Texas Instruments TLVH431ILP

Overview

TLVH431ILP from Texas Instruments is a low-voltage adjustable precision shunt regulator in TO-92 package, providing 1.24 V reference voltage with ±1.5% initial tolerance at 25°C, 100 μA to 70 mA cathode current range, and operation from –40°C to +125°C. It functions as an integrated voltage reference and error amplifier in isolated flyback SMPS feedback loops.

For engineers reviewing the TLVH431ILP datasheet, TLVH431ILP pinout, TLVH431ILP application, or TLVH431ILP equivalent, key selection criteria include reference accuracy grade (standard/1.5%), thermal stability over industrial temperature range, cathode current headroom for regulation, and compatibility with optocoupler-based secondary-side control architectures.

Technical Context

The TLVH431ILP implements a precision bandgap reference (1.24 V) combined with a high-gain NPN-based error amplifier and Darlington output stage. Its internal architecture enables stable closed-loop regulation when configured with external resistive dividers, or open-loop comparator operation with integrated reference.

It operates down to 1.24 V cathode-to-anode voltage, requires ≥100 μA minimum cathode current for regulation, and delivers 0.25 Ω typical dynamic impedance. The device is internally compensated and does not require an output capacitor for stability in standard configurations.

Key Specifications

Pinout & Package

TLVH431ILP uses a 3-pin TO-92 package (4.30 mm × 4.30 mm body), with leads designated Cathode, Anode, and Reference. The Anode serves as the common return node; the Reference pin senses the regulated voltage point; the Cathode sinks current to maintain regulation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ILP, TLVH431ACLP offers improved initial accuracy without changing layout or thermal design, while TLVH431BCLP provides the highest precision option in the same TO-92 footprint-both retain identical electrical behavior, pinout, and thermal characteristics.

Availability

TLVH431ILP is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and embedded sensor systems requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for TLVH431ILP 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in isolated power supplies and precision monitoring applications-addressing limitations of legacy TL431 in sub-2.5 V systems.

FAQ

What is the reference voltage tolerance of TLVH431ILP at 25°C?

The TLVH431ILP has a standard-grade reference voltage tolerance of ±1.5% at 25°C, corresponding to a 1.24 V nominal V_REF with a range of 1.222 V to 1.258 V. This is confirmed in Section 5.5 of the TI SLVS555N datasheet for the TLVH431x grade. The 'I' suffix denotes –40°C to +85°C operation, and 'LP' specifies the TO-92 package - both fully compatible with the 1.5% tolerance bin.

Does TLVH431ILP require an output capacitor for stability?

No, TLVH431ILP is internally compensated and does not require an output capacitor between Cathode and Anode for basic stability in standard shunt regulator configurations. As stated in Section 7.3, its architecture avoids the need for external compensation. 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 for selecting appropriate values.

What is the minimum cathode current needed for regulation in TLVH431ILP?

The TLVH431ILP requires a minimum cathode current of 100 μA to enter and maintain regulation, as specified in Section 5.5 (IK(min)) of the datasheet. This value is valid across the full operating temperature range. Below this threshold, the device may exhibit reduced gain and unstable regulation - critical when designing with high-impedance optocouplers or low-power bias networks.

How does TLVH431ILP differ from TL431 in practical design?

TLVH431ILP operates down to 1.24 V (vs. TL431's 2.5 V), draws only 0.1–0.5 μA reference current (vs. ~4 μA for TL431), and starts regulation at 100 μA cathode current (vs. 1 mA for TL431). These differences enable TLVH431ILP to regulate lower voltages, reduce divider power loss, and interface directly with low-current optocouplers - making it the preferred choice for 3.3 V and below isolated SMPS designs.

Can TLVH431ILP be used as a comparator?

Yes, TLVH431ILP functions as a comparator with integrated 1.24 V reference in open-loop mode. When cathode current ≥100 μA is supplied and no feedback is applied to the REF pin, the device exhibits high open-loop gain and sharp turn-on, as shown in Figure 5-4. This configuration is explicitly supported in Section 7.4.1 and Application Figure 8-2 for voltage monitoring and reset generation tasks.