Texas Instruments TLV431AIDBVT

Overview

TLV431AIDBVT from Texas Instruments is a low-voltage adjustable precision shunt regulator IC used as a 3-terminal voltage reference in feedback loops of isolated DC-DC converters, Zener replacements, and comparator circuits. It delivers 1.24 V reference voltage with ±1% tolerance at 25°C, operates down to 1.24 V cathode-anode voltage (VKA), supports 0.1–15 mA cathode current (IK), and features 0.25 Ω typical dynamic impedance - enabling stable regulation in 3.3 V flyback SMPS secondary-side control.

For engineers reviewing the TLV431AIDBVT datasheet, TLV431AIDBVT pinout, TLV431AIDBVT application, or TLV431AIDBVT equivalent, key selection criteria include reference accuracy over temperature (±11 mV from –40°C to 125°C), ultra-low 80 µA typical minimum cathode current for regulation, SC-70 package footprint (2.0 mm × 1.5 mm), and compatibility with optocoupler-based isolated feedback topologies.

Technical Context

The TLV431AIDBVT integrates an internal 1.24 V bandgap reference and high-gain transconductance amplifier driving a Darlington sink output stage. Its functional modes include open-loop comparator operation (with integrated reference) and closed-loop shunt regulation via external resistor divider feedback between cathode and reference pins.

It achieves stable regulation without mandatory output capacitance due to internal compensation, but phase margin versus capacitive load is characterized up to 1 nF for design validation. The device requires ≥0.5 µA reference pin current and ≥80 µA cathode current to maintain linear operation across –40°C to 125°C (Q-grade).

Key Specifications

Pinout & Package

TLV431AIDBVT is housed in a 6-pin SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller than SOT-23-3 - with thermal resistance R_θJA = 87°C/W. Pin 1 is CATHODE, Pin 3 is REF, Pin 6 is ANODE; Pins 2 and 4–5 are NC (no internal connection). Substrate (Pin 2) must be connected to ANODE or left open.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BIDBVT, TLV431AIDBVT trades 0.5% accuracy for lower cost in non-calibrated power supervision; compared with TLVH431IDBVR, it offers smaller SC-70 size and lower quiescent current but sacrifices voltage headroom and current capacity.

Availability

TLV431AIDBVT is available at Aetrix Electronics and suitable for isolated SMPS designs, battery management systems, and precision voltage monitoring applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TLV431AIDBVT 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, embedded processing, and power management technologies, with leadership in precision analog ICs and power conversion solutions.

The TLV431 family was designed specifically for low-voltage, high-accuracy shunt regulation and comparator functions in space- and power-constrained applications - targeting 3.3 V/5 V isolated power supplies, portable electronics, and industrial control systems.

FAQ

What is the reference voltage tolerance of TLV431AIDBVT at 25°C?

The TLV431AIDBVT has a reference voltage (VREF) tolerance of ±1% at 25°C, meaning its nominal 1.24 V output falls within 1.228 V to 1.252 V under standard test conditions. This tolerance is confirmed in Section 5.6 of the TI datasheet SLVS139Z and applies specifically to the 'A' grade variant, distinguishing it from the tighter ±0.5% TLV431B and looser ±1.5% base TLV431 versions.

Can TLV431AIDBVT operate in a 3.3 V isolated flyback converter?

Yes, TLV431AIDBVT is explicitly validated for 3.3 V isolated flyback converters, as shown in Figure 8-1 of the datasheet. When paired with an optocoupler, it regulates output by comparing a resistor-divided sample to its 1.24 V reference. The minimum cathode-anode voltage (VKA) of 1.24 V plus optocoupler LED forward drop (~1.4 V) enables stable regulation down to ~2.7 V output - well within 3.3 V system margins.

What is the minimum cathode current required for regulation in TLV431AIDBVT?

The TLV431AIDBVT requires a minimum cathode current (IK(min)) of 80 µA typical to maintain regulation, as specified in Section 5.6 of the datasheet. This value holds across the full –40°C to 125°C temperature range for the Q-grade version. Supplying less than this may result in degraded gain, slow response, or loss of regulation - especially critical in low-power standby modes of SMPS designs.

Does TLV431AIDBVT require an output capacitor for stability?

No, TLV431AIDBVT is internally compensated and does not require an output capacitor to maintain stability in standard shunt regulator configurations. However, if a capacitive load is added (e.g., for noise filtering), Figure 5-19 in the datasheet provides phase margin vs. capacitive load data - recommending ≤100 pF for robust stability at 5 V VKA, with derating needed for larger values.

What package type is used for TLV431AIDBVT and how does it compare to SOT-23-3?

TLV431AIDBVT uses the SC-70 (DCK) package - a 6-pin surface-mount outline measuring 2.0 mm × 1.5 mm. Per TI documentation, this offers a 40% smaller footprint than the 3-pin SOT-23-3 package. While pin count differs, the SC-70 variant maintains functional equivalence for shunt regulation and includes dedicated ANODE, CATHODE, and REF terminals with NC pins for flexibility and substrate connection.