Texas Instruments TLVH431BQLPR

Overview

TLVH431BQLPR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 0.5% reference voltage tolerance at 25°C, 1.24V nominal VREF, 100μA–70mA cathode current range, and operation from –40°C to +125°C. It functions as an integrated voltage reference and error amplifier in isolated flyback SMPS feedback loops, replacing Zener diodes in on-board regulation.

For engineers reviewing the TLVH431BQLPR datasheet, TLVH431BQLPR pinout, TLVH431BQLPR application, or TLVH431BQLPR equivalent, key selection criteria include initial VREF accuracy, thermal stability over industrial temperature range, cathode current headroom for optocoupler drive, and SC-70 package footprint constraints in space-constrained power designs.

Technical Context

The TLVH431BQLPR implements a bandgap-referenced error amplifier with Darlington output stage, enabling precise shunt regulation down to 1.24V. Its open-loop comparator mode provides sharp turn-on behavior with typical 0.25Ω dynamic impedance when used in closed-loop configurations.

It operates with ≥100μA minimum cathode current to maintain regulation, supports adjustable output from VREF to 18V via two external resistors, and features internal compensation eliminating need for output capacitor-though capacitive load stability margins are characterized up to 100nF.

Key Specifications

Pinout & Package

TLVH431BQLPR is packaged in SC-70 (DCK) - 2.00 mm × 1.25 mm body size, 6-pin surface-mount package with exposed substrate connection. Pin 2 connects to substrate and must be tied to ANODE or left floating per design.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431BQLPR, TLVH431BQDBVR offers identical performance in a larger SOT-23-5 package with more robust substrate connection, while TLVH432BQPK delivers superior thermal performance in SOT-89 but requires PCB redesign due to reversed pinout and larger pad area.

Availability

TLVH431BQLPR is available at Aetrix Electronics and suitable for isolated SMPS feedback, precision voltage monitoring, and ADC reference applications requiring stable component supply across automotive, industrial, and telecom end equipment.

Supply support for TLVH431BQLPR 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 solutions, with leadership in power management, signal chain, and high-reliability components.

The TLVH431 family was designed for low-voltage precision shunt regulation in space-constrained, thermally demanding applications such as secondary-side feedback in isolated DC/DC converters and high-accuracy voltage supervision circuits.

FAQ

What is the reference voltage tolerance of TLVH431BQLPR at 25°C?

The TLVH431BQLPR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a VREF range of 1.234 V to 1.246 V. This B-grade accuracy is specified in Section 5.7 of the TI SLVS555N datasheet and applies across the SC-70 (DCK) package variant. The TLVH431BQLPR maintains this tolerance under recommended operating conditions with IK = 10 mA and VKA = VREF.

Does TLVH431BQLPR require an output capacitor for stability?

No, TLVH431BQLPR is internally compensated and does not require an output capacitor between CATHODE and ANODE for basic shunt regulation stability. However, if a capacitive load is added, Figures 5-15 through 5-17 in the datasheet characterize phase margin versus capacitance (up to 100 nF) at multiple cathode voltages, allowing designers to verify stability in specific implementations involving filtering or noise suppression.

What is the minimum cathode current needed for regulation with TLVH431BQLPR?

The TLVH431BQLPR requires a minimum cathode current of 100 μA to maintain regulation, as specified in Section 5.5 (IK(min)) of the datasheet. This value is valid across the full –40°C to +125°C temperature range for the Q-grade version. Below this threshold, open-loop gain drops significantly, degrading regulation accuracy and response time in feedback applications.

How does the SC-70 package of TLVH431BQLPR compare to SOT-23 variants in thermal performance?

The TLVH431BQLPR in SC-70 (DCK) has a junction-to-ambient thermal resistance (RθJA) of 259°C/W, which is higher than the 206°C/W of the SOT-23-3 (DBZ) and 206°C/W of the SOT-23-5 (DBV) packages. This means the SC-70 variant dissipates heat less efficiently; designers must limit power dissipation or enhance PCB copper area to maintain TJ < 125°C under continuous 70 mA cathode load.

Can TLVH431BQLPR be used as a comparator, and what are its key advantages in that mode?

Yes, TLVH431BQLPR can operate as a comparator with integrated 1.24V reference in open-loop configuration. Its advantages include sharp turn-on characteristic due to high open-loop gain (>60 dB), low reference input current (≤0.5 μA), and guaranteed operation down to 1.24V supply - enabling direct monitoring of low-voltage rails without external reference. Section 7.4.1 and Figure 8-2 in the datasheet detail this usage.