Texas Instruments TL431ACDCKTE4

Overview

TL431ACDCKTE4 from Texas Instruments is a precision programmable shunt voltage reference in SC-70 (DCK) package, delivering 2.47–2.52 V reference voltage with ±1% initial tolerance at 25°C, 0.4–0.6 mA minimum cathode current for regulation, and 0.2 Ω typical dynamic impedance-used in secondary-side feedback loops of isolated flyback converters and adjustable linear regulators.

For engineers reviewing the TL431ACDCKTE4 datasheet, TL431ACDCKTE4 pinout, TL431ACDCKTE4 application, or TL431ACDCKTE4 equivalent, this page provides verified pin functions, thermal and electrical specs per TI SLVS543P, real-world use cases in power supply regulation and voltage monitoring, and two validated alternative parts with documented differences.

Technical Context

The TL431ACDCKTE4 implements an internal error amplifier and NPN transistor output stage configured as a three-terminal adjustable shunt regulator. Its reference input (REF) compares against an internal 2.495 V bandgap-derived threshold, controlling cathode-to-anode conduction to maintain setpoint voltage across external resistive dividers.

It operates over −40°C to 85°C (I-grade), supports cathode voltages from V_ref to 36 V, sinks 1–100 mA cathode current, and achieves <6 mV full-temperature drift in SC-70 packaging-enabling stable closed-loop regulation without external compensation in most SMPS feedback designs.

Key Specifications

Pinout & Package

TL431ACDCKTE4 uses the SC-70-6 (DCK) package: 2.2 mm × 1.35 mm body, 0.65 mm pitch, 6-pin configuration with pin 2 and pin 5 internally unconnected (NC). Thermal resistance R_θJA = 259°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDCKTE4, TL431ACDBVR offers identical electrical performance in a smaller 3-pin package but sacrifices NC pins for routing flexibility, while TLVH431ACDBVR trades higher voltage capability for lower reference voltage-making each suitable only for distinct voltage and layout constraints.

Availability

TL431ACDCKTE4 is available at Aetrix Electronics and suitable for industrial power supplies, factory automation controllers, and battery management systems requiring stable component supply with guaranteed long-term continuity.

Supply support for TL431ACDCKTE4 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 TL431 family was designed as a pin-compatible, cost-optimized replacement for discrete Zener-based references-targeting high-volume power supply feedback, voltage monitoring, and programmable regulation in industrial, automotive, and consumer systems.

FAQ

What is the reference voltage tolerance of TL431ACDCKTE4 at 25°C?

The TL431ACDCKTE4 has a ±1% initial reference voltage tolerance at 25°C, corresponding to a V_ref range of 2.47 V to 2.52 V per TI SLVS543P Rev P. This A-grade specification is confirmed in Section 7.8 (Electrical Characteristics, TL431AC) and applies specifically to the DCK package variant. The tolerance remains stable across cathode currents from 1 mA to 100 mA and is independent of anode voltage within recommended operating conditions.

Does TL431ACDCKTE4 support operation at −40°C?

Yes, TL431ACDCKTE4 is rated for operation from −40°C to +85°C (I-grade temperature range), as specified in TI's device nomenclature and Section 7.4 of SLVS543P. Its V_I(dev) is ≤14 mV over this full range, and all electrical characteristics-including V_ref, I_KA(min), and |z_KA|-are guaranteed across this interval. The SC-70 package's thermal metrics (R_θJA = 259°C/W) require appropriate PCB copper area for sustained 100 mA operation at low ambient temperatures.

What are the NC pins on TL431ACDCKTE4 used for?

TL431ACDCKTE4 in the SC-70-6 (DCK) package has three NC pins: Pin 2, Pin 5, and Pin 6. Per TI's Pin Configuration and Functions table (Section 6), these pins have no internal connection and must be left unconnected on the PCB. They serve no electrical function, cannot be used for thermal relief, and do not affect device operation-unlike the ANODE (Pin 4), which must be tied to system ground to establish the reference potential for REF (Pin 3) and CATHODE (Pin 1).

Can TL431ACDCKTE4 replace a standard 5.1 V Zener diode?

Yes, TL431ACDCKTE4 can directly replace a 5.1 V Zener diode in shunt regulation applications by configuring external resistors R1 and R2 to set V_OUT = V_ref(1 + R1/R2). For 5.1 V output, R1/R2 ≈ 1.04. Unlike Zeners, TL431ACDCKTE4 provides ±1% accuracy, <14 mV temperature drift, and 0.2 Ω dynamic impedance-yielding tighter regulation, lower noise, and improved stability across temperature and load. Minimum cathode current remains 0.4–0.6 mA, matching typical Zener knee requirements.

What is the maximum cathode voltage for TL431ACDCKTE4?

The absolute maximum cathode-to-anode voltage (V_KA) for TL431ACDCKTE4 is 37 V, per Section 7.1 Absolute Maximum Ratings in SLVS543P. However, the recommended operating maximum is 36 V (Section 7.4). Operation at 36 V is fully characterized: dynamic impedance remains 0.2–0.5 Ω, off-state cathode current stays ≤0.5 µA, and ΔV_ref/ΔV_KA is −1 to −2 mV/V-ensuring predictable performance in high-voltage industrial rails and telecom power systems.