Diodes Incorporated TLV431BQFTA

Overview

TLV431BQFTA from Diodes Incorporated is an automotive-grade, adjustable 1.24V shunt voltage reference IC in SOT-23 package, delivering 0.5% initial reference voltage tolerance at +25°C, ±11mV max VREF deviation over –40°C to +125°C, and 20mA max cathode current. It replaces Zener diodes in precision feedback loops for DC-DC converters, battery management systems, and automotive power supplies.

For engineers reviewing the TLV431BQFTA datasheet, TLV431BQFTA pinout, TLV431BQFTA application, or TLV431BQFTA equivalent, key selection criteria include its AEC-Q100 Grade 1 qualification, low 80µA minimum cathode current requirement, 0.25Ω typical dynamic output impedance, and compatibility with external resistor networks for 1.24V–18V adjustable output configuration.

Technical Context

The TLV431BQFTA operates as a three-terminal shunt regulator where the REF pin senses a resistive divider, and the device sinks cathode current to maintain precise VREF across the divider. Its internal bandgap reference and error amplifier enable stable regulation without external compensation.

It supports operation from –40°C to +125°C ambient, with guaranteed 0.5% VREF accuracy at +25°C and <11mV total drift over full temperature range. The SOT-23 package provides thermal resistance of 380°C/W and 330mW power dissipation capability at TA = +25°C.

Key Specifications

Pinout & Package

TLV431BQFTA is housed in a RoHS-compliant, lead-free SOT-23 surface-mount package (JEDEC TO-236AB), with 3 active terminals and thermal pad connected to pin 2 (Anode) per mechanical layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BIDBVR, TLV431BQFTA adds AEC-Q100 compliance and PPAP readiness for automotive deployment; compared with TLVH431BQDBVR, it trades 0.25% tolerance and 18V VKA headroom for lower unit cost and established qualification in legacy vehicle platforms.

Availability

TLV431BQFTA is available at Aetrix Electronics and suitable for automotive power management, battery monitoring, and precision feedback applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for TLV431BQFTA 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability components for automotive, industrial, and computing markets.

The TLV431Q series was designed specifically for AEC-Q100-compliant shunt reference applications-emphasizing temperature stability, low cathode current, and drop-in Zener replacement capability in safety-critical automotive subsystems.

FAQ

What is the minimum cathode current required for regulation at +125°C?

The TLV431BQFTA requires a minimum cathode current of 100 µA at +125°C to maintain regulation, as specified in the Electrical Characteristics table under IKMIN at –40°C to +125°C. This value exceeds the 80 µA typical at +25°C and must be accounted for when sizing the external series resistor in high-temperature environments.

Can TLV431BQFTA replace a standard 3.3V Zener diode directly?

No-TLV431BQFTA is a 3-terminal adjustable shunt regulator, not a 2-terminal Zener. To replace a 3.3V Zener, connect a resistor divider (R1 = 16.2kΩ, R2 = 10kΩ) between cathode and anode, with REF tied to the divider midpoint. This configures VOUT = 1.24V × (1 + R1/R2) ≈ 3.3V, achieving superior accuracy and temperature stability versus a 5% Zener.

Is pin 2 (Anode) required to be grounded in all applications?

No-pin 2 (Anode) serves as the common return path and may be connected to system ground, left floating, or tied to another low-impedance node depending on circuit topology. In SOT-23, it is internally connected to the die substrate; grounding improves thermal performance and noise immunity, but floating is permissible in isolated feedback configurations per Diodes' recommended layout guidance.

How does the 0.5% VREF tolerance impact output voltage accuracy in a 5V adjustable supply?

When configured for 5V output using R1/R2, the 0.5% VREF tolerance contributes ±0.5% × (5V / 1.24V) ≈ ±2.0% uncertainty to the final output. Combined with resistor tolerance (e.g., ±1% each), total output error remains within ±3.5%, significantly better than a typical 5% Zener-based solution and sufficient for most automotive MCU and sensor supply requirements.