Texas Instruments TLVH432BQPK

Overview

TLVH432BQPK from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-89-3 package, providing 1.24 V reference voltage with ±0.5% initial tolerance at 25°C, 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 requiring tight regulation below 3.3 V.

For engineers reviewing the TLVH432BQPK datasheet, TLVH432BQPK pinout, TLVH432BQPK application, or TLVH432BQPK equivalent, key selection criteria include cathode current range (100 μA–70 mA), thermal stability over –40°C to +125°C, ultra-low reference input current (0.1–0.5 μA), and compatibility with optocoupler-based secondary-side regulation circuits.

Technical Context

The TLVH432BQPK implements a three-terminal shunt topology with internal 1.24 V bandgap reference and high-gain NPN-based error amplifier. Its functional block includes a reference node (REF), current-sinking cathode (CATHODE), and common return (ANODE), enabling closed-loop regulation via external resistor dividers or open-loop comparator operation.

Unlike the TLVH431, the TLVH432BQPK uses reversed pinout in SOT-89: Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF - a configuration optimized for PCB layout in compact power supply feedback networks where cathode routing dominates trace width and thermal path design.

Key Specifications

Pinout & Package

SOT-89-3 package (4.50 mm × 2.50 mm body) with exposed thermal pad; designed for surface-mount assembly and efficient heat transfer to PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH432BIDBZR and TLVH431BQPK, the TLVH432BQPK uniquely combines SOT-89 thermal performance (52 °C/W), grade-B precision (±0.5%), and TLVH432-specific pinout - making it optimal for new flyback designs prioritizing thermal headroom and layout simplicity.

Availability

TLVH432BQPK is available at Aetrix Electronics and suitable for isolated power supplies, precision analog references, and industrial voltage monitoring systems requiring stable component supply across extended temperature ranges.

Supply support for TLVH432BQPK 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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability components.

The TLVH432BQPK belongs to TI's precision shunt regulator product line, engineered for secondary-side feedback in low-voltage isolated DC/DC converters and high-accuracy voltage reference applications across automotive, industrial, and telecom end equipment.

FAQ

What is the exact pinout configuration of TLVH432BQPK in the SOT-89 package?

The TLVH432BQPK uses Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF - a reversed arrangement versus TLVH431 variants. This layout places the high-current cathode on the leadframe tab side, optimizing thermal conduction and reducing trace inductance in feedback paths. Always verify against Figure 4-7 in the SLVS555N datasheet before PCB layout.

How does TLVH432BQPK achieve ±0.5% reference voltage accuracy?

The TLVH432BQPK achieves ±0.5% V_REF accuracy at 25°C through laser-trimmed bandgap circuitry and matched transistor pairs in its internal reference core. This B-grade tolerance is verified during final test and applies across the full operating current range (100 μA–70 mA) and voltage range (1.24 V–18 V), as specified in Section 5.7 of the datasheet.

Can TLVH432BQPK operate with cathode current below 100 μA?

No - TLVH432BQPK requires ≥100 μA cathode current (I_K(min)) to maintain regulation, as confirmed in Section 5.3 and Figure 5-5. Operation below this threshold results in degraded gain, increased V_REF deviation (>±5%), and potential loss of regulation. For ultra-low-current applications, consider TLV431 variants with 60 μA minimum.

What is the maximum power dissipation capability of TLVH432BQPK?

With R_θJA = 52 °C/W and T_J(max) = 150°C, TLVH432BQPK can dissipate up to 1.02 W at 25°C ambient (P_D = (150 – 25)/52). Derating is required above 25°C; at 85°C ambient, max dissipation drops to 1.25 W × (1 – (85–25)/125) = ~625 mW. Thermal pad soldering to ≥1 in² 2 oz copper is recommended.

Is TLVH432BQPK compatible with optocouplers in isolated feedback designs?

Yes - TLVH432BQPK is explicitly validated for use with PC817, SFH615A, and similar optocouplers in flyback SMPS feedback loops. Its low 0.5 μA reference current and sharp turn-on enable stable loop response with <1% output error across line, load, and temperature - as demonstrated in Figure 8-1 and Application Report SLUA671.