Texas Instruments TL432LIAQDBZR

Overview

TL432LIAQDBZR from Texas Instruments is a three-terminal programmable shunt regulator with 1% initial reference voltage tolerance at 25°C, 2.495 V nominal reference voltage, adjustable output from 2.495 V to 36 V, 0.3 Ω typical dynamic impedance, and −40°C to +125°C operating range. It serves as a precision voltage reference and error amplifier in secondary-side regulation of isolated flyback converters.

For engineers reviewing the TL432LIAQDBZR datasheet, TL432LIAQDBZR pinout, TL432LIAQDBZR application, or TL432LIAQDBZR equivalent, key selection criteria include reference accuracy (1%), temperature drift (27 mV over −40°C to +125°C), cathode current capability (1–15 mA), reference input current (≤0.4 µA), and SOT-23 (DBZ) package compatibility with space-constrained industrial power designs.

Technical Context

The TL432LIAQDBZR implements an internal bandgap reference and high-gain op-amp driving a Darlington sink output stage, enabling precise shunt regulation via external resistive feedback between cathode and reference pins. Its open-loop comparator mode supports voltage monitoring with integrated reference.

Unlike standard linear regulators, it requires no external compensation capacitor for stability and operates with only 1 mA minimum cathode current. The DBZ package pinout (CATHODE–REF–ANODE) differs from TL431LI but delivers identical electrical performance and thermal specs (R_θJA = 371.7°C/W).

Key Specifications

Pinout & Package

TL432LIAQDBZR uses the 3-pin SOT-23 (DBZ) package, measuring 2.90 mm × 1.30 mm, with gull-wing leads optimized for automated assembly and thermal dissipation in compact PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL432LIAQDBZR, TL431LIAQDBZR demands board-level pinout adaptation but offers identical performance, while TL432LIBQDBZR delivers higher accuracy at the expense of tighter initial tolerance specification-making it suitable for metrology-grade current sinks or ultra-stable references where 0.5% matters.

Availability

TL432LIAQDBZR is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and isolated DC-DC converters requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.

Supply support for TL432LIAQDBZR 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 for industrial, automotive, and communications markets.

The TL43xLI family was designed specifically for precision shunt regulation and reference applications in safety-critical and thermally demanding environments, emphasizing low drift, high accuracy, and robust operation across extended temperature ranges.

FAQ

What is the reference voltage tolerance of TL432LIAQDBZR at 25°C?

The TL432LIAQDBZR has a reference voltage tolerance of ±1% at 25°C, corresponding to a nominal 2.495 V output with a range of 2.470 V to 2.520 V. This A-grade accuracy is specified in the Electrical Characteristics table of the SLVSDQ6A datasheet and applies across the full Q-temp operating range when combined with its 27 mV total temperature drift.

How does the TL432LIAQDBZR pinout differ from TL431LI in the DBZ package?

The TL432LIAQDBZR uses a CATHODE–REF–ANODE pinout (Pin 1 = REF, Pin 2 = CATHODE, Pin 3 = ANODE), whereas TL431LIAQDBZR uses CATHODE–ANODE–REF (Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF). This difference is explicitly documented in the Pin Configuration section of the SLVSDQ6A datasheet and requires PCB layout adjustment when substituting between the two.

Can TL432LIAQDBZR operate without an output capacitor?

Yes, TL432LIAQDBZR is internally compensated and stable without an output capacitor between cathode and anode. The datasheet confirms this in Section 9.3 and Figure 12, which shows stability boundaries assuming no external capacitor. However, if added, the capacitor value must be selected per the stability chart to avoid oscillation-especially critical in high-noise automotive environments.

What is the minimum cathode current required for regulation in TL432LIAQDBZR?

The TL432LIAQDBZR requires a minimum cathode current (I_KA) of 1 mA to maintain regulation, as specified in Section 7.4 (Recommended Operating Conditions) and Table 7.5 (Electrical Characteristics). Below this threshold, open-loop gain drops significantly, causing slow response and potential loss of regulation-particularly relevant in low-power standby modes of flyback converters.

Is TL432LIAQDBZR qualified for automotive applications?

Yes, TL432LIAQDBZR is qualified for automotive use as a Q-temp device, rated for operation from −40°C to +125°C and meeting AEC-Q100 stress testing requirements. Its 27 mV total reference voltage drift over this range and robust ESD ratings (±2000 V HBM) make it suitable for under-hood power management, body control modules, and infotainment power rails.