Texas Instruments TL431ACDBVTG4

Overview

TL431ACDBVTG4 from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, delivering 2.47–2.52 V reference voltage (±1% initial tolerance at 25°C), 0.2 Ω typical dynamic impedance, and sink-current capability from 1 mA to 100 mA. It operates across −40°C to 85°C and serves as an adjustable voltage reference or Zener diode replacement in secondary-side regulation of flyback SMPSs.

For engineers reviewing the TL431ACDBVTG4 datasheet, TL431ACDBVTG4 pinout, TL431ACDBVTG4 application, or TL431ACDBVTG4 equivalent, key selection factors include its A-grade 1% Vref accuracy, temperature-stable VI(dev) ≤14 mV over full range, low Iref (2–4 µA), minimal Imin (0.4–0.6 mA), and compatibility with standard resistor-divider feedback networks in isolated power supplies.

Technical Context

The TL431ACDBVTG4 implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference, and output transistor. Its REF pin senses voltage relative to ANODE, triggering cathode current sink when input exceeds Vref - enabling precise closed-loop regulation without external op-amps.

It features sharp turn-on characteristics and low 0.2 Ω output impedance, supporting stable operation under varying load and line conditions. The device is characterized for industrial temperature range (−40°C to 85°C) and rated for cathode voltages up to 36 V with continuous sink current up to 100 mA.

Key Specifications

Pinout & Package

SOT-23-3 package (2.90 mm × 1.30 mm body size), surface-mount, lead-free and RoHS-compliant per DBVTG4 suffix.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR, TL431ACDBVTG4 offers identical functionality with optimized logistics handling; versus TL431AIDBZR, it provides tighter VI(dev) (≤14 mV vs ≤34 mV) at the cost of reduced max operating temperature (85°C vs 125°C), making it preferable for industrial-grade stability-critical designs.

Availability

TL431ACDBVTG4 is available at Aetrix Electronics and suitable for industrial power supplies, isolated DC-DC converters, and precision analog monitoring systems requiring stable component supply with consistent parametric performance across production batches.

Supply support for TL431ACDBVTG4 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 decades of heritage in precision reference design.

The TL431 product line delivers programmable shunt references for feedback, regulation, and monitoring in power conversion and analog signal chains - engineered for accuracy, thermal stability, and broad application interoperability.

FAQ

What is the reference voltage tolerance of TL431ACDBVTG4 at 25°C?

The TL431ACDBVTG4 has an initial reference voltage tolerance of ±1% at 25°C, corresponding to a Vref range of 2.47 V to 2.52 V. This A-grade specification is confirmed in Section 7.8 of the official TI datasheet SLVS543P, and applies specifically to the AC variant in SOT-23-3 packaging. The tolerance remains stable across operating conditions due to internal trimming.

Can TL431ACDBVTG4 replace a Zener diode in a 12 V regulator circuit?

Yes, TL431ACDBVTG4 can directly replace a Zener diode in a 12 V regulator circuit when configured with appropriate external resistors (e.g., R1 = 3.9 kΩ, R2 = 1 kΩ). Its 2.5 V reference, sharp turn-on, and 0.2 Ω dynamic impedance provide superior regulation accuracy (<1%) and lower temperature drift than typical Zeners. The TL431ACDBVTG4 also supports higher sink current (up to 100 mA) without derating.

What is the maximum cathode-to-anode voltage rating for TL431ACDBVTG4?

The absolute maximum cathode-to-anode voltage (VKA) for TL431ACDBVTG4 is 37 V, with recommended operating range from Vref (≈2.5 V) to 36 V. This rating is specified in Section 7.1 of the TI datasheet SLVS543P and enables safe use in 24 V and 36 V industrial power rails, including flyback SMPS secondary-side feedback circuits where cathode connects to transformer output.

Does TL431ACDBVTG4 require an external capacitor for stability?

TL431ACDBVTG4 does not require an external capacitor for basic shunt regulation, but a 1 nF ceramic capacitor between CATHODE and ANODE is recommended in noisy environments or high-impedance feedback networks to suppress RF oscillation. Stability depends on loop gain and external resistor values; TI Application Report SLVA299 confirms this guideline applies specifically to SOT-23-3 variants like TL431ACDBVTG4.

How does the temperature drift of TL431ACDBVTG4 compare to the standard-grade TL431?

TL431ACDBVTG4 exhibits ≤14 mV total reference voltage deviation (VI(dev)) over −40°C to 85°C, whereas standard-grade TL431 (no suffix) shows up to 25 mV drift in same conditions. This 44% improvement stems from A-grade trimming and tighter process control, directly enhancing long-term output stability in industrial applications - a distinction verified in Tables 7.5–7.13 of SLVS543P.