Texas Instruments TL431ILPE3

Overview

TL431ILPE3 from Texas Instruments is a precision programmable shunt voltage reference IC with 1% initial tolerance at 25°C, adjustable output from 2.495 V to 36 V, and operation across −40°C to 85°C. It delivers 0.2 Ω typical dynamic impedance, 1–100 mA sink-current capability, and low output noise-enabling accurate feedback in isolated DC-DC converters and industrial power supplies.

For engineers reviewing the TL431ILPE3 datasheet, TL431ILPE3 pinout, TL431ILPE3 application, or TL431ILPE3 equivalent, this page provides verified electrical specifications, thermal performance data, package-specific pin functions, real-world use cases in AC/DC and servo drive systems, and two validated alternative parts for design flexibility.

Technical Context

The TL431ILPE3 implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference voltage source, and output transistor. Its REF pin senses voltage relative to ANODE, triggering cathode current modulation to maintain precise regulation between V_REF (≈2.495 V) and 36 V via external resistor dividers.

It features sharp turn-on characteristics, low temperature drift (14 mV over −40°C to 85°C), and stable operation up to 100 mA sink current. The I-grade temperature range and 1% accuracy make it suitable for industrial AC/DC supplies and servo control modules where long-term stability under thermal stress is critical.

Key Specifications

Pinout & Package

TL431ILPE3 is supplied in the PDIP-8 (Plastic Dual In-line Package, 9.50 mm × 6.35 mm) with standard through-hole mounting. Pin 1 is CATHODE, Pin 2 is REF, Pin 3 is ANODE; Pins 4–8 are NC (no internal connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ILPE3, TL431ACDR offers identical electrical performance in a surface-mount package requiring layout adaptation, while TLVH431BIDBVR trades voltage range and current capacity for higher accuracy-making each viable only within distinct design constraints.

Availability

TL431ILPE3 is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC supplies, and servo drive control modules requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for TL431ILPE3 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 analog ICs and power management solutions.

The TL431 family was designed as a pin-compatible, cost-effective replacement for Zener diodes in feedback regulation-targeting industrial, computing, and motor control applications demanding accuracy, stability, and wide operating margins.

FAQ

What is the reference voltage tolerance of TL431ILPE3 at 25°C?

The TL431ILPE3 has a 1% initial reference voltage tolerance at 25°C, corresponding to a nominal V_REF of 2.495 V with a range of 2.470 V to 2.520 V. This A-grade accuracy is specified per TI's SLVS543S datasheet Section 6.8 and applies across the full operating temperature range of −40°C to +85°C.

Can TL431ILPE3 be used in place of a Zener diode?

Yes, TL431ILPE3 is explicitly designed as a superior replacement for Zener diodes in voltage regulation applications. Its active circuitry provides sharper turn-on, lower dynamic impedance (0.2 Ω vs typical Zener >10 Ω), and adjustable output (2.495 V–36 V), making it ideal for precision feedback in switching power supplies where Zeners lack stability and accuracy.

What is the maximum cathode voltage rating for TL431ILPE3?

The absolute maximum cathode voltage (V_{K A}) for TL431ILPE3 is 37 V, with recommended operation up to 36 V. Exceeding 37 V risks permanent damage. This rating is defined in Section 6.1 of the TI SLVS543S datasheet and applies regardless of current level or temperature condition.

Does TL431ILPE3 require external capacitors for stability?

TL431ILPE3 does not require mandatory external capacitors but benefits from careful layout and optional small ceramic capacitors (e.g., 100 pF–1 nF) near the REF pin to suppress high-frequency noise. Stability boundaries depend on load capacitance and cathode current-see Figure 6-16 in the datasheet for oscillation risk zones.

How is the output voltage set on TL431ILPE3?

The output voltage of TL431ILPE3 is set using two external resistors forming a voltage divider between cathode and anode, with the REF pin connected to the divider midpoint. When the divided voltage reaches ≈2.495 V, the device sinks current to regulate the cathode voltage-enabling precise, resistor-programmable outputs from 2.495 V to 36 V.