Texas Instruments TLV431AIDBVR

Overview

TLV431AIDBVR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±1% initial tolerance at 25°C, 0.25 Ω typical dynamic impedance, 80 µA typical minimum cathode current, and operation from 1.24 V to 6 V output range. It serves as a Zener replacement or error amplifier in isolated flyback SMPS feedback loops.

For engineers reviewing the TLV431AIDBVR datasheet, TLV431AIDBVR pinout, TLV431AIDBVR application, or TLV431AIDBVR equivalent, key selection criteria include reference accuracy over temperature, cathode current requirements for regulation, dynamic impedance impact on loop stability, SC-70 package footprint constraints, and compatibility with optocoupler-based secondary-side regulation topologies.

Technical Context

The TLV431AIDBVR implements a bandgap-referenced transconductance amplifier driving a Darlington sink output stage. Its internal 1.24 V reference is trimmed for 1% accuracy at 25°C and exhibits ≤12 mV deviation across 0°C to 70°C (TLV431AC grade). The device operates in two functional modes: open-loop comparator (with integrated reference) and closed-loop shunt regulator - both requiring ≥55 µA cathode current to maintain linear operation.

Unlike the TL431, the TLV431AIDBVR achieves regulation down to 1.24 V with only 80 µA typical IK(min), enabling use in 3.3 V and lower-input isolated power supplies. Its 0.25 Ω dynamic impedance and internal compensation allow stable operation without external capacitors, though phase margin degrades above ~1 nF capacitive load depending on VKA.

Key Specifications

Pinout & Package

TLV431AIDBVR uses the SC-70 (DCK) 6-pin package with substrate-connected pin 2. Pin 1 is CATHODE (shunt current input), pin 3 is REF (reference threshold input), and pin 6 is ANODE (common return). Pins 4 and 5 are NC; pin 2 must be connected to ANODE or left floating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BIDBVR, TLV431AIDBVR trades 0.5% accuracy for cost efficiency in commercial-grade power supplies; compared with TLVH431ACDBVR, it offers lower system-level noise and simpler stability design at the expense of voltage and current headroom.

Availability

TLV431AIDBVR is available at Aetrix Electronics and suitable for isolated flyback SMPS regulation, voltage monitoring circuits, adjustable linear regulator references, and Zener diode replacements requiring stable component supply across industrial and consumer production programs.

Supply support for TLV431AIDBVR 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 technologies, with leadership in power management, signal chain, and high-reliability components.

The TLV431x family was designed specifically for low-voltage, precision shunt regulation in space- and power-constrained applications including AC/DC adapters, battery monitors, and isolated DC-DC controllers.

FAQ

What is the reference voltage tolerance of TLV431AIDBVR at 25°C?

The TLV431AIDBVR has a reference voltage tolerance of ±1% at 25°C, meaning its VREF falls between 1.228 V and 1.252 V under nominal conditions. This specification is confirmed in Section 5.6 of the TI datasheet SLVS139Z and applies specifically to the 'A' grade variant. The TLV431AIDBVR maintains this tolerance across its SC-70 package variants and is validated for commercial temperature range operation (0°C to 70°C).

Can TLV431AIDBVR replace a standard Zener diode in low-voltage circuits?

Yes, TLV431AIDBVR is explicitly designed as a precision Zener diode replacement for voltages from 1.24 V to 6 V. Its 0.25 Ω dynamic impedance, sharp turn-on characteristic, and ±1% reference accuracy deliver significantly better regulation than discrete Zeners below 2.5 V. The TLV431AIDBVR also supports higher cathode current (up to 15 mA) and operates reliably with as little as 55 µA minimum cathode current - making it ideal for low-power biasing and clamping in 3.3 V systems.

What is the minimum cathode current required for regulation in TLV431AIDBVR?

The TLV431AIDBVR requires a minimum cathode current (IK(min)) of 55 µA to maintain regulation, with typical performance at 80 µA across 0°C to 70°C. This value is specified in Section 5.6 of the datasheet for the TLV431AC grade, which corresponds to the TLV431AIDBVR's commercial temperature rating. Operating below this threshold risks loss of regulation and degraded gain, especially in open-loop comparator mode.

Does TLV431AIDBVR require an output capacitor for stability?

No, TLV431AIDBVR is internally compensated and stable without an output capacitor between cathode and anode - a key advantage over many op-amp-based references. However, if a capacitive load is added (e.g., for noise filtering), stability depends on load magnitude and cathode voltage: Figure 5-19 shows phase margin remains >45° for ≤1 nF at VKA = 1.25 V, but drops rapidly above that. Always verify loop stability with actual PCB parasitics when adding capacitance.

What package type does TLV431AIDBVR use, and how does it differ from SOT-23-3?

TLV431AIDBVR uses the SC-70 (DCK) 6-pin package measuring 2.0 mm × 1.5 mm - 40% smaller in footprint than the SOT-23-3 package. Unlike SOT-23-3, the SC-70 variant includes dedicated NC pins (4 and 5) and a substrate pin (2) that must be tied to ANODE or left unconnected. The pinout differs fundamentally: CATHODE is on pin 1, REF on pin 3, ANODE on pin 6 - requiring unique PCB layout and preventing direct substitution with SOT-23-3 variants like TLV431ADBZR.