Texas Instruments TLVH431BIPKG3

Overview

TLVH431BIPKG3 from Texas Instruments is a precision 3-terminal adjustable shunt voltage reference with 0.5% initial tolerance at 25°C, 1.24V nominal reference voltage, and operation down to 1.24V cathode-anode voltage. It delivers stable regulation across –40°C to +125°C, supports cathode currents from 100μA to 70mA, and features 0.25Ω typical dynamic impedance-enabling accurate secondary-side feedback in isolated 3.3V flyback SMPS designs.

For engineers reviewing the TLVH431BIPKG3 datasheet, TLVH431BIPKG3 pinout, TLVH431BIPKG3 application, or TLVH431BIPKG3 equivalent, key selection considerations include its B-grade reference accuracy, SOT-89-3 package thermal performance (R_θJA = 52°C/W), ultra-low I_REF (0.1–0.5μA), and compatibility with optocoupler-based isolated feedback loops requiring <2.7V minimum regulated output.

Technical Context

The TLVH431BIPKG3 implements an internal bandgap reference and high-gain NPN-based error amplifier driving a Darlington sink output stage. Its open-loop comparator mode enables precise voltage monitoring without external references, while closed-loop operation with resistive divider feedback achieves adjustable output regulation from V_REF (1.24V) to 18V.

It is internally compensated for stability without an output capacitor, though capacitive load interaction is characterized up to 100nF. The device's sharp turn-on characteristic and low 100μA minimum cathode current make it a direct low-voltage replacement for Zener diodes in space-constrained, thermally demanding applications.

Key Specifications

Pinout & Package

SOT-89-3 package (4.50 mm × 2.50 mm body), surface-mount, thermally enhanced with exposed pad (not electrically connected). Designed for high-power-density PCB layouts requiring efficient heat transfer to copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431BIDBZR, TLVH431BIPKG3 offers 4× lower thermal resistance for higher power reliability; compared with TLVH432BIPK, it provides identical performance with standard pinout-avoiding layout rework while maintaining B-grade precision and 125°C operation.

Availability

TLVH431BIPKG3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and test equipment requiring stable component supply with guaranteed long-term availability and full traceability.

Supply support for TLVH431BIPKG3 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and energy efficiency.

The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in isolated and non-isolated power conversion-addressing limitations of legacy TL431 in 1.8V–3.3V systems and automotive extended-temperature applications.

FAQ

What is the maximum cathode voltage rating for TLVH431BIPKG3?

The absolute maximum cathode-to-anode voltage (V_KA) for TLVH431BIPKG3 is 20 V. Operating beyond this risks permanent damage. For reliable long-term operation, TI specifies 18 V as the maximum recommended cathode voltage under continuous conditions per Section 5.3 of the datasheet. This limit ensures safe junction temperature and maintains 0.5% reference accuracy across the full –40°C to +125°C range in the TLVH431BIPKG3.

Does TLVH431BIPKG3 require an output capacitor for stability?

No, TLVH431BIPKG3 is internally compensated and stable without an output capacitor between cathode and anode. This eliminates capacitor footprint, cost, and ESR-related instability risks. However, if a capacitor is added for filtering or transient response, TI provides phase margin vs. capacitive load curves (Figures 5-15 to 5-17) showing stable operation up to 100 nF at V_KA = 5 V. Always verify stability with actual layout parasitics when using >10 nF.

How does the REF pin current affect TLVH431BIPKG3 accuracy?

The REF pin draws 0.1–0.5 μA (typical 0.2 μA), which flows through the upper feedback resistor (R1) and introduces a voltage error: ΔV = I_REF × R1. For example, with R1 = 100 kΩ, error is up to 50 mV-exceeding the 1.24V reference itself. To maintain accuracy, use lower R1 values (e.g., 10 kΩ yields ≤5 mV error) or compensate mathematically in system calibration. This current is temperature-stable and specified across –40°C to +125°C in TLVH431BIPKG3.

Can TLVH431BIPKG3 replace a standard TL431 in existing designs?

TLVH431BIPKG3 can replace TL431 only if the circuit operates at ≥1.24V cathode-anode voltage and tolerates the different pinout (TL431: Cathode-Anode-Ref; TLVH431BIPKG3: Cathode-Ref-Anode). It offers lower V_REF (1.24V vs. 2.5V), tighter B-grade tolerance (0.5% vs. 1%), and lower I_K(min) (100μA vs. 1mA), but requires verifying feedback divider recalculations and thermal design due to SOT-89's distinct R_θJA. Direct substitution without analysis may cause regulation failure.

What is the minimum cathode current needed for regulation in TLVH431BIPKG3?

The minimum cathode current (I_K(min)) required for TLVH431BIPKG3 to enter regulation is 100 μA at 25°C, with a maximum of 120 μA over the full –40°C to +125°C range. Below this, the internal amplifier lacks sufficient bias current, causing gain collapse and loss of reference accuracy. In flyback designs, ensure the optocoupler LED current plus any parallel paths meets this threshold even at light loads-TI recommends designing for ≥150 μA margin to guarantee stability across temperature and unit variation in TLVH431BIPKG3.