Texas Instruments TL431CLPME3

Overview

TL431CLPME3 from Texas Instruments is a precision programmable shunt voltage reference IC with 2.495 V nominal reference voltage, ±0.5% initial tolerance at 25°C (B-grade), and operation across −40°C to 125°C. It delivers 1 mA to 100 mA sink current, features 0.2 Ω typical dynamic impedance, and supports adjustable output from 2.5 V to 36 V using two external resistors-commonly used in feedback loops of isolated DC/DC converters and AC/DC power supplies.

For engineers reviewing the TL431CLPME3 datasheet, TL431CLPME3 pinout, TL431CLPME3 application, or TL431CLPME3 equivalent, key selection criteria include reference accuracy over temperature, cathode current capability, dynamic impedance stability, and compatibility with SOT-23-3 layout constraints in space-constrained power regulation designs.

Technical Context

The TL431CLPME3 implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, bandgap reference, and NPN output stage. Its sharp turn-on characteristic and low output impedance enable Zener diode replacement in closed-loop regulation circuits where precise voltage thresholding and stable error amplification are required.

It operates as a voltage-controlled current sink: the REF pin senses voltage relative to ANODE, and when that voltage exceeds Vref (2.495 V), the CATHODE draws current to maintain regulation. The device is characterized for Q-temp grade (−40°C to 125°C) and specified with VI(dev) ≤ 34 mV over full temperature range.

Key Specifications

Pinout & Package

TL431CLPME3 is housed in a SOT-23-3 package (2.90 mm × 1.30 mm), with gull-wing leads and bottom-side thermal pad. Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF - no internal connection to substrate; ANODE serves as common reference node and ground return path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431CDBZR, TL431CLPME3 offers identical performance but distinct tape-and-reel packaging and traceability; versus AS431ARTDT-33, TL431CLPME3 provides full 2.5–36 V adjustability, tighter 0.5% tolerance, and guaranteed operation up to 125°C-critical for high-reliability power systems.

Availability

TL431CLPME3 is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC, and notebook PC power adapter designs requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for TL431CLPME3 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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability components.

The TL431 product line was designed for precision voltage regulation in isolated and non-isolated power conversion systems, targeting applications demanding stable, low-drift, and easily configurable shunt references.

FAQ

What is the reference voltage tolerance of TL431CLPME3 at 25°C?

The TL431CLPME3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to the B-grade specification. This means its nominal 2.495 V reference falls within 2.483 V to 2.507 V at room temperature, enabling high-accuracy feedback in regulated power supplies without external trimming.

Does TL431CLPME3 support operation at 125°C?

Yes, TL431CLPME3 is rated for operation from −40°C to +125°C (Q-temp grade). Its electrical characteristics-including reference voltage deviation (≤34 mV) and dynamic impedance-are specified across this full range, making it suitable for under-hood automotive and industrial motor drive applications.

What is the minimum cathode current required for regulation in TL431CLPME3?

The TL431CLPME3 requires a minimum cathode current of 0.4 mA to maintain regulation, with typical values between 0.4 mA and 0.7 mA depending on temperature and operating conditions. This low Imin enables stable operation with high-value feedback resistors and low-power standby modes.

Can TL431CLPME3 replace a Zener diode in power supply designs?

Yes, TL431CLPME3 is explicitly designed as a superior replacement for Zener diodes in voltage regulation applications. Its sharp turn-on characteristic, adjustable output (2.5 V to 36 V), low 0.2 Ω dynamic impedance, and tight 0.5% tolerance provide significantly better accuracy, stability, and design flexibility than discrete Zeners.

What package type is used for TL431CLPME3?

TL431CLPME3 uses the SOT-23-3 surface-mount package (2.90 mm × 1.30 mm body size). Pin 1 is CATHODE, Pin 2 is ANODE, and Pin 3 is REF-matching the standard TL431 pinout for drop-in compatibility in existing SOT-23-3 layouts.