Texas Instruments TLVH431IPKG3

Overview

TLVH431IPKG3 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±0.5% initial tolerance (B-grade), and operation down to 100 µA cathode current. It delivers 0.25 Ω typical dynamic impedance and supports output voltage adjustment from 1.24 V to 18 V using two external resistors. It is used in isolated flyback SMPS secondary-side regulation and low-voltage Zener replacement applications.

For engineers reviewing the TLVH431IPKG3 datasheet, TLVH431IPKG3 pinout, TLVH431IPKG3 application, or TLVH431IPKG3 equivalent, key selection criteria include reference accuracy at 25°C, cathode current range (100 µA–70 mA), thermal stability over –40°C to +125°C, dynamic impedance, and SOT-89-3 package compatibility for high-power-density designs.

Technical Context

The TLVH431IPKG3 implements an internal 1.24 V bandgap reference and high-gain NPN-based error amplifier driving a Darlington sink output stage. Its open-loop configuration functions as a comparator with integrated reference; closed-loop operation enables precise shunt regulation via resistive feedback between cathode and reference pins.

It operates with no external compensation required and maintains stability across capacitive loads up to 10 nF when biased within recommended conditions. The device achieves sharp turn-on characteristics and low leakage (<0.1 µA off-state cathode current), enabling accurate voltage monitoring and low-power rail supervision.

Key Specifications

Pinout & Package

SOT-89-3 package (4.50 mm × 2.50 mm body) with gull-wing leads; thermally enhanced tab connected to anode for PCB heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431IPKG3, TLVH431ACPK trades 0.5% reference accuracy for lower unit cost in non-critical applications, while TLVH432IPK offers identical performance with inverted pin assignment-requiring layout change but enabling optimized trace routing in space-constrained designs.

Availability

TLVH431IPKG3 is available at Aetrix Electronics and suitable for isolated SMPS feedback, voltage rail monitoring, adjustable LDO reference, and Zener replacement applications requiring stable component supply across automotive, industrial, and telecom end equipment.

Supply support for TLVH431IPKG3 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 precision analog ICs and power management solutions.

The TLVH431 family was designed for high-accuracy, low-voltage shunt regulation in isolated and non-isolated power supplies, offering improved thermal stability and lower operating current than legacy TL431 devices.

FAQ

What is the reference voltage tolerance of TLVH431IPKG3 at 25°C?

The TLVH431IPKG3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to the 'B' grade suffix. This means its V_REF falls between 1.234 V and 1.246 V under nominal conditions, enabling high-precision feedback in critical power regulation circuits where TLVH431IPKG3 serves as the primary voltage reference.

Can TLVH431IPKG3 operate with cathode currents below 1 mA?

Yes - TLVH431IPKG3 is specifically designed for low-current operation, with a minimum cathode current of just 100 µA for regulation. This allows TLVH431IPKG3 to function reliably in ultra-low-power applications such as battery-backed monitors or energy-harvesting systems where traditional TL431 devices would fail to regulate.

What package type does TLVH431IPKG3 use, and how is it thermally optimized?

TLVH431IPKG3 uses the SOT-89-3 package (4.50 mm × 2.50 mm), with the ANODE pin internally connected to the exposed thermal tab. This design enables efficient heat transfer to the PCB copper pour, supporting continuous operation at up to 70 mA cathode current without external heatsinking - a key advantage of TLVH431IPKG3 in compact power designs.

How does TLVH431IPKG3 differ from TLVH432IPKG3 in pin configuration?

TLVH431IPKG3 uses Pin 1=CATHODE, Pin 2=REF, Pin 3=ANODE. TLVH432IPKG3 reverses REF and ANODE: Pin 1=REF, Pin 2=ANODE, Pin 3=CATHODE. Both share identical electrical specs, but TLVH431IPKG3's pinout aligns with legacy TL431 layouts, whereas TLVH432IPKG3 offers alternative routing flexibility - TLVH431IPKG3 must be selected when backward compatibility is required.

Is an output capacitor required for stability with TLVH431IPKG3?

No - TLVH431IPKG3 is internally compensated and remains stable without an output capacitor between cathode and anode. However, if a capacitor is added for noise filtering or transient suppression, TLVH431IPKG3 supports up to 10 nF while maintaining phase margin above 45°, as verified in TI's characterization data for the SOT-89 package variant.