Texas Instruments TLV431ACLPE3

Overview

TLV431ACLPE3 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±1% initial tolerance at 25°C, and operation from 1.24 V to 6 V output range. It delivers 0.25 Ω typical dynamic impedance, 80 µA typical minimum cathode current, and supports secondary-side regulation in isolated flyback SMPSs for 3.3 V systems.

For engineers reviewing the TLV431ACLPE3 datasheet, TLV431ACLPE3 pinout, TLV431ACLPE3 application, or TLV431ACLPE3 equivalent, key selection considerations include reference accuracy over temperature (±6 mV from –40°C to 85°C), ultra-low cathode current requirement, SC-70 package footprint, and compatibility with optocoupler-based feedback loops in compact power supplies.

Technical Context

The TLV431ACLPE3 implements a three-terminal adjustable shunt reference architecture with an internal bandgap reference and high-gain NPN-based error amplifier. Its open-loop comparator mode enables precise voltage monitoring, while closed-loop configuration with external resistors achieves stable voltage regulation down to 1.24 V.

It operates with cathode-to-anode voltage (VKA) from 1.24 V to 6 V and requires ≥55 µA cathode current for regulation across its full industrial temperature range (–40°C to 85°C). The device is internally compensated and stable without an output capacitor, supporting direct integration into space-constrained feedback networks.

Key Specifications

Pinout & Package

TLV431ACLPE3 is housed in a 6-pin SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller than SOT-23-3 - with exposed substrate connection requiring tie to anode or floating per TI specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BCLPE3, TLV431ACLPE3 trades 0.5% accuracy for lower cost in volume industrial power supplies; versus TLVH431ACDBVR, it offers 40% smaller footprint and lower quiescent current but sacrifices voltage headroom and current drive capacity.

Availability

TLV431ACLPE3 is available at Aetrix Electronics and suitable for isolated flyback SMPS regulation, precision voltage monitoring, and low-voltage Zener replacement requiring stable component supply across automotive infotainment, industrial PLCs, and IoT edge devices.

Supply support for TLV431ACLPE3 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 precision analog ICs and power management solutions.

The TLV431 family was designed specifically for low-voltage, high-accuracy shunt regulation in space-constrained power supplies and feedback-critical systems, targeting 1.24 V–6 V adjustable references where legacy TL431 cannot operate.

FAQ

What is the reference voltage tolerance of TLV431ACLPE3 at 25°C?

The TLV431ACLPE3 has a reference voltage tolerance of ±1% at 25°C, corresponding to a V_REF range of 1.228 V to 1.252 V. This specification is confirmed in Section 5.6 of the official TI datasheet SLVS139Z. The ±1% grade distinguishes TLV431ACLPE3 from the tighter ±0.5% TLV431B and looser ±1.5% base TLV431 variants. TLV431ACLPE3 maintains this accuracy across its rated industrial temperature range.

Which package does TLV431ACLPE3 use, and what are its dimensions?

TLV431ACLPE3 uses the SC-70 (DCK) package, a 6-pin surface-mount outline measuring 2.0 mm × 1.5 mm. Per TI's Package Information table, this footprint is 40% smaller than the standard SOT-23-3. Pin 1 is CATHODE, Pin 3 is REF, Pin 6 is ANODE, and Pins 4–5 are NC. The substrate (Pin 2) must be connected to ANODE or left open. TLV431ACLPE3 is not offered in SOT-23-3, TO-92, or SOIC variants.

Can TLV431ACLPE3 replace a standard Zener diode in low-voltage circuits?

Yes, TLV431ACLPE3 is explicitly designed as a precision Zener diode replacement for voltages from 1.24 V to 6 V. Unlike fixed Zeners, it offers ±1% reference accuracy, 0.25 Ω dynamic impedance, and adjustable output via two external resistors. Its 80 µA minimum cathode current enables operation in ultra-low-power circuits where traditional Zeners fail. TI's datasheet cites "Zener replacement" as a primary application, confirming direct functional equivalence with superior performance.

What is the minimum cathode current required for regulation in TLV431ACLPE3?

The TLV431ACLPE3 requires a minimum cathode current (I_K(min)) of 55 µA to 80 µA for stable regulation, depending on temperature and operating conditions. At 25°C, typical I_K(min) is 80 µA; over the full –40°C to 85°C range, it remains ≤80 µA for the 'I' grade. This value is specified in Section 5.6 of the TI datasheet and is significantly lower than the 1 mA required by TL431, enabling efficient operation in micro-power designs.

How does TLV431ACLPE3 behave in open-loop comparator mode?

In open-loop mode, TLV431ACLPE3 functions as a comparator with integrated 1.24 V reference: when voltage at the REF pin exceeds V_REF, the CATHODE sinks current; below V_REF, it remains off. It requires ≥55 µA cathode current to ensure sufficient gain and fast response. TI's datasheet confirms this use case in Section 7.4.1 and Figure 8-2, noting that trip-point accuracy depends on V_REF tolerance and overdrive margin. TLV431ACLPE3's low I_REF (0.15–0.5 µA) minimizes loading on the input divider.