Texas Instruments TLVH431BQDBZRG4

Overview

TLVH431BQDBZRG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-23-3 package, delivering 1.24 V reference voltage with ±0.5% initial tolerance at 25°C, 100 μA minimum cathode current for regulation, 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 TLVH431BQDBZRG4 datasheet, TLVH431BQDBZRG4 pinout, TLVH431BQDBZRG4 application, or TLVH431BQDBZRG4 equivalent, key selection criteria include reference accuracy over temperature, cathode current range (100 μA–70 mA), dynamic impedance (0.25 Ω), and compatibility with optocoupler-based secondary-side regulation in 3.3 V systems.

Technical Context

The TLVH431BQDBZRG4 implements a bandgap-referenced error amplifier with Darlington output stage, enabling precise shunt regulation down to 1.24 V - lower than TL431's 2.5 V reference. Its internal architecture supports both open-loop comparator operation (with integrated 1.24 V threshold) and closed-loop shunt regulation via external resistor divider feedback between cathode and reference pins.

It operates with no external compensation required, featuring inherent stability across capacitive loads up to 10 nF when configured as a shunt regulator. The device maintains specified performance across industrial and automotive temperature ranges (–40°C to +125°C), with typical output impedance of 0.25 Ω and reference voltage drift of ≤31 mV over full temperature range for the Q-grade variant.

Key Specifications

Pinout & Package

SOT-23-3 package (2.92 mm × 1.30 mm body size), surface-mount, RoHS-compliant, with 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 TLVH431BQDBZRG4, TLVH431BIDBZR sacrifices automotive temperature capability for lower cost, while TLVH432BQDBZR retains identical performance but mandates board-level changes due to non-interchangeable pinout - neither is a drop-in replacement without validation.

Availability

TLVH431BQDBZRG4 is available at Aetrix Electronics and suitable for isolated power supplies, automotive body electronics, and industrial sensor interfaces requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for TLVH431BQDBZRG4 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, high-accuracy shunt regulation in isolated power conversion and system supervision - targeting automotive, industrial, and telecom applications demanding robustness across extreme temperatures.

FAQ

What is the reference voltage tolerance of TLVH431BQDBZRG4 at 25°C?

The TLVH431BQDBZRG4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal value with min/max bounds of 1.234 V and 1.246 V. This grade-B tolerance is confirmed in Section 5.7 of the TI datasheet SLVS555N and applies specifically to the Q-grade (–40°C to +125°C) variant. TLVH431BQDBZRG4 maintains tighter initial accuracy than A-grade (±1%) or standard-grade (±1.5%) versions.

Can TLVH431BQDBZRG4 operate with cathode current below 100 μA?

No - TLVH431BQDBZRG4 requires ≥100 μA cathode current to enter and sustain regulation mode, as specified in its IK(min) parameter. Below this threshold, the internal amplifier exits linear operation, causing loss of reference accuracy and increased output impedance. While the device may exhibit comparator-like behavior at lower currents, TLVH431BQDBZRG4 is not characterized or guaranteed for regulation below 100 μA, even at room temperature.

What is the maximum output voltage adjustable with TLVH431BQDBZRG4?

The TLVH431BQDBZRG4 supports adjustable output voltages up to 18 V, achieved by configuring external resistors R1 and R2 per the formula V_OUT = V_REF × (1 + R1/R2) + I_ref × R1. This upper limit is defined in the Recommended Operating Conditions table (Section 5.3) and validated across the full –40°C to +125°C range. Exceeding 18 V cathode-to-anode voltage risks violating absolute maximum ratings and may cause permanent damage to TLVH431BQDBZRG4.

Does TLVH431BQDBZRG4 require an output capacitor for stability?

No - TLVH431BQDBZRG4 is internally compensated and stable without an output capacitor between cathode and anode, unlike many linear regulators. This is explicitly stated in Section 7.3 of the datasheet. However, if a capacitor is added for noise filtering or transient response shaping, Figures 5-15 through 5-17 provide phase-margin guidance for selecting values up to 10 nF depending on cathode voltage and load conditions.

How does TLVH431BQDBZRG4 differ from TLVH432BQDBZR in pin configuration?

TLVH431BQDBZRG4 uses pin 1 = CATHODE, pin 2 = ANODE, pin 3 = REF in SOT-23-3. TLVH432BQDBZR swaps ANODE and REF: pin 1 = REF, pin 2 = ANODE, pin 3 = CATHODE. This reversal makes them electrically identical but mechanically incompatible - direct substitution requires PCB trace modification. The TLVH431BQDBZRG4 pinout matches standard TL431-derived layouts, while TLVH432BQDBZR aligns with alternate feedback topologies.