Texas Instruments TLVH432CPKG3

Overview

TLVH432CPKG3 from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-89-3 package, providing 1.24 V reference voltage with ±1% initial tolerance (A grade), 0.25 Ω typical dynamic impedance, and operation from 1.24 V to 18 V output range. It serves as an error amplifier or voltage reference in isolated flyback SMPS feedback loops, replacing Zener diodes with lower leakage and sharper turn-on.

For engineers reviewing the TLVH432CPKG3 datasheet, TLVH432CPKG3 pinout, TLVH432CPKG3 application, or TLVH432CPKG3 equivalent, key selection criteria include cathode current range (100 μA–70 mA), thermal stability over –40°C to +125°C, SOT-89 pin configuration, and compatibility with optocoupler-based secondary-side regulation in 3.3 V power supplies.

Technical Context

The TLVH432CPKG3 implements a three-terminal shunt topology with internal 1.24 V bandgap reference and high-gain transconductance amplifier driving a Darlington sink output stage. Its functional block includes a precision reference input (REF), cathode current sink (CATHODE), and common return path (ANODE), enabling closed-loop regulation via resistive divider feedback or open-loop comparator operation.

Unlike the TLVH431, the TLVH432 variant uses reversed pinout in SOT-89: Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE - confirmed for PK package variants. This pin assignment supports direct integration into compact, thermally constrained secondary-side PCB layouts without requiring trace rerouting when migrating from legacy TL431-based designs.

Key Specifications

Pinout & Package

SOT-89-3 package (4.50 mm × 2.50 mm body) with gull-wing leads, optimized for thermal dissipation in power regulation applications. Mold compound meets JEDEC moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH432CPKG3, TLVH432ACPKG3 offers higher initial accuracy at no change in thermal performance, while TLVH432IPKG3 trades junction temperature capability for lower unit cost - both retain identical SOT-89 pinout and dynamic impedance, enabling drop-in replacement within their respective grade boundaries.

Availability

TLVH432CPKG3 is available at Aetrix Electronics and suitable for isolated flyback SMPS feedback, precision voltage monitoring, Zener replacement, and comparator-based supervision requiring stable component supply across automotive, industrial, and telecom power designs.

Supply support for TLVH432CPKG3 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 TLVH43x family was designed specifically to extend shunt regulator functionality to low-voltage systems (down to 1.24 V), targeting secondary-side regulation in energy-efficient 3.3 V and 5 V switching power supplies.

FAQ

What is the exact pin configuration of TLVH432CPKG3 in the SOT-89 package?

The TLVH432CPKG3 uses Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE - a reversed pinout versus TLVH431PK devices. This configuration is explicitly defined in Figure 4-7 of the TI datasheet SLVS555N and ensures correct feedback loop polarity when used with optocouplers in flyback converters.

Does TLVH432CPKG3 require an external output capacitor for stability?

No, TLVH432CPKG3 is internally compensated and remains stable without an output capacitor between CATHODE and ANODE. However, if a capacitor is added for noise filtering, Figures 5-15 through 5-17 in the datasheet provide phase-margin guidance for selecting values up to 10 nF depending on cathode voltage and load conditions.

What is the minimum cathode current required for regulation in TLVH432CPKG3?

The TLVH432CPKG3 requires a minimum cathode current of 100 μA to maintain regulation across its full operating temperature range (–40°C to +125°C). Below this threshold, gain drops significantly, causing poor reference tracking and increased output impedance.

How does the reference voltage tolerance of TLVH432CPKG3 impact output accuracy in a 3.3 V SMPS design?

With ±1% initial tolerance at 25°C and ±31 mV total deviation over –40°C to +125°C (Q grade), TLVH432CPKG3 contributes directly to overall output voltage error. In a typical 3.3 V flyback using 1.24 V reference and 2:1 resistor divider, this yields ±1.2% system-level output tolerance before accounting for optocoupler CTR drift or resistor tolerances.

Can TLVH432CPKG3 replace TL431 in existing designs?

TLVH432CPKG3 can replace TL431 only in SOT-89 layouts with pinout adaptation - TL431 uses different pin assignments and has 2.5 V reference. Direct substitution requires redesigning the feedback divider (to scale 3.3 V → 1.24 V instead of → 2.5 V) and verifying cathode current compliance, as TLVH432CPKG3 operates down to 100 μA versus TL431's 1 mA minimum.