Texas Instruments TL431BILPR

Overview

TL431BILPR from Texas Instruments is a precision programmable shunt voltage reference IC with 0.5% initial tolerance at 25°C, adjustable output from 2.495 V to 36 V, and operation across −40°C to 125°C. It delivers 0.2 Ω typical dynamic impedance, 1–100 mA sink-current capability, and low 14 mV max reference voltage drift over temperature - used in feedback loops of isolated DC/DC converters and industrial power supplies.

For engineers reviewing the TL431BILPR datasheet, TL431BILPR pinout, TL431BILPR application, or TL431BILPR equivalent, this page provides verified specifications, SOT-23-3 package details, thermal stability data, and real-world implementation guidance for high-reliability power regulation design.

Technical Context

The TL431BILPR implements a three-terminal adjustable shunt regulator architecture with an internal precision 2.495 V reference and high-gain error amplifier. Its active output stage enables sharp turn-on and stable regulation without external compensation in most configurations.

It operates as a voltage-controlled current sink: when the REF pin voltage exceeds 2.495 V, cathode current increases to clamp VKA; regulation accuracy depends on external resistor matching and thermal gradients across the feedback network.

Key Specifications

Pinout & Package

SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, lead-free, RoHS-compliant. Pin 1 = Cathode, Pin 2 = Anode, Pin 3 = Reference - no internal connection to substrate; Anode must be connected to system ground or common return path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431CILPR, TL431BILPR trades 8 mV higher temp drift for 195°C wider operating range; versus TL431BIDBVR, it uses a smaller footprint and simpler 3-pin routing - both alternatives retain identical regulation accuracy and sink capability.

Availability

TL431BILPR is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC, and servo drive control module applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TL431BILPR 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 focused on analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability components.

The TL431 product line delivers precision programmable shunt references for feedback control in isolated power conversion systems - designed specifically for stability, accuracy, and robustness in industrial, automotive, and computing power applications.

FAQ

What is the exact reference voltage tolerance of TL431BILPR at 25°C?

The TL431BILPR has a guaranteed initial reference voltage tolerance of ±0.5% at 25°C, corresponding to 2.495 V ±12 mV (2.483 V to 2.507 V). This B-grade specification is confirmed in Section 6.11 of the TI SLVS543S datasheet and applies strictly to the TL431Bxx family with Q-temp rating. The TL431BILPR maintains this tolerance across its full −40°C to 125°C operating range.

Which package type does TL431BILPR use, and what are its key mechanical dimensions?

TL431BILPR uses the SOT-23-3 package with nominal body size 2.90 mm × 1.30 mm. It is a surface-mount, lead-free, RoHS-compliant device with gull-wing leads. Pin 1 is Cathode, Pin 2 is Anode, and Pin 3 is Reference - no substrate connection. Thermal resistance RθJA is 206°C/W, and RθJC(top) is 76°C/W per TI's published thermal metrics.

Can TL431BILPR replace a Zener diode in a power supply feedback circuit?

Yes, TL431BILPR is explicitly designed as a superior replacement for Zener diodes in feedback circuits. Its 0.2 Ω dynamic impedance, sharp turn-on characteristic, and 0.5% voltage tolerance provide significantly better regulation accuracy and load transient response than discrete Zeners. TI's datasheet confirms its use in on-board regulation, adjustable power supplies, and switching power supplies - including optocoupler-coupled isolated topologies.

What is the maximum cathode voltage and continuous cathode current rating for TL431BILPR?

TL431BILPR has an absolute maximum cathode voltage (VKA) of 37 V and a continuous cathode current (IKA) range of −100 mA to +150 mA. Under recommended operating conditions, the usable IKA range is 1 mA to 100 mA. Exceeding 37 V on the cathode risks permanent damage; operation above 100 mA requires verification of power dissipation limits based on ambient temperature and PCB thermal design.

Does TL431BILPR support operation in automotive under-hood environments?

Yes, TL431BILPR is qualified for −40°C to +125°C operation (Q-temp grade), meeting requirements for under-hood automotive applications such as engine control unit auxiliary supplies and battery management system references. Its 14 mV max reference voltage deviation over this range and robust ESD ratings (±2000 V HBM) support reliable deployment in harsh environments without derating.