Texas Instruments TL431CDBVRG4

Overview

TL431CDBVRG4 from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, delivering 2.495 V nominal reference voltage with ±0.5% initial tolerance (B grade), 0.2 Ω typical dynamic impedance, and operation from 0°C to 70°C. It functions as an adjustable 2.5–36 V shunt regulator for secondary-side feedback in isolated flyback converters and replaces discrete Zener diodes in voltage monitoring and error amplification circuits.

For engineers reviewing the TL431CDBVRG4 datasheet, TL431CDBVRG4 pinout, TL431CDBVRG4 application, or TL431CDBVRG4 equivalent, this page provides verified electrical specifications, thermal behavior, real-world use cases, and validated alternative parts - all specific to the TL431CDBVRG4 variant with C-grade temperature range and B-grade accuracy.

Technical Context

The TL431CDBVRG4 implements a three-terminal adjustable shunt regulator architecture with an internal 2.5 V bandgap reference, high-gain transconductance amplifier, and NPN output stage. Its sharp turn-on characteristic and low output impedance enable stable regulation across cathode currents from 1 mA to 100 mA.

It operates exclusively in shunt mode: the REF pin senses voltage relative to ANODE, triggering current sink at the CATHODE when the threshold is exceeded. The SOT-23-3 package (2.90 mm × 1.30 mm) supports surface-mount designs requiring minimal board area and thermal mass.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431CDBZR, TL431CDBVRG4 provides identical performance with RoHS-compliant packaging; compared with TL431BIDBVR, it trades extended temperature range for lower cost and optimized qualification for commercial-grade power supplies.

Availability

TL431CDBVRG4 is available at Aetrix Electronics and suitable for commercial power supplies, isolated DC-DC converters, and voltage supervision circuits requiring stable component supply with full traceability and lifecycle management.

Supply support for TL431CDBVRG4 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 and embedded processing technologies, with decades of expertise in precision reference design and power management ICs.

The TL431 product line delivers pin-compatible, grade-scaled shunt references optimized for cost-sensitive, high-volume power conversion and voltage monitoring applications across consumer, industrial, and computing markets.

FAQ

What is the maximum cathode voltage rating for TL431CDBVRG4?

The absolute maximum cathode-to-anode voltage (VKA) for TL431CDBVRG4 is 37 V, with recommended operating range from Vref (≈2.5 V) to 36 V. Exceeding 37 V risks permanent damage. This rating enables safe use in 24 V and 36 V industrial power rails when configured with appropriate current-limiting resistors.

Does TL431CDBVRG4 require an external capacitor for stability?

TL431CDBVRG4 does not require an external capacitor for basic shunt regulation, but a 1 nF ceramic capacitor between REF and ANODE is recommended when driving capacitive loads (e.g., optocoupler input) to prevent oscillation. The device's 0.2 Ω output impedance inherently damps most feedback loop instabilities.

Can TL431CDBVRG4 be used as a comparator?

Yes - TL431CDBVRG4 functions as a comparator with integrated 2.495 V reference: when voltage at REF exceeds Vref, it sinks current at CATHODE. It is commonly used in overvoltage detection and window comparators, though response time (~1 µs) is slower than dedicated comparators.

What is the thermal resistance (RθJA) of TL431CDBVRG4 in SOT-23-3 package?

The junction-to-ambient thermal resistance (RθJA) for TL431CDBVRG4 in SOT-23-3 package is 206°C/W, measured on a standard 1-inch² FR-4 board with 2 oz copper. At 100 mA cathode current and 36 V VKA, power dissipation reaches 3.6 W - requiring careful thermal layout or derating to stay within 150°C max junction temperature.

How does the reference input current (Iref) of TL431CDBVRG4 affect resistor divider design?

TL431CDBVRG4 draws 2–4 µA into the REF pin, so resistor values in the feedback divider must balance divider current (typically 100× Iref = 200–400 µA) to minimize voltage error while avoiding excessive power loss. For example, a 10 kΩ + 10 kΩ divider at 5 V yields 250 µA current, keeping REF pin error below 0.01%.