Texas Instruments TLVH431ACDBVR

Overview

TLVH431ACDBVR from Texas Instruments is a low-voltage adjustable precision shunt regulator IC with 1.24 V reference voltage, ±0.5% initial tolerance at 25°C, and operation down to 100 μA cathode current. It delivers 0.25 Ω typical dynamic impedance and operates across –40°C to +125°C for use in isolated flyback SMPS feedback loops and voltage monitoring circuits.

For engineers reviewing the TLVH431ACDBVR datasheet, TLVH431ACDBVR pinout, TLVH431ACDBVR application, or TLVH431ACDBVR equivalent, key selection criteria include reference accuracy grade (A = 1%), SOT-23-3 package footprint, cathode current range (100 μA–70 mA), thermal stability over industrial temperature range, and compatibility with optocoupler-based secondary-side regulation.

Technical Context

The TLVH431ACDBVR implements a three-terminal shunt-regulator architecture with an internal 1.24 V bandgap reference and high-gain NPN-based error amplifier driving a Darlington output stage. Its open-loop mode enables comparator functionality with integrated reference, while closed-loop operation-via resistive feedback between cathode and reference pins-achieves precise voltage regulation from 1.24 V to 18 V.

Unlike the TL431, it operates at lower headroom (≥1.24 V) and supports sub-mA cathode currents, making it suitable for low-power 3.3 V and 5 V systems. Internal compensation ensures stability without external capacitors, though phase margin vs. capacitive load is characterized up to 100 nF for design validation.

Key Specifications

Pinout & Package

SOT-23-3 package (2.92 mm × 1.30 mm body size), surface-mount, RoHS-compliant. Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431IDBVR, TLVH431ACDBVR provides tighter initial accuracy for precision feedback loops; compared with TLVH431BQDBVR, it trades slightly higher V_REF drift over temperature for lower unit cost while maintaining identical industrial temperature rating and package compatibility.

Availability

TLVH431ACDBVR is available at Aetrix Electronics and suitable for isolated SMPS feedback, power-rail monitoring, and low-leakage voltage reference applications requiring stable component supply, traceable sourcing, and lifecycle continuity support.

Supply support for TLVH431ACDBVR 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 signal chain technologies.

The TLVH431 family was designed for low-voltage, high-accuracy shunt regulation in space-constrained and thermally demanding applications-including isolated power supplies, battery management, and industrial sensing-where legacy references like TL431 fall short.

FAQ

What is the reference voltage tolerance of TLVH431ACDBVR at 25°C?

The TLVH431ACDBVR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal V_REF with a range of 1.234 V to 1.246 V. This A-grade specification is confirmed in Section 5.6 of the TI SLVS555N datasheet and applies specifically to the 'A' suffix variant in SOT-23-3 packaging. TLVH431ACDBVR maintains this accuracy under recommended operating conditions with 10 mA cathode current.

Does TLVH431ACDBVR require an external capacitor for stability?

No, TLVH431ACDBVR is internally compensated and does not require an external capacitor between cathode and anode for basic stability. Section 7.3 of the datasheet confirms its unity-gain stable design. However, if an output capacitor is used for filtering or transient response shaping, Figures 5-15 through 5-17 provide phase-margin vs. capacitive-load data to guide selection-up to 100 nF is validated for TLVH431ACDBVR in SOT-23-3.

What is the minimum cathode current needed for regulation in TLVH431ACDBVR?

The minimum cathode current required for regulation in TLVH431ACDBVR is 100 μA, as specified in Section 5.5 (IK(min)) of the datasheet under full temperature range conditions. At temperatures up to +125°C, IK(min) remains ≤100 μA, enabling reliable startup and regulation in ultra-low-power applications such as battery-backed monitoring circuits where TLVH431ACDBVR draws negligible quiescent current.

How does TLVH431ACDBVR differ from TL431 in practical design?

TLVH431ACDBVR differs from TL431 by supporting lower operating voltage (1.24 V vs. 2.5 V reference), lower minimum cathode current (100 μA vs. 1 mA), and wider temperature range (–40°C to +125°C standard). These differences allow TLVH431ACDBVR to regulate 3.3 V and lower rails directly and operate in energy-constrained systems where TL431 would fail to start or exhibit poor regulation. The pinout is incompatible, requiring PCB redesign.

Can TLVH431ACDBVR be used as a comparator, and what is its response behavior?

Yes, TLVH431ACDBVR can be used as a comparator in open-loop configuration, leveraging its integrated 1.24 V reference and high open-loop gain. Section 7.4.1 and Figure 5-4 confirm sharp turn-on characteristics with fast transition (<100 ns typical) when the REF pin voltage crosses V_REF. In this mode, TLVH431ACDBVR sinks cathode current only above threshold, enabling clean digital-level outputs for UVLO or OVP detection without external components.