Texas Instruments TL431CLPM5

Overview

TL431CLPM5 from onsemi is a three-terminal programmable shunt voltage reference IC operating as a precision zener replacement with 2.495 V nominal reference voltage, ±2.2% initial tolerance, 0.22 Ω typical dynamic impedance, and 1.0–100 mA sink current capability. It enables adjustable output voltages from 2.5 V to 36 V in power supply feedback loops, voltage monitors, and optocoupler-driven isolated regulators.

For engineers reviewing the TL431CLPM5 datasheet, TL431CLPM5 pinout, TL431CLPM5 application, or TL431CLPM5 equivalent, key selection criteria include its TO-92 (LP) package, 0°C to +70°C operating range, 2.2% reference tolerance, low temperature coefficient (50 ppm/°C typical), and compatibility with standard shunt regulator design practices including stability analysis for capacitive loads.

Technical Context

The TL431CLPM5 implements an internal 1.78 V bandgap reference with transconductance amplifier and output stage, enabling precise regulation via external resistor divider. Its operation relies on feedback between cathode, anode, and reference pins to maintain V_ref = 2.495 V at the reference input when cathode-anode voltage exceeds V_ref.

Stability is governed by load capacitance and cathode current; boundary conditions show instability risk above ~10 nF at 10 mA IK without series resistance. The device exhibits low noise (≈10 µV/√Hz at 10 kHz) and high open-loop gain (>56 dB DC), supporting accurate closed-loop control in analog and switching power applications.

Key Specifications

Pinout & Package

TL431CLPM5 uses the TO-92 (Case 29, LP suffix) plastic package - a 3-pin through-hole package with 0.1" lead spacing, compatible with standard PCB mounting and wave soldering. Pin 1 is Reference, Pin 2 is Anode, Pin 3 is Cathode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431BCLPM5 and TL431ACLPM5, the TL431CLPM5 offers the most cost-effective solution for commercial-grade power supplies where ±2.2% reference error remains within overall system tolerance budgets, especially in cost-sensitive consumer adapters and auxiliary bias rails.

Availability

TL431CLPM5 is available at Aetrix Electronics and suitable for AC-DC adapters, overvoltage protection circuits, LED constant-current drivers, and voltage-monitoring systems requiring stable component supply across production volumes.

Supply support for TL431CLPM5 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, and consumer markets.

The TL431 series belongs to onsemi's precision analog portfolio, designed specifically for programmable shunt regulation in power supply feedback, voltage monitoring, and current-sinking applications demanding high accuracy and thermal stability.

FAQ

What is the reference voltage tolerance of TL431CLPM5 at 25°C?

The TL431CLPM5 has a reference voltage tolerance of ±2.2% at 25°C, meaning its nominal 2.495 V reference falls within 2.438 V to 2.552 V under standard test conditions. This tolerance is specified in the Electrical Characteristics table for the 'C' grade variant and applies across the full commercial temperature range (0°C to +70°C).

Can TL431CLPM5 be used in place of a Zener diode?

Yes, TL431CLPM5 serves as a precision replacement for Zener diodes in shunt regulator applications. Unlike passive Zeners, it delivers superior temperature stability (50 ppm/°C typical), lower dynamic impedance (0.22 Ω), and programmable output voltage (2.5–36 V) using two external resistors - making it ideal for feedback networks in switching regulators and precision voltage monitors.

What is the maximum cathode-to-anode voltage rating for TL431CLPM5?

The absolute maximum cathode-to-anode voltage (V_KA) for TL431CLPM5 is 37 V, as defined in the Maximum Ratings table. Operation beyond this voltage risks permanent damage. For reliable long-term use, the recommended operating range limits V_KA to 36 V maximum, aligning with standard shunt regulator design margins.

Does TL431CLPM5 require external compensation for stability?

Yes, TL431CLPM5 stability depends on load capacitance and cathode current. The datasheet provides stability boundary curves (Figure 15) showing that >10 nF capacitive load at 10 mA IK may cause oscillation. A series resistor (e.g., 10–100 Ω) with the capacitor or reduction in C_L is often required to ensure phase margin >45° in feedback applications like optocoupler interfaces.

What package type does TL431CLPM5 use?

TL431CLPM5 uses the TO-92 plastic package (Case 29, LP suffix), a 3-pin through-hole package with leads spaced 0.1" apart. It is marked "TL431CLP" and complies with Pb-free and RoHS requirements. This package supports manual assembly, wave soldering, and is widely used in cost-sensitive commercial power applications.