Texas Instruments TLVH431IDBVT

Overview

TLVH431IDBVT from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±1% initial tolerance at 25°C (I-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 - ideal for secondary-side regulation in isolated 3.3 V flyback SMPS designs.

For engineers reviewing the TLVH431IDBVT datasheet, TLVH431IDBVT pinout, TLVH431IDBVT application, or TLVH431IDBVT equivalent, this device serves as a low-leakage, thermally stable replacement for Zener diodes and enables precise voltage monitoring, error amplification, and comparator functions in space-constrained industrial and telecom power systems.

Technical Context

The TLVH431IDBVT integrates an internal 1.24 V bandgap reference and high-gain transconductance amplifier driving a Darlington output stage. Its open-loop configuration functions as a comparator with integrated reference; closed-loop operation with cathode-to-reference feedback realizes adjustable shunt regulation.

It operates across –40°C to +85°C (I-grade), maintains <12 mV VREF deviation over full temperature range, and achieves stable regulation without external compensation - unlike many linear regulators - due to internal frequency compensation optimized for cathode-anode capacitive loads up to 10 nF.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: 2.92 mm × 1.30 mm body, 3-pin surface-mount with gull-wing leads. Thermal resistance R_θJA = 206 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ACDBZR, TLVH431IDBVT provides guaranteed operation to –40°C and +85°C, critical for outdoor or factory-floor deployments; compared with TLVH432IDBVT, it retains legacy pin compatibility for drop-in replacement in established designs without layout change.

Availability

TLVH431IDBVT is available at Aetrix Electronics and suitable for industrial power supplies, telecom DC/DC modules, and embedded sensor signal chains requiring stable component supply with full I-grade temperature qualification.

Supply support for TLVH431IDBVT 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 design.

The TLVH431 family was engineered to extend shunt regulator functionality to low-voltage systems - replacing Zeners and enabling accurate feedback in 3.3 V and lower isolated power architectures.

FAQ

What is the minimum cathode current required for regulation in TLVH431IDBVT?

The TLVH431IDBVT requires a minimum cathode current of 100 µA to maintain regulation across its full operating temperature range (–40°C to +85°C). At 25°C, regulation begins at 60 µA, but design margins require 100 µA to ensure stability under worst-case conditions. This value is specified in Section 5.5 of the TI SLVS555N datasheet and verified per Figure 5-5's Ik(min) vs. temperature curve. TLVH431IDBVT must receive ≥100 µA continuously at the CATHODE pin to sustain accurate 1.24 V reference behavior.

How does TLVH431IDBVT differ from TL431 in practical circuit design?

TLVH431IDBVT operates down to 1.24 V cathode-anode voltage and draws only 100 µA minimum cathode current, whereas TL431 requires ≥2.5 V and ≥1 mA. This allows TLVH431IDBVT to regulate 1.8 V and 3.3 V rails directly and reduces standby power by >90%. Its lower reference voltage also enables tighter feedback thresholds in low-voltage comparators. TLVH431IDBVT is pin-compatible with TL431 in SOT-23-3 but not electrically interchangeable due to differing headroom and current requirements.

Can TLVH431IDBVT be used without an output capacitor?

Yes - TLVH431IDBVT is internally compensated and remains stable without a cathode-to-anode output capacitor, unlike many shunt regulators that require external capacitance for phase margin. This simplifies layout and improves reliability in space-constrained designs. However, if a capacitor is added for noise filtering, Figures 5-15 through 5-17 in the SLVS555N datasheet provide stability guidance for loads up to 10 nF depending on cathode voltage.

What is the role of the REF pin in TLVH431IDBVT, and what happens if left floating?

The REF pin is a high-impedance input that senses external voltage against the internal 1.24 V reference. It must never be left floating: the internal NPN input stage requires 0.1–0.5 µA base current (I_REF) to operate correctly. An unconnected REF pin causes unpredictable turn-on behavior, regulation failure, or oscillation. Always tie REF to a defined voltage via a resistor divider or direct connection - even in comparator mode, a pull-down or pull-up is mandatory for deterministic operation.

Is TLVH431IDBVT suitable for automotive applications?

TLVH431IDBVT is rated for –40°C to +85°C (I-grade), meeting standard industrial temperature requirements but not AEC-Q100 automotive qualification. For automotive use, TI offers the Q-grade variant TLVH431QDBVR (–40°C to +125°C) with enhanced reliability testing. TLVH431IDBVT may be deployed in non-safety-critical cabin electronics with controlled thermal environments, but Aetrix Electronics recommends TLVH431QDBVR for under-hood or ADAS-related designs requiring full automotive qualification.