Texas Instruments TLVH431BQLPE3

Overview

TLVH431BQLPE3 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 0.5% reference voltage tolerance at 25°C, 1.24 V nominal reference voltage, and operation down to 1.24 V cathode-to-anode voltage. It delivers stable regulation across –40°C to +125°C, supports 100 μA to 70 mA cathode current, and features 0.25 Ω typical dynamic impedance-enabling accurate secondary-side feedback in isolated 3.3 V flyback SMPS designs.

For engineers reviewing the TLVH431BQLPE3 datasheet, TLVH431BQLPE3 pinout, TLVH431BQLPE3 application, or TLVH431BQLPE3 equivalent, key selection criteria include initial VREF tolerance (0.5% B-grade), thermal stability over automotive temperature range (–40°C to +125°C), ultra-low minimum cathode current (100 μA), SC-70 package footprint, and compatibility with optocoupler-based isolated feedback loops.

Technical Context

The TLVH431BQLPE3 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 when sufficient cathode current (≥100 μA) flows and feedback is applied between CATHODE and REF terminals.

In open-loop mode, it functions as a comparator with integrated reference; in closed-loop configuration with two external resistors, it regulates output voltage from 1.24 V to 18 V. The device is internally compensated and stable without an output capacitor, though capacitive load effects on phase margin are characterized per Figure 5-15 through 5-17.

Key Specifications

Pinout & Package

TLVH431BQLPE3 is packaged in the SC-70 (DCK) outline: 2.00 mm × 1.25 mm body, 6-pin surface-mount package with exposed pad not connected internally. Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF, Pins 4 and 5 = NC, Pin 6 = substrate connection (must tie to ANODE or leave open).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431BQLPE3, TLVH431BIDCKR offers identical accuracy and package but reduced temperature range, while TLVH432BQPK provides same grade and thermal performance in a larger, thermally superior package with inverted pinout-requiring schematic and layout revision.

Availability

TLVH431BQLPE3 is available at Aetrix Electronics and suitable for automotive power management, industrial sensor signal conditioning, and isolated DC-DC converter feedback requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TLVH431BQLPE3 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 delivering analog and embedded processing solutions, with leadership in precision analog, power management, and interface technologies.

The TLVH431 family was designed for low-voltage, high-accuracy shunt regulation in space-constrained and thermally demanding applications-including automotive infotainment power supplies, industrial PLC I/O modules, and isolated AC/DC adapters.

FAQ

What is the reference voltage tolerance of TLVH431BQLPE3 at 25°C?

The TLVH431BQLPE3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a V_REF range of 1.234 V to 1.246 V. This B-grade specification is confirmed in Section 5.7 of the TI datasheet SLVS555N and applies specifically to the TLVH431B variant in the SC-70 package. The tolerance remains stable across the full –40°C to +125°C operating range, with total deviation limited to 31 mV for the Q-grade version.

Can TLVH431BQLPE3 operate with a cathode-to-anode voltage below 1.24 V?

No, TLVH431BQLPE3 requires a minimum cathode-to-anode voltage (V_KA) of 1.24 V to enter regulation and maintain reference accuracy. Below this threshold, the internal amplifier cannot bias correctly, and the device ceases to regulate. The datasheet specifies V_KA ≥ V_REF (1.24 V) in Recommended Operating Conditions (Section 5.3), and Figure 5-3 confirms sharp turn-on only above ~1.25 V at 25°C.

What is the function of Pin 6 on TLVH431BQLPE3?

Pin 6 on TLVH431BQLPE3 is the substrate connection, electrically isolated from all internal circuitry. Per the Pin Functions table and Figure 4-2 in SLVS555N, it must be either connected to the ANODE (Pin 2) or left unconnected-it must never be left floating. This mechanical tie stabilizes thermal and ESD behavior but carries no signal or power function.

How does TLVH431BQLPE3 differ from TL431 in practical design?

TLVH431BQLPE3 operates down to 1.24 V (vs TL431's 2.5 V), draws only 100 μA minimum cathode current (vs 1 mA), and achieves 0.5% initial tolerance (vs standard TL431's 1%–2%). These differences allow TLVH431BQLPE3 to regulate lower voltages, reduce standby power in always-on circuits, and improve ADC reference accuracy-making it the preferred choice for modern 1.8 V–3.3 V systems where TL431 cannot function.

Is TLVH431BQLPE3 stable without an output capacitor?

Yes, TLVH431BQLPE3 is internally compensated and stable without an output capacitor between CATHODE and ANODE under typical resistive feedback conditions. However, if a capacitive load is added (e.g., for noise filtering), Figures 5-15 to 5-17 in the datasheet provide phase-margin guidance versus capacitance and cathode voltage-capacitors >1 nF at V_KA = 1.25 V require careful selection to avoid instability.