Texas Instruments TLV431BQDBVTG4

Overview

TLV431BQDBVTG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, 0.5% initial tolerance at 25°C, and operation from 1.24 V to 6 V output range. It delivers 0.25 Ω typical dynamic impedance, 80 µA typical cathode current, and supports secondary-side regulation in isolated flyback SMPSs.

For engineers reviewing the TLV431BQDBVTG4 datasheet, TLV431BQDBVTG4 pinout, TLV431BQDBVTG4 application, or TLV431BQDBVTG4 equivalent, key selection criteria include reference accuracy over temperature (±11 mV from –40°C to 125°C), ultra-small SC-70 package footprint, open-loop comparator capability with integrated reference, and compatibility with optocoupler-based feedback in 3.3 V systems.

Technical Context

The TLV431BQDBVTG4 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 ±0.5% at 25°C and exhibits 11 mV max deviation across –40°C to 125°C (Q-grade).

It operates in two functional modes: closed-loop shunt regulation (with resistive feedback from cathode to REF) and open-loop comparator mode (REF driven externally). Minimum cathode current for regulation is 55–100 µA depending on temperature, and dynamic impedance remains stable at ≤0.4 Ω up to 15 mA cathode current.

Key Specifications

Pinout & Package

TLV431BQDBVTG4 is housed in a 6-pin SC-70 (DCK) package with 2.0 mm × 1.5 mm body size and gull-wing leads. Pin 1 is CATHODE, Pin 3 is REF, 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 TLV431BIDBVR, TLV431BQDBVTG4 saves 40% PCB area and provides unused pins for grounding or noise control; compared with TLVH431BQDBVR, it offers tighter low-current regulation and lower quiescent power but is limited to 6 V maximum VKA.

Availability

TLV431BQDBVTG4 is available at Aetrix Electronics and suitable for isolated flyback power supplies, precision voltage monitoring circuits, and compact shunt regulator designs requiring stable component supply across automotive, industrial, and telecom end equipment.

Supply support for TLV431BQDBVTG4 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 for industrial, automotive, and communications markets.

The TLV431 family was designed as a low-voltage, precision alternative to the TL431, targeting space- and power-constrained applications requiring 1.24 V reference and operation down to 1.24 V cathode-anode voltage.

FAQ

What is the reference voltage tolerance of TLV431BQDBVTG4 at 25°C?

The TLV431BQDBVTG4 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 specifically to the TLV431B grade. The Q suffix denotes qualification for –40°C to 125°C operation, and the tolerance holds across that full range with ±11 mV total deviation.

Can TLV431BQDBVTG4 replace a standard Zener diode in low-voltage circuits?

Yes, TLV431BQDBVTG4 can directly replace low-voltage Zener diodes (e.g., 1.2 V or 1.5 V types) with superior performance: sharper turn-on, 0.25 Ω dynamic impedance versus typical Zener impedance >10 Ω, and 0.5% initial accuracy versus ±5% Zener tolerance. Its 1.24 V reference and ability to operate down to 1.24 V cathode-anode voltage make TLV431BQDBVTG4 especially effective in 1.8 V and 2.5 V systems where conventional Zeners exhibit poor regulation.

What is the minimum cathode current required for regulation in TLV431BQDBVTG4?

The minimum cathode current required for regulation in TLV431BQDBVTG4 is 55 µA at 25°C and up to 100 µA across the full –40°C to 125°C temperature range, as specified in Section 5.7 of the datasheet. This low IK(min) enables use with high-value feedback resistors (e.g., 1 MΩ), reducing standby power consumption in battery-powered applications while maintaining regulation integrity.

Does TLV431BQDBVTG4 require an output capacitor for stability?

No, TLV431BQDBVTG4 is internally compensated and stable without an output capacitor between cathode and anode in standard shunt regulator configurations. Section 7.3 of the datasheet confirms this feature. However, if an output capacitor is added for filtering, Figure 5-19 provides phase margin vs capacitive load data to guide selection - stability margins degrade above ~1 nF for VKA = 1.25 V, so capacitor use must be validated per application conditions.

How does the SC-70 package of TLV431BQDBVTG4 compare to SOT-23-3 variants?

The SC-70 (DCK) package of TLV431BQDBVTG4 measures 2.0 mm × 1.5 mm, offering a 40% smaller footprint than the SOT-23-3 (DBZ) variant (2.92 mm × 2.37 mm). While both are surface-mount, the SC-70 has 6 pins (CATHODE, REF, ANODE, and three NC) versus 3 pins on SOT-23-3, enabling enhanced noise immunity via grounded NC pins and flexible layout routing - though it requires more precise placement during reflow.