Texas Instruments TLV431BQDBZTG4

Overview

TLV431BQDBZTG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 0.5% 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 - widely deployed in isolated flyback secondary-side regulation for 3.3 V power supplies.

For engineers reviewing the TLV431BQDBZTG4 datasheet, TLV431BQDBZTG4 pinout, TLV431BQDBZTG4 application, or TLV431BQDBZTG4 equivalent, key selection criteria include initial VREF accuracy (0.5%), temperature drift over –40°C to 125°C (11 mV), SC-70 package footprint, cathode current capability (up to 15 mA), and stability without output capacitance in closed-loop configurations.

Technical Context

The TLV431BQDBZTG4 implements a three-terminal adjustable shunt reference architecture with an internal bandgap reference and NPN-based error amplifier driving a Darlington sink output stage. Its open-loop mode functions as a comparator with integrated 1.24 V reference; closed-loop operation enables precise voltage or current regulation via resistive feedback from cathode to reference pin.

It operates with ≥1.24 V cathode-to-anode headroom and requires ≥55 µA cathode current to maintain regulation across its full –40°C to 125°C Q-grade temperature range. The device is internally compensated and stable without external output capacitance, though phase margin vs. capacitive load is characterized up to 1 nF for design validation.

Key Specifications

Pinout & Package

TLV431BQDBZTG4 uses the SC-70 (DCK) 6-pin package with exposed substrate pad. Pin 1 is CATHODE (shunt current input), Pin 3 is REF (reference threshold input), and Pin 6 is ANODE (common return). Pins 2, 4, and 5 are NC (no internal connection); Pin 2 is substrate-connected and must be tied to ANODE or left floating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BQDBZTG4, TLV431BIDBZR trades Q-grade temperature support and SC-70 size for SOT-23-3 availability, while TLVH431BQDBZR expands voltage/current range at the cost of reference precision and package miniaturization - making TLV431BQDBZTG4 optimal for space-constrained, high-accuracy automotive or industrial feedback loops.

Availability

TLV431BQDBZTG4 is available at Aetrix Electronics and suitable for isolated flyback regulation, voltage monitoring, Zener replacement, adjustable current sinking, and comparator applications requiring stable component supply across automotive and industrial production cycles.

Supply support for TLV431BQDBZTG4 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, personal electronics, and communications markets.

The TLV431 family is designed as a low-voltage, precision shunt reference platform targeting secondary-side regulation in isolated power supplies and compact voltage reference needs in space- and power-constrained systems.

FAQ

What is the reference voltage tolerance of TLV431BQDBZTG4 at 25°C?

The TLV431BQDBZTG4 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. This tight initial accuracy is specified in Section 5.7 of the TI datasheet SLVS139Z and applies specifically to the TLV431B grade. The 'B' suffix denotes the 0.5% tolerance bin, distinguishing it from TLV431A (±1%) and TLV431 (±1.5%). TLV431BQDBZTG4 maintains this specification across its SC-70 packaging and Q-grade temperature qualification.

What is the operating temperature range for TLV431BQDBZTG4?

TLV431BQDBZTG4 is qualified for operation from –40°C to +125°C, designated by the 'Q' suffix in its part number. This automotive-grade temperature range is confirmed in Section 5.3 (Recommended Operating Conditions) and Section 5.7 (Electrical Characteristics for TLV431B) of the TI datasheet SLVS139Z. The device's V_REF deviation over this full range is specified at 11 mV maximum, supporting use in engine control units, industrial motor drives, and other high-reliability environments where extended thermal performance is mandatory.

Which package does TLV431BQDBZTG4 use, and what are its dimensions?

TLV431BQDBZTG4 uses the SC-70 (DCK) package, measuring 2.0 mm × 1.5 mm - 40% smaller than the SOT-23-3 footprint. This is explicitly stated in the "Package Information" section and Figure 4-5 (DCK package top view) of the TI datasheet SLVS139Z. The DCK package has six pins with pin 1 = CATHODE, pin 3 = REF, pin 6 = ANODE, and pins 2/4/5 as NC (with pin 2 being substrate-connected). The compact size makes TLV431BQDBZTG4 suitable for dense PCB layouts in AC/DC adapters and portable electronics.

Can TLV431BQDBZTG4 replace a Zener diode, and what advantages does it offer?

Yes, TLV431BQDBZTG4 is explicitly positioned as a Zener diode replacement in Section 2 (Applications) and Section 7.3 of the TI datasheet. It offers superior performance: 0.25 Ω typical dynamic impedance (vs. 10–100 Ω for Zeners), 0.5% V_REF tolerance (vs. 5% typical for Zeners), sharp turn-on characteristic, and stable operation without output capacitance. TLV431BQDBZTG4 also supports adjustable output from 1.24 V to 6 V using two resistors - unlike fixed-voltage Zeners - and exhibits only 11 mV V_REF drift over –40°C to 125°C, significantly improving system accuracy and thermal stability.

Does TLV431BQDBZTG4 require an external output capacitor for stability?

No, TLV431BQDBZTG4 is internally compensated and stable without an external output capacitor between cathode and anode - a key feature highlighted in Section 7.3 and Figure 5-19 of the TI datasheet SLVS139Z. This eliminates BOM cost and layout constraints in most applications. However, if an output capacitor is used (e.g., for noise filtering), Figure 5-19–5-21 provide phase margin vs. capacitive load data up to 1 nF to ensure stability. For TLV431BQDBZTG4 in closed-loop configurations like flyback feedback, capacitor-free operation is fully supported and validated.