Texas Instruments TLVH431BQDBZR

Overview

TLVH431BQDBZR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 0.5% initial reference voltage tolerance at 25°C, 1.24 V nominal reference voltage, and operation down to 1.24 V cathode-anode voltage. It delivers stable regulation across –40°C to +125°C, supports cathode current from 100 μA to 70 mA, and features 0.25 Ω typical dynamic impedance - enabling use as a Zener replacement or error amplifier in isolated flyback SMPS feedback loops.

For engineers reviewing the TLVH431BQDBZR datasheet, TLVH431BQDBZR pinout, TLVH431BQDBZR application, or TLVH431BQDBZR equivalent, key selection considerations include its B-grade accuracy, SOT-23-3 (DBZ) package pin compatibility with TLVH432 variants, thermal stability over automotive temperature range, and suitability for secondary-side regulation in 3.3 V and lower isolated power supplies.

Technical Context

The TLVH431BQDBZR implements a precision bandgap reference and high-gain transconductance amplifier in a 3-terminal shunt topology. Its internal architecture forces the REF pin to 1.24 V relative to ANODE when sufficient cathode current (≥100 μA) flows and feedback is applied, enabling adjustable output voltage from 1.24 V to 18 V via two external resistors.

Unlike the TL431, it operates at lower headroom (down to 1.24 V), draws sub-0.5 μA reference input current, and achieves sharp turn-on with active output circuitry. It is internally compensated for stability without an output capacitor but supports capacitive loading up to 10 nF depending on cathode voltage.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: 2.92 mm × 1.30 mm body, gull-wing leads, surface-mount compatible, rated for 206°C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AQDBZR, TLVH431BQDBZR provides tighter initial accuracy for precision regulation; compared with TLVH432BQDBZR, it retains standard pinout compatibility with legacy TL431-based designs and simplifies layout reuse.

Availability

TLVH431BQDBZR is available at Aetrix Electronics and suitable for automotive power management, industrial sensor signal conditioning, and isolated DC/DC converter design requiring stable component supply across extended temperature ranges.

Supply support for TLVH431BQDBZR 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 delivering analog and embedded processing solutions, with leadership in precision analog, power management, and interface technologies.

The TLVH431 family was designed for low-voltage, high-accuracy shunt regulation in space-constrained and thermally demanding applications - especially secondary-side feedback in isolated switching power supplies and precision voltage monitoring.

FAQ

What is the reference voltage tolerance of TLVH431BQDBZR at 25°C?

The TLVH431BQDBZR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal V_REF with a range of 1.234 V to 1.246 V. This B-grade accuracy is specified in Section 5.7 of the TI datasheet and applies across the SOT-23-3 (DBZ) packaged device. The TLVH431BQDBZR maintains this tolerance over its full operating temperature range of –40°C to +125°C with defined deviation limits.

Can TLVH431BQDBZR operate with cathode voltage below 2.5 V?

Yes, TLVH431BQDBZR is specifically designed for low-voltage operation and functions with cathode-to-anode voltage (V_KA) as low as 1.24 V - its internal reference voltage. This enables direct regulation from 1.8 V or 2.5 V supply rails without additional headroom, unlike the TL431 which requires ≥2.5 V. The device remains in regulation with cathode current ≥100 μA across this range, per Section 5.3 Recommended Operating Conditions.

What is the maximum capacitive load TLVH431BQDBZR can drive stably?

TLVH431BQDBZR is internally compensated and does not require an output capacitor for basic stability. However, when driving capacitive loads, stability depends on cathode voltage and load value: Figure 5-15 shows phase margin remains >45° up to ~10 nF at V_KA = 1.25 V, but drops below 45° above ~3 nF at V_KA = 5 V. For robust design, TI recommends limiting capacitive load to ≤1 nF unless compensated per SLUA671 guidelines.

How does TLVH431BQDBZR differ from TLVH432BQDBZR?

TLVH431BQDBZR and TLVH432BQDBZR share identical electrical specifications, accuracy, and thermal rating, but differ in pinout: TLVH431BQDBZR uses Pin 1=CATHODE, Pin 2=REF, Pin 3=ANODE; TLVH432BQDBZR uses Pin 1=CATHODE, Pin 2=ANODE, Pin 3=REF. This swap affects PCB layout and schematic connectivity - TLVH431BQDBZR matches standard TL431 pinout, while TLVH432BQDBZR offers alternative routing flexibility in dense designs.

Is TLVH431BQDBZR suitable for use as a comparator?

Yes, TLVH431BQDBZR operates effectively as a comparator with integrated reference in open-loop configuration. When cathode current ≥100 μA is supplied and no feedback is applied to REF, the device exhibits high open-loop gain and sharp turn-on, allowing precise voltage threshold detection. The REF pin serves as the input, and CATHODE acts as the output - enabling rail-to-rail monitoring of power rails or sensor signals without external components.