Texas Instruments TLVH431ILPE3

Overview

TLVH431ILPE3 from Texas Instruments is a low-voltage adjustable precision shunt regulator in TO-92 package, providing 1.24 V reference voltage with ±0.5% initial tolerance (B-grade), 100 μA minimum cathode current for regulation, and operation from –40°C to +125°C. It functions as a programmable Zener replacement or error amplifier in isolated flyback SMPS feedback loops.

For engineers reviewing the TLVH431ILPE3 datasheet, TLVH431ILPE3 pinout, TLVH431ILPE3 application, or TLVH431ILPE3 equivalent, key selection criteria include its 1.24 V low-voltage reference, ultra-low 0.1–0.5 μA reference terminal current, 0.25 Ω dynamic impedance, and compatibility with optocoupler-based secondary-side regulation in 3.3 V systems.

Technical Context

The TLVH431ILPE3 implements a three-terminal shunt-regulator architecture with an internal 1.24 V bandgap reference and high-gain NPN-based error amplifier driving a Darlington output stage. Its open-loop mode enables comparator functionality with integrated reference, while closed-loop operation-via resistive feedback between cathode and reference pins-enables precise voltage regulation from VREF to 18 V.

It operates without external compensation, featuring internal frequency compensation that ensures stability across capacitive loads up to 10 nF. The device maintains sharp turn-on characteristics and low leakage (≤0.1 μA off-state cathode current), making it suitable for low-power monitoring and regulation where thermal drift and supply headroom are constrained.

Key Specifications

Pinout & Package

TLVH431ILPE3 uses a 3-pin TO-92 package (body size 4.30 mm × 4.30 mm) with through-hole mounting. 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 TLVH431ILPE3, TLVH431CLPE3 trades accuracy and temperature range for lower cost, while TLVH432ILP offers identical performance in a thermally superior surface-mount package-neither is pin-compatible due to differing footprints and pin assignments.

Availability

TLVH431ILPE3 is available at Aetrix Electronics and suitable for automotive power management, industrial sensor interfaces, and isolated DC/DC converter designs requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for TLVH431ILPE3 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, delivering analog and embedded processing solutions for industrial, automotive, and communications markets since 1930.

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

FAQ

What is the reference voltage tolerance of TLVH431ILPE3 at 25°C?

The TLVH431ILPE3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal VREF with a range of 1.234 V to 1.246 V. This B-grade specification is confirmed in Section 5.7 of the TI SLVS555N datasheet and applies across the full operating temperature range of –40°C to +125°C.

Can TLVH431ILPE3 be used in place of a Zener diode?

Yes, TLVH431ILPE3 serves as a high-accuracy, low-leakage Zener diode replacement. With 0.1–0.5 μA reference current and 0.1 μA off-state cathode current, it delivers significantly lower leakage than standard Zeners. Its adjustable output (1.24 V to 18 V) and sharp turn-on characteristic make TLVH431ILPE3 ideal for precision clamping and regulation where Zener voltage drift and temperature coefficient are critical.

What is the minimum cathode current required for regulation with TLVH431ILPE3?

The TLVH431ILPE3 requires a minimum cathode current of 100 μA to maintain regulation, as specified in the "IK(min)" parameter under Electrical Characteristics. This value holds across the full –40°C to +125°C temperature range and is validated in Figure 5-5 (Minimum Cathode Current vs. Temperature). Below this threshold, gain drops and regulation becomes unstable.

Does TLVH431ILPE3 require an external output capacitor for stability?

No, TLVH431ILPE3 is internally compensated and remains stable without an external output capacitor between cathode and anode. However, if a capacitor is added for noise filtering or transient response shaping, Figures 5-15 to 5-17 in the datasheet provide phase-margin guidance for capacitive loads up to 10 nF. Stability is maintained across all recommended operating conditions without mandatory external capacitance.

How does the TO-92 package of TLVH431ILPE3 affect thermal performance?

The TO-92 package of TLVH431ILPE3 has a junction-to-ambient thermal resistance (RθJA) of 140°C/W, per TI's SLVS555N datasheet. This limits continuous power dissipation to approximately 357 mW at 25°C ambient. For higher-power applications, derating is required-e.g., 214 mW at 70°C ambient. The package supports through-hole assembly and offers mechanical robustness but lower thermal efficiency than SOT-89 or SC70 alternatives.