Texas Instruments TLVH432BQDBZR

Overview

TLVH432BQDBZR from Texas Instruments is a B-grade (0.5% initial tolerance), 3-pin SOT-23 packaged, low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, 100 μA minimum cathode current, and –40°C to +125°C operating range. It functions as a programmable voltage reference or error amplifier in isolated flyback SMPS feedback loops, secondary-side regulation, and low-leakage Zener replacement circuits.

For engineers reviewing the TLVH432BQDBZR datasheet, TLVH432BQDBZR pinout, TLVH432BQDBZR application, or TLVH432BQDBZR equivalent, key selection criteria include reference voltage accuracy at temperature, dynamic impedance (0.25 Ω), cathode current range (100 μA–70 mA), thermal stability, and SOT-23-3 pin compatibility with TLVH431 variants.

Technical Context

The TLVH432BQDBZR implements a precision bandgap reference and high-gain transconductance amplifier in a 3-terminal shunt topology. Its internal architecture delivers sharp turn-on characteristics and stable regulation down to 1.24 V, enabling operation in 3.3 V and lower-input isolated power supplies where legacy TL431 devices cannot function.

Unlike the TLVH431, the TLVH432BQDBZR uses reversed pinout (REF–CATHODE–ANODE) in SOT-23-3 packaging-pin 1 = REF, pin 2 = CATHODE, pin 3 = ANODE-enabling direct integration into optocoupler-coupled feedback paths without PCB layout redesign when migrating from TLVH431-based designs requiring alternate routing.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: 2.92 mm × 1.30 mm body, gull-wing leads, JEDEC MO-178AC compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH432BQDBZR, TLVH431BQDBVR demands PCB redesign and offers no accuracy benefit, while TLVH432AQDBZR trades 0.5% tolerance for lower unit cost-making the B-grade optimal for high-stability feedback and precision monitoring where initial accuracy directly impacts system specification compliance.

Availability

TLVH432BQDBZR is available at Aetrix Electronics and suitable for isolated SMPS feedback, precision ADC references, and low-leakage voltage monitoring requiring stable component supply across automotive, industrial, and telecom production programs.

Supply support for TLVH432BQDBZR 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 signal chain technologies.

The TLVH432BQDBZR belongs to TI's precision shunt regulator product line, designed specifically for low-voltage, high-accuracy feedback in isolated power supplies, data acquisition systems, and voltage supervision circuits.

FAQ

What is the reference voltage tolerance of TLVH432BQDBZR at 25°C?

The TLVH432BQDBZR 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 specification is confirmed in Section 5.7 of the official datasheet and applies strictly to the TLVH432B variant in SOT-23-3 packaging. The TLVH432BQDBZR maintains this tolerance across its full –40°C to +125°C operating range with a maximum deviation of ±11 mV.

How does the pinout of TLVH432BQDBZR differ from TLVH431BQDBZR?

The TLVH432BQDBZR uses a REF–CATHODE–ANODE pinout (pin 1 = REF, pin 2 = CATHODE, pin 3 = ANODE) in its SOT-23-3 package, whereas TLVH431BQDBZR uses ANODE–REF–CATHODE (pin 1 = ANODE, pin 2 = REF, pin 3 = CATHODE). This reversal enables TLVH432BQDBZR to interface directly with optocoupler LEDs without trace rerouting in flyback feedback designs. Both share identical electrical behavior and B-grade tolerance, but TLVH432BQDBZR's pinout simplifies layout in secondary-side regulation topologies.

What is the minimum cathode current required for regulation in TLVH432BQDBZR?

The TLVH432BQDBZR requires a minimum cathode current (I_K(min)) of 100 μA to maintain regulation, as specified in Sections 5.5–5.7 of the datasheet. This value is guaranteed over the full –40°C to +125°C temperature range. Operating below this threshold risks loss of regulation accuracy and increased output impedance. Designers achieve this using feedback resistors sized to draw ≥100 μA at the lowest expected output voltage, ensuring stable closed-loop behavior in all operating conditions of TLVH432BQDBZR.

Can TLVH432BQDBZR be used as a comparator without external reference?

Yes, TLVH432BQDBZR can operate as a comparator with integrated reference in open-loop configuration. When biased with ≥100 μA cathode current and with the REF pin connected to a voltage divider, it compares that voltage to its internal 1.24 V reference and sharply switches the CATHODE current. This eliminates the need for external reference ICs in brown-out detectors or rail monitors. The TLVH432BQDBZR's high open-loop gain and fast turn-on make it suitable for such applications, as validated in Figure 8-2 and Section 7.4.1 of the datasheet.

What is the dynamic impedance of TLVH432BQDBZR and why does it matter?

The TLVH432BQDBZR has a typical dynamic impedance of 0.25 Ω, measured at 1 kHz with cathode current between 0.1 mA and 70 mA. This low value means the device exhibits minimal voltage change under varying load or feedback current-critical for maintaining tight regulation in SMPS feedback loops and precision reference applications. In practice, this enables <1 mV output variation for a 1 mA cathode current step, directly improving system accuracy and transient response in TLVH432BQDBZR-based designs.