Texas Instruments TLV431AILPME3

Overview

TLV431AILPME3 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±1% initial tolerance at 25°C, 0.25 Ω typical dynamic impedance, and operation down to 1.24 V cathode-anode voltage. It functions as a programmable Zener replacement in secondary-side feedback loops of isolated 3.3 V flyback converters.

For engineers reviewing the TLV431AILPME3 datasheet, TLV431AILPME3 pinout, TLV431AILPME3 application, or TLV431AILPME3 equivalent, key selection criteria include reference accuracy over temperature (±6 mV from –40°C to 85°C), minimum cathode current (80 µA typical), ultra-low output impedance, TO-92 package compatibility, and open-loop comparator capability with integrated reference.

Technical Context

The TLV431AILPME3 implements a bandgap-referenced error amplifier driving a Darlington sink output stage, enabling precise voltage regulation via external resistor divider feedback between cathode and reference pins. Its internal architecture supports both closed-loop shunt regulation and open-loop comparator operation without external compensation.

It operates with cathode-anode voltage (VKA) from 1.24 V to 6 V and cathode current (IK) from 80 µA to 15 mA, delivering stable reference behavior across industrial temperature range (–40°C to +85°C). The device achieves sharp turn-on characteristics and low thermal drift due to trimmed reference and matched transistor pairs.

Key Specifications

Pinout & Package

TLV431AILPME3 uses the LP (TO-92/TO-226) package: 5.2 mm × 3.68 mm through-hole outline with 3 leads, lead spacing 2.54 mm, compatible with legacy Zener footprints and manual soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431AILPME3, TLV431ACLP trades industrial temperature support for improved accuracy, while TLVH431ILP extends voltage and current capability at the cost of reduced reference stability at low VKA-making TLV431AILPME3 optimal for cost-sensitive, 3.3 V–5 V industrial SMPS designs.

Availability

TLV431AILPME3 is available at Aetrix Electronics and suitable for isolated flyback power supplies, precision voltage monitoring circuits, Zener diode replacements, and comparator-based threshold detection requiring stable component supply and long-term manufacturability.

Supply support for TLV431AILPME3 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 headquartered in Dallas, Texas, designing analog and embedded processing chips for industrial, automotive, and communications markets since 1930.

The TLV431 family was developed to replace fixed-voltage Zener diodes with programmable, low-voltage precision references for next-generation energy-efficient power supplies and compact sensor interfaces.

FAQ

What is the maximum cathode-anode voltage (VKA) for TLV431AILPME3?

The absolute maximum cathode-anode voltage for TLV431AILPME3 is 7 V, but the recommended operating range is 1.24 V to 6 V. Exceeding 6 V risks violating the device's safe operating area and may cause irreversible degradation. Within the 1.24–6 V range, TLV431AILPME3 maintains specified reference accuracy and dynamic impedance performance per its electrical characteristics table.

Can TLV431AILPME3 replace a standard 3.3 V Zener diode directly?

Yes, TLV431AILPME3 can replace a 3.3 V Zener diode in most cases-but requires two external resistors to set the output voltage (e.g., R1 = 10 kΩ, R2 = 5.6 kΩ yields ~3.3 V). Unlike a Zener, it draws only ~0.3 µA at the REF pin and exhibits 0.25 Ω dynamic impedance versus >20 Ω for typical Zeners-delivering significantly better regulation under load variation.

Does TLV431AILPME3 require an output capacitor for stability?

No, TLV431AILPME3 is internally compensated and remains stable without a cathode-to-anode capacitor across its full operating range. However, if a capacitive load >1 nF is placed directly at the cathode node, phase margin may degrade-consult Figure 5-19 in the datasheet to select appropriate series resistance or capacitance for marginal cases.

What is the minimum cathode current needed for regulation in TLV431AILPME3?

The minimum cathode current required for regulation in TLV431AILPME3 is 80 µA typical (max 100 µA over temperature). Below this threshold, the device exits regulation and behaves as an open circuit. This ultra-low IK(min) enables use with high-value feedback resistors or low-current optocouplers where TL431 (1 mA IK(min)) would fail to regulate.

How does TLV431AILPME3 perform as a comparator?

In open-loop configuration, TLV431AILPME3 functions as a comparator with integrated 1.24 V reference: when voltage at the REF pin exceeds 1.24 V, the CATHODE sinks current; below that, it remains high-impedance. Response time is <1 µs with ≥10% overdrive, and output swings from ~1 V (low) to V_CC (high) - ideal for brown-out detection or overvoltage lockout without external components.