Texas Instruments TLVH431AQPKG3

Overview

TLVH431AQPKG3 from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-89-3 package, delivering 1.24 V reference voltage with ±0.5% initial tolerance at 25°C, 100 μA minimum cathode current for regulation, and operation across –40°C to +125°C. It serves as an integrated voltage reference and error amplifier in isolated flyback SMPS feedback loops, replacing Zener diodes with lower leakage and sharper turn-on.

For engineers reviewing the TLVH431AQPKG3 datasheet, TLVH431AQPKG3 pinout, TLVH431AQPKG3 application, or TLVH431AQPKG3 equivalent, key selection criteria include reference accuracy grade (Q = automotive temp range), cathode current capability (100 μA–70 mA), dynamic impedance (0.25 Ω), thermal stability (±31 mV over –40°C to +125°C), and SOT-89 package compatibility with high-power dissipation requirements.

Technical Context

The TLVH431AQPKG3 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, enabling closed-loop regulation via external resistor dividers or open-loop comparator operation.

Unlike the TL431, it operates down to 1.24 V cathode-anode voltage and achieves stable regulation without output capacitance due to internal compensation. The Q-grade variant is qualified for automotive applications with full –40°C to +125°C operation and specified VREF deviation of ±31 mV.

Key Specifications

Pinout & Package

SOT-89-3 package (4.50 mm × 2.50 mm), thermally enhanced for up to 52°C/W junction-to-ambient resistance; suitable for medium-power shunt regulation with PCB copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AQPKG3, TLVH431BQPKG3 offers marginally tighter VREF binning while TLVH432AQPKG3 delivers identical regulation performance at the cost of mandatory board rework - neither is a drop-in replacement, but both serve as functional alternatives in new designs where pinout or grading flexibility is acceptable.

Availability

TLVH431AQPKG3 is available at Aetrix Electronics and suitable for automotive power management, industrial SMPS feedback, and precision voltage monitoring requiring stable component supply across extended temperature ranges.

Supply support for TLVH431AQPKG3 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 precision analog ICs and automotive-qualified components.

The TLVH431 family was designed for high-accuracy, low-voltage shunt regulation in safety-critical power systems - particularly targeting secondary-side feedback in isolated DC/DC converters and robust voltage supervision in harsh-temperature environments.

FAQ

What is the reference voltage tolerance of TLVH431AQPKG3 at 25°C?

The TLVH431AQPKG3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal VREF with a range of 1.234 V to 1.246 V. This A-grade tolerance is confirmed in Section 5.6 of the TI datasheet SLVS555N and applies specifically to the AQ suffix variant. The Q temperature grade ensures this accuracy holds across –40°C to +125°C operation.

Does TLVH431AQPKG3 require an output capacitor for stability?

No, TLVH431AQPKG3 is internally compensated and remains stable without an output capacitor between CATHODE and ANODE. This is explicitly stated in Section 7.3 of the datasheet. However, if a capacitor is added for noise filtering, Figures 5-15 through 5-17 provide phase-margin guidance for capacitive loads up to 100 nF depending on cathode voltage and current.

What is the minimum cathode current needed for regulation in TLVH431AQPKG3?

The TLVH431AQPKG3 requires a minimum cathode current of 100 μA to maintain regulation, as specified in Sections 5.5–5.7 under IK(min). This value is guaranteed across the full –40°C to +125°C temperature range for the Q-grade device. Below this threshold, gain drops significantly and regulation becomes unreliable.

How does TLVH431AQPKG3 differ from TLVH432AQPKG3?

TLVH431AQPKG3 and TLVH432AQPKG3 share identical electrical specifications and thermal ratings, but differ in pinout: TLVH431AQPKG3 uses Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE, whereas TLVH432AQPKG3 uses Pin 1 = REF, Pin 2 = ANODE, Pin 3 = CATHODE. This reversal makes them non-interchangeable without PCB modification.

Can TLVH431AQPKG3 be used as a comparator?

Yes, TLVH431AQPKG3 functions as a comparator in open-loop configuration - applying voltage to the REF pin while supplying ≥100 μA cathode current. Its high open-loop gain produces sharp switching behavior, as documented in Section 7.4.1 and Figure 5-4. The integrated 1.24 V reference eliminates need for external reference components in level-detection circuits.