Texas Instruments TLVH431ACLP

Overview

TLVH431ACLP from Texas Instruments is a low-voltage adjustable precision shunt regulator in TO-92 package, functioning as a 1.24 V reference with ±1% initial tolerance at 25°C, 100 μA minimum cathode current for regulation, 0.25 Ω typical dynamic impedance, and operation across –40°C to +125°C. It replaces Zener diodes in secondary-side regulation of isolated 3.3 V flyback SMPSs.

For engineers reviewing the TLVH431ACLP datasheet, TLVH431ACLP pinout, TLVH431ACLP application, or TLVH431ACLP equivalent, key selection criteria include reference voltage accuracy over temperature, cathode current range (100 μA–70 mA), dynamic impedance stability, thermal performance in TO-92, and compatibility with optocoupler-based feedback loops.

Technical Context

The TLVH431ACLP implements a bandgap-referenced error amplifier with internal 1.24 V reference and Darlington output stage, enabling precise shunt regulation via external resistor divider between cathode and reference pins. Its open-loop gain supports comparator operation with integrated reference, while closed-loop configuration delivers stable voltage regulation down to 1.24 V.

It operates with cathode-to-anode voltage from 1.24 V to 18 V and maintains specified performance across industrial and automotive temperature ranges. The TO-92 package provides 140 °C/W junction-to-ambient thermal resistance, supporting continuous 70 mA cathode current with appropriate PCB copper area.

Key Specifications

Pinout & Package

TLVH431ACLP uses a 3-pin TO-92 package (4.30 mm × 4.30 mm body) with through-hole mounting and standard lead spacing. Pin 1 is CATHODE, Pin 2 is ANODE, and Pin 3 is REF - no NC or substrate pins present in this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431BCLP and TLVH431ACLPG3, the TLVH431ACLP offers optimal cost-performance balance for industrial and commercial power management, delivering verified 1% reference accuracy and full –40°C to +125°C operation without automotive qualification overhead or premium tolerance pricing.

Availability

TLVH431ACLP is available at Aetrix Electronics and suitable for industrial power supplies, telecom voltage supervisors, and embedded analog front-ends requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TLVH431ACLP 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, embedded processing, and power management technologies, with decades of expertise in precision reference and power control ICs.

The TLVH431 family was designed specifically for low-voltage shunt regulation in isolated and non-isolated power converters, offering improved accuracy, lower operating voltage, and wider temperature range than legacy TL431 devices.

FAQ

What is the reference voltage tolerance of TLVH431ACLP at 25°C?

The TLVH431ACLP has a reference voltage tolerance of ±1% at 25°C, meaning its V_REF falls within 1.228 V to 1.252 V under nominal conditions. This tolerance is guaranteed per TI's SLVS555N datasheet Section 5.6, and applies specifically to the 'A' grade variant in TO-92 packaging. The TLVH431ACLP maintains this specification across its full operating temperature range when used within recommended cathode current limits.

Can TLVH431ACLP regulate output voltages below 3.3 V?

Yes, TLVH431ACLP can regulate output voltages as low as 1.24 V - its internal reference voltage - by configuring the external resistor divider appropriately. In isolated flyback topologies with optocouplers, it enables regulated outputs down to ~2.7 V (1.24 V + typical optocoupler LED forward voltage). The TLVH431ACLP achieves this with only 100 μA minimum cathode current, making it viable for ultra-low-voltage, low-power applications where TL431 fails.

What is the maximum cathode-to-anode voltage for TLVH431ACLP?

The absolute maximum cathode-to-anode voltage for TLVH431ACLP is 20 V, but the recommended operating range is 1.24 V to 18 V. Operating above 18 V risks exceeding power dissipation limits in the TO-92 package, especially at elevated temperatures. At 18 V and 70 mA cathode current, power dissipation reaches 1.26 W - requiring significant PCB copper area to maintain junction temperature below 150°C.

Does TLVH431ACLP require an output capacitor for stability?

No, TLVH431ACLP is internally compensated and remains stable without an output capacitor between cathode and anode. This eliminates capacitor-related aging, ESR drift, and board space concerns in critical feedback paths. However, if a capacitor is added for noise filtering or transient suppression, Figures 5-15 to 5-17 in the TI datasheet provide phase-margin guidance for capacitive loads up to 10 nF depending on cathode voltage.

How does TLVH431ACLP differ from TLVH432 variants?

TLVH431ACLP and TLVH432 share identical electrical specifications but differ in pinout: TLVH431ACLP uses CATHODE–ANODE–REF (Pin 1–2–3), while TLVH432 variants reverse REF and ANODE. This makes them non-interchangeable without PCB layout changes. The TLVH431ACLP's TO-92 pinout matches legacy TL431 mechanical footprints, easing drop-in replacement in existing designs where pin compatibility is essential.