Texas Instruments TLVH431QDBVR

Overview

TLVH431QDBVR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±0.5% initial tolerance at 25°C (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 - ideal for secondary-side regulation in isolated 3.3 V flyback SMPSs.

For engineers reviewing the TLVH431QDBVR datasheet, TLVH431QDBVR pinout, TLVH431QDBVR application, or TLVH431QDBVR equivalent, key selection criteria include its Q-grade (–40°C to +125°C) thermal stability, ultra-low reference leakage (<0.5 µA), SC-70 package footprint, and compatibility with optocoupler-based feedback loops requiring sharp turn-on and stable error amplification.

Technical Context

The TLVH431QDBVR implements an internal bandgap reference and high-gain NPN-based error amplifier driving a Darlington sink output stage. Its functional block includes a precision 1.24 V reference, differential input comparator, and active current sink capable of regulating cathode voltage across 1.24 V–18 V with <31 mV total VREF deviation over –40°C to +125°C.

It operates in two distinct modes: open-loop comparator mode (reference pin compared to external signal) and closed-loop shunt regulator mode (feedback from cathode to reference). Stability is internally compensated - no output capacitor required - though phase margin vs. capacitive load is characterized up to 100 nF for design validation.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 5-pin surface-mount with exposed substrate connection (Pin 2).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431BDBVR, TLVH431QDBVR trades 0.5% initial tolerance for broader production yield and lower cost, while maintaining identical –40°C to +125°C performance and SC-70-compatible footprint. Against TLVH432QDBVR, it provides superior thermal anchoring via Pin 2 substrate tie and avoids pinout rework in existing DBV-based designs.

Availability

TLVH431QDBVR is available at Aetrix Electronics and suitable for automotive power management, industrial SMPS feedback, and precision analog reference applications requiring stable component supply across extended temperature ranges.

Supply support for TLVH431QDBVR 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 ICs, with decades of expertise in precision reference and power control technologies.

The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in space-constrained and thermally demanding applications - extending the TL431 architecture to 1.24 V operation while enhancing thermal stability and leakage performance.

FAQ

What is the reference voltage tolerance of TLVH431QDBVR at 25°C?

The TLVH431QDBVR has a ±0.5% reference voltage tolerance at 25°C, corresponding to the 'B' grade suffix. Its nominal VREF is 1.24 V, yielding a 1.234 V to 1.246 V range at room temperature. This tolerance is maintained across the full –40°C to +125°C operating range with ≤31 mV total deviation, making TLVH431QDBVR suitable for high-accuracy automotive and industrial feedback circuits.

Can TLVH431QDBVR replace TL431 in existing designs?

TLVH431QDBVR can replace TL431 in many designs but requires verification of cathode headroom and biasing. Unlike TL431 (2.5 V VREF), TLVH431QDBVR operates down to 1.24 V, enabling use in lower-voltage systems. However, its SOT-23-5 DBV package differs from TL431's TO-92 or SOIC-8, and minimum cathode current is 100 µA (vs. 1 mA for TL431), so resistor values and stability margins must be re-evaluated. TLVH431QDBVR is not pin-compatible with TL431.

What is the purpose of Pin 2 (substrate) on TLVH431QDBVR?

Pin 2 on TLVH431QDBVR is the die substrate connection and must be connected to the ANODE terminal or left electrically open - it is not a signal pin. This connection improves thermal dissipation and ESD robustness. Leaving Pin 2 unconnected or floating may degrade long-term reliability and increase susceptibility to latch-up under transient conditions. TI explicitly states this requirement in the pin function table and mechanical drawings.

Does TLVH431QDBVR require an output capacitor for stability?

No, TLVH431QDBVR is internally compensated and does not require an output capacitor between CATHODE and ANODE for basic stability. Its architecture ensures phase margin >45° across 0–100 nF capacitive loads at 1.25 V, 2.5 V, and 5 V cathode voltages, as verified in Figures 5-15 through 5-17 of the datasheet. However, if added for noise filtering, capacitor value must be selected using those curves to avoid instability.

How does TLVH431QDBVR function as a comparator?

In open-loop comparator mode, TLVH431QDBVR compares voltage at the REF pin to its internal 1.24 V reference. When REF voltage exceeds 1.24 V, the cathode sinks current; when below, it remains off. With ≥100 µA cathode current supplied externally, TLVH431QDBVR delivers sharp turn-on behavior and >60 dB open-loop gain - enabling precise threshold detection without external op-amps. The REF pin must never be left floating, as it draws 0.1–0.5 µA bias current.