Texas Instruments TL431AQDBZRG4

Overview

TL431AQDBZRG4 from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, featuring 1% initial reference voltage tolerance at 25°C, −40°C to +125°C operating temperature range, and 0.2 Ω typical dynamic impedance. It delivers stable 2.47–2.52 V reference output adjustable up to 36 V via external resistors and is widely used in isolated feedback loops of AC/DC adapters and industrial power supplies.

For engineers reviewing the TL431AQDBZRG4 datasheet, TL431AQDBZRG4 pinout, TL431AQDBZRG4 application, or TL431AQDBZRG4 equivalent, this page provides verified electrical specifications, thermal performance data, pin-level functional roles, automotive-grade temperature stability metrics, and validated alternative options for high-reliability power regulation designs.

Technical Context

The TL431AQDBZRG4 implements a three-terminal adjustable shunt regulator architecture with an internal precision 2.495 V bandgap reference, error amplifier, and NPN output stage. Its Q-grade rating confirms full −40°C to +125°C operation with ≤34 mV total reference voltage deviation across temperature.

It operates as a two-resistor-programmable voltage sink: REF pin senses voltage divider output, ANODE serves as common return (typically ground), and CATHODE sinks current to regulate VKA. No external compensation is required for basic configurations, though stability depends on load capacitance and cathode current per Figure 6-18.

Key Specifications

Pinout & Package

SOT-23-3 package (2.90 mm × 1.30 mm body size) with gull-wing leads; RoHS-compliant, Pb-free, green molding compound.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431AQDBZRG4, TL431ACDBZR sacrifices automotive temperature range for lower cost, while TL431BQDBZR trades 0.5% initial accuracy for improved baseline precision-both retain identical SOT-23-3 footprint and functional compatibility.

Availability

TL431AQDBZRG4 is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and notebook PC adapter designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TL431AQDBZRG4 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 leader specializing in analog, embedded processing, and power management technologies with over 90 years of innovation history.

The TL431 product line delivers precision programmable shunt references for feedback regulation in isolated and non-isolated power converters, targeting high-reliability industrial, automotive, and computing applications.

FAQ

What is the reference voltage tolerance of TL431AQDBZRG4 at 25°C?

The TL431AQDBZRG4 has a 1% initial reference voltage tolerance at 25°C, meaning its V_ref falls within 2.47 V to 2.52 V under nominal conditions. This A-grade specification is confirmed in Section 6.10 of the TI datasheet SLVS543S and applies specifically to the Q-temp variant. The TL431AQDBZRG4 maintains this accuracy across its full −40°C to +125°C operating range with ≤34 mV total deviation.

What package type does TL431AQDBZRG4 use and what are its key mechanical dimensions?

TL431AQDBZRG4 uses the SOT-23-3 surface-mount package with nominal body dimensions of 2.90 mm × 1.30 mm. It features gull-wing leads, RoHS compliance, and Pb-free green molding compound. Pin 1 is REF, Pin 2 is CATHODE, and Pin 3 is ANODE - matching the standard TL431 DBZ pinout shown in Figure 5-1 of the datasheet. Thermal resistance R_θJA is 206°C/W.

How does TL431AQDBZRG4 differ from standard TL431C or TL431I variants?

TL431AQDBZRG4 combines A-grade (1%) initial accuracy with Q-grade (−40°C to +125°C) temperature rating, distinguishing it from TL431C (C-temp, 0°C–70°C) and TL431I (I-temp, −40°C–85°C). Its 34 mV max reference voltage deviation over temperature exceeds TL431C's 16 mV but matches TL431I's spec. All share identical SOT-23-3 pinout and core electrical behavior, making TL431AQDBZRG4 the only option rated for full automotive under-hood operation with 1% accuracy.

Can TL431AQDBZRG4 replace a Zener diode in voltage regulation circuits?

Yes - TL431AQDBZRG4 is explicitly designed as a superior replacement for Zener diodes in shunt regulation applications. Its active error amplifier delivers sharper turn-on, lower dynamic impedance (0.2 Ω vs. typical Zener's >5 Ω), programmable output (2.5 V to 36 V), and far better temperature stability (≤34 mV drift vs. Zener's >50 mV). It requires only two external resistors and operates reliably down to 0.4 mA cathode current.

What is the maximum cathode current rating for TL431AQDBZRG4 and how is it thermally limited?

TL431AQDBZRG4 supports continuous cathode current from 0.4 mA (minimum for regulation) up to 100 mA. Absolute maximum rating is 150 mA, but sustained operation above 100 mA risks exceeding the 150°C junction limit due to its 206°C/W junction-to-ambient thermal resistance in SOT-23-3. At 100 mA and 25°C ambient, power dissipation reaches 2.5 W × 0.1 A = 0.25 W, raising junction temperature by ~51.5°C - remaining safely within limits.