Texas Instruments TLVH431AIPK

Overview

TLVH431AIPK from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-89-3 package, featuring 1.24 V reference voltage with ±1% tolerance at 25°C, 100 μA to 70 mA cathode current range, 0.25 Ω typical dynamic impedance, and operation from –40°C to +85°C. It serves as an error amplifier or voltage reference in isolated flyback SMPS feedback loops.

For engineers reviewing the TLVH431AIPK datasheet, TLVH431AIPK pinout, TLVH431AIPK application, or TLVH431AIPK equivalent, key selection criteria include reference accuracy grade (A = 1%), thermal stability over industrial temperature range, cathode voltage headroom down to 1.24 V, and compatibility with optocoupler-based secondary-side regulation circuits.

Technical Context

The TLVH431AIPK implements a precision bandgap reference and high-gain transconductance amplifier in a 3-terminal shunt topology. Its internal architecture forces the REF pin to 1.24 V when sufficient cathode current (≥100 μA) is supplied, enabling closed-loop regulation via external resistor dividers.

It operates in two distinct functional modes: open-loop comparator mode (with integrated 1.24 V reference) and closed-loop shunt regulator mode. Unlike standard linear regulators, it requires no output capacitor for stability but supports capacitive load compensation per Figures 5-15–5-17.

Key Specifications

Pinout & Package

SOT-89-3 package (4.50 mm × 2.50 mm body), surface-mount, thermally enhanced with exposed pad (not electrically connected). Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AIDBZR and TLVH432AIPK, the TLVH431AIPK offers optimal thermal performance in SOT-89 packaging and guaranteed pin compatibility for existing flyback feedback layouts, making it the preferred choice for industrial power supply redesigns requiring reliability and thermal margin.

Availability

TLVH431AIPK is available at Aetrix Electronics and suitable for industrial power supplies, embedded voltage monitoring systems, and isolated DC-DC converters requiring stable component supply across extended temperature ranges.

Supply support for TLVH431AIPK 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, embedded processing, and power management solutions, with leadership in precision analog ICs and industrial-grade components.

The TLVH431 family was designed specifically for low-voltage shunt regulation and secondary-side feedback in isolated switch-mode power supplies, targeting industrial, telecom, and computing applications demanding accuracy, thermal stability, and compact packaging.

FAQ

What is the reference voltage tolerance of TLVH431AIPK at 25°C?

The TLVH431AIPK has a reference voltage tolerance of ±1% at 25°C, corresponding to a 1.24 V nominal reference with a range of 1.228 V to 1.252 V. This A-grade specification is confirmed in Section 5.6 of the TI SLVS555N datasheet and applies across all operating conditions unless otherwise noted. The TLVH431AIPK maintains this accuracy over its full industrial temperature range of –40°C to +85°C.

Can TLVH431AIPK be used in place of TL431 in existing designs?

The TLVH431AIPK is not a direct replacement for TL431 due to its lower 1.24 V reference voltage (vs. 2.5 V), different minimum cathode current (100 μA vs. 1 mA), and SOT-89-3 package. While functionally similar as a shunt regulator, circuit redesign is required to adjust feedback resistor values and verify biasing. TLVH431AIPK enables operation in sub-2.5 V systems where TL431 cannot regulate, but pinout and thermal characteristics differ significantly.

What is the maximum cathode voltage rating for TLVH431AIPK?

The absolute maximum cathode-to-anode voltage (V_KA) for TLVH431AIPK is 20 V, as specified in Section 5.1 of the TI SLVS555N datasheet. For continuous operation, the recommended maximum cathode voltage is 18 V per Section 5.3. Exceeding 20 V risks permanent damage, and operation above 18 V should be avoided in production designs to ensure reliability and lifetime compliance.

Does TLVH431AIPK require an output capacitor for stability?

No, TLVH431AIPK is internally compensated and does not require an output capacitor between cathode and anode for basic stability. However, if a capacitive load is added (e.g., for noise filtering), Figures 5-15 through 5-17 in the datasheet provide phase margin guidance to select appropriate capacitance values (typically ≤10 nF) and avoid oscillation. Stability must be verified experimentally when adding external capacitance.

How does the TLVH431AIPK pinout differ from TLVH432AIPK?

The TLVH431AIPK uses Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF in its SOT-89-3 package. In contrast, TLVH432AIPK has Pin 1 = REF, Pin 2 = ANODE, Pin 3 = CATHODE - a reversed pinout that makes them electrically identical but mechanically incompatible. Using TLVH432AIPK in a TLVH431AIPK footprint will result in incorrect connections and circuit failure; PCB layout must be revised to match the alternate pin assignment.