDBZRG4 functions as a comparator with integrated 1.24 V reference: when voltage at the REF pin exceeds VREF, the CATHODE pin pulls low (~1 V saturation); otherwise, it remains high (near VKA). It requires ≥55 µA cathode current to ensure sufficient gain and response speed. This mode eliminates need for external reference and comparator in voltage-monitoring circuits.

Is TLV431BIDBZRG4 compatible with optocoupler-based feedback in flyback converters?

Yes, TLV431BIDBZRG4 is widely used in optocoupler-coupled secondary-side regulation for 3.3 V flyback converters. Its 1.24 V reference enables regulation down to ~2.7 V output (1.24 V + optocoupler LED VF ≈ 2.64 V), and its low 80 µA typical cathode current minimizes loading on the auxiliary winding. TI application note SLUA671 confirms its stability and compensation suitability in UCC28600-based designs.