Texas Instruments TLV431BCPKG3

Overview

TLV431BCPKG3 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, 0.5% initial tolerance at 25°C, and operation down to 1.24 V cathode-anode voltage. It delivers 0.25 Ω typical dynamic impedance, 80 µA typical minimum cathode current, and supports output voltage adjustment from 1.24 V to 6 V using two external resistors - ideal for secondary-side regulation in compact 3.3 V flyback SMPS designs.

For engineers reviewing the TLV431BCPKG3 datasheet, TLV431BCPKG3 pinout, TLV431BCPKG3 application, or TLV431BCPKG3 equivalent, key selection criteria include reference accuracy over temperature (±4 mV from 0°C to 70°C), ultra-small SC-70 package footprint, open-loop comparator capability with integrated reference, and compatibility with optocoupler-based isolated feedback loops.

Technical Context

The TLV431BCPKG3 implements a three-terminal adjustable shunt reference architecture with an internal bandgap reference and high-gain NPN-based error amplifier driving a Darlington sink output stage. Its functional modes include closed-loop shunt regulation (with resistive feedback from cathode to reference) and open-loop comparator operation (with reference pin driven externally).

It operates with ≥1.24 V cathode-to-anode headroom and requires ≥55 µA minimum cathode current for regulation across its full industrial temperature range (0°C to 70°C). The device is internally compensated and stable without an output capacitor, though phase margin vs. capacitive load is characterized up to 1 nF for design validation.

Key Specifications

Pinout & Package

TLV431BCPKG3 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 pad not connected internally. Pin 1 is CATHODE (shunt current input), Pin 3 is REF (reference threshold input), and Pin 6 is ANODE (common return, typically grounded).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BCPKG3, TLV431ACPKG3 trades 0.5% accuracy for lower unit cost in commercial-temperature applications, while TLVH431IDBVR extends voltage and current capability at the expense of SC-70 footprint and direct pin compatibility - making TLV431BCPKG3 optimal for space-constrained, precision 1.24–6 V shunt regulation.

Availability

TLV431BCPKG3 is available at Aetrix Electronics and suitable for secondary-side regulation in flyback SMPSs, voltage monitoring in industrial controllers, and comparator-based fault detection in automotive body electronics requiring stable component supply and long-term lifecycle support.

Supply support for TLV431BCPKG3 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 designing analog ICs, embedded processors, and power management solutions for industrial, automotive, and communications markets.

The TLV431 family was developed as a low-voltage, high-accuracy alternative to the TL431 for modern low-power systems - targeting precision shunt regulation, voltage supervision, and integrated-comparator functions in compact 3.3 V and below applications.

FAQ

What is the reference voltage tolerance of TLV431BCPKG3 at 25°C?

The TLV431BCPKG3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal value with a range of 1.234 V to 1.246 V. This tight tolerance is specified for the 'B' grade variant and is confirmed in Section 5.7 of the official TI datasheet SLVS139Z. The TLV431BCPKG3 maintains this accuracy across its commercial temperature range (0°C to 70°C) with ±4 mV total drift.

Can TLV431BCPKG3 replace a standard Zener diode in a 2.5 V regulation circuit?

Yes, TLV431BCPKG3 can directly replace a 2.5 V Zener diode when configured with appropriate external resistors to set V_OUT = 2.5 V. Its 0.25 Ω dynamic impedance, 0.5% initial tolerance, and 80 µA typical cathode current requirement provide significantly better regulation accuracy and thermal stability than typical 5% tolerance Zeners. The SC-70 package also offers superior board-area efficiency compared to DO-35 or SOD-123 Zener packages.

What is the minimum cathode current required for regulation in TLV431BCPKG3?

The TLV431BCPKG3 requires a minimum cathode current of 55 µA to maintain regulation, as specified in Section 5.7 of the TI datasheet for the TLV431B grade across its full operating temperature range (0°C to 70°C). This low I_K(min) enables use in ultra-low-power applications such as battery-backed supervisors or energy-harvesting circuits where current budgets are constrained to sub-100 µA levels.

Is TLV431BCPKG3 stable without an output capacitor?

Yes, TLV431BCPKG3 is internally compensated and stable without an external output capacitor between cathode and anode - a key advantage over many linear regulators. Stability is verified per Figure 5-18 and Figure 5-19 in the datasheet, which characterize phase margin vs. capacitive load up to 1 nF. This eliminates capacitor-related layout complexity and failure modes in isolated feedback paths, especially when used with optocouplers in flyback converters.

What package type does TLV431BCPKG3 use, and how does it compare to SOT-23-3?

TLV431BCPKG3 uses the SC-70 (DCK) package, measuring 2.0 mm × 1.5 mm - 40% smaller in footprint than the standard SOT-23-3 package. While both are 3-terminal shunt references, the SC-70 variant has 6 pins (with 3 NC pins), whereas SOT-23-3 has only 3 active pins. The DCK package enables higher board density in space-critical applications like wearable power management and miniaturized AC-DC adapters.