Texas Instruments TLVH431AQDBZTG4

Overview

TLVH431AQDBZTG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±0.5% initial tolerance at 25°C (A-grade), and operation down to 100 μA cathode current. It delivers stable voltage reference and error amplification in isolated flyback SMPS feedback loops, data converter references, and power-rail monitoring circuits.

For engineers reviewing the TLVH431AQDBZTG4 datasheet, TLVH431AQDBZTG4 pinout, TLVH431AQDBZTG4 application, or TLVH431AQDBZTG4 equivalent, key selection criteria include its 1.24 V reference accuracy, ultra-low 100 μA minimum regulation current, 0.25 Ω dynamic impedance, –40°C to +125°C Q-grade temperature range, and SOT-23-3 (DBZ) package compatibility with space-constrained industrial and automotive power designs.

Technical Context

The TLVH431AQDBZTG4 implements a precision bandgap reference and high-gain NPN-based error amplifier in a 3-terminal shunt topology. Its internal Darlington output stage enables sharp turn-on behavior and stable regulation with no external compensation required, even without an output capacitor between cathode and anode.

It operates in two distinct functional modes: open-loop comparator mode (using integrated 1.24 V reference for threshold detection) and closed-loop shunt regulator mode (with resistive feedback from cathode to reference pin to set output voltage from 1.24 V to 18 V). The device is specified for Q-grade (–40°C to +125°C) operation and supports secondary-side regulation in 3.3 V isolated flyback converters when paired with an optocoupler.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: 2.92 mm × 1.30 mm body, 3-pin surface-mount, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AQDBZTG4, TLVH431BQDBZTG4 delivers superior thermal stability for precision analog systems, while TLV431ACDBVR offers lower cost at the expense of automotive qualification and package compatibility - making TLVH431AQDBZTG4 the optimal balance of accuracy, temperature range, and SOT-23-3 footprint for industrial and automotive power management.

Availability

TLVH431AQDBZTG4 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and telecom DC-DC converters requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for TLVH431AQDBZTG4 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 deep expertise in power management and precision analog ICs.

The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in isolated and non-isolated power supplies, replacing Zener diodes and enabling compact, stable feedback loops in automotive, industrial, and computing applications.

FAQ

What is the reference voltage tolerance of TLVH431AQDBZTG4 at 25°C?

The TLVH431AQDBZTG4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal V_REF with min/max bounds of 1.234 V and 1.246 V. This A-grade specification is confirmed in Section 5.6 of the official TI datasheet SLVS555N and applies specifically to the Q-temperature variant (–40°C to +125°C) of the DBZ package. TLVH431AQDBZTG4 maintains this tolerance across its full operating range with defined drift limits.

Can TLVH431AQDBZTG4 operate with cathode currents below 100 µA?

No - TLVH431AQDBZTG4 requires a minimum cathode current of 100 µA to maintain regulation and specified reference accuracy. Below this threshold, open-loop gain drops significantly, causing degraded line/load regulation and increased V_REF deviation. The datasheet specifies IK(min) = 60–100 µA depending on grade and temperature, and TLVH431AQDBZTG4 is characterized for reliable operation starting at 100 µA across its full –40°C to +125°C range.

What is the correct pin configuration for TLVH431AQDBZTG4 in SOT-23-3 (DBZ) package?

TLVH431AQDBZTG4 uses the standard TLVH431 DBZ pinout: Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF. This is explicitly shown in Figure 4-4 of the TI datasheet SLVS555N and differs from TLVH432 DBZ (Pin 1 = REF, Pin 2 = CATHODE, Pin 3 = ANODE). Confirming this mapping is critical - incorrect PCB layout will prevent regulation or damage the device.

Does TLVH431AQDBZTG4 require an output capacitor for stability?

No - TLVH431AQDBZTG4 is internally compensated and remains stable without an output capacitor between cathode and anode. This is a key design advantage over many error amplifiers and is verified in Section 7.3 and Figure 5-15 through 5-17 of the datasheet. However, if a capacitor is added for noise filtering, its value must be selected per the phase-margin curves to avoid oscillation - especially with capacitive loads >1 nF.

How does TLVH431AQDBZTG4 differ from TL431 in practical design?

TLVH431AQDBZTG4 operates down to 1.24 V reference (vs TL431's 2.5 V), supports 100 µA minimum cathode current (vs 1 mA), and functions in 3.3 V and lower systems where TL431 cannot regulate. It also features lower dynamic impedance (0.25 Ω vs ~0.5 Ω) and Q-grade temperature rating. These differences make TLVH431AQDBZTG4 the preferred choice for modern low-voltage, high-efficiency isolated SMPS and battery-powered instrumentation - unlike TL431, which remains suitable for legacy 5 V/12 V designs.