Texas Instruments TL431AIDCKTG4

Overview

TL431AIDCKTG4 from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, delivering 2.495 V nominal reference voltage with ±1% initial tolerance at 25°C, 0.2 Ω typical dynamic impedance, and sink-current capability from 1 mA to 100 mA. It operates across −40°C to 85°C and serves as a stable feedback element in isolated DC-DC converters and AC/DC power supplies.

For engineers reviewing the TL431AIDCKTG4 datasheet, TL431AIDCKTG4 pinout, TL431AIDCKTG4 application, or TL431AIDCKTG4 equivalent, key selection criteria include temperature drift (≤14 mV over full range), cathode voltage range (2.5 V to 36 V), low output noise, and compatibility with standard two-resistor feedback networks in SMPS designs.

Technical Context

The TL431AIDCKTG4 implements an internal bandgap reference, error amplifier, and NPN output transistor in a three-terminal shunt topology. Its REF pin senses voltage relative to ANODE, triggering cathode current modulation to maintain regulation - enabling precise closed-loop control without external op-amps.

It features sharp turn-on characteristics and stable operation up to 100 mA sink current, with thermal stability validated across industrial temperature range (−40°C to 85°C). The SOT-23-3 package supports high-density PCB layouts while maintaining adequate thermal dissipation (R_θJA = 206°C/W).

Key Specifications

Pinout & Package

SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431AIDCKTG4, TL431ACDBVR trades temperature range for tighter 0.5% tolerance, while TL431BIDBVR delivers both 0.5% tolerance and identical −40°C to 85°C operation - making it a direct upgrade path where enhanced reference stability is critical.

Availability

TL431AIDCKTG4 is available at Aetrix Electronics and suitable for industrial AC/DC converters, isolated flyback power supplies, and servo drive auxiliary rails requiring stable component supply and long-term manufacturability.

Supply support for TL431AIDCKTG4 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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in precision reference and power control ICs.

The TL431 product line was designed specifically for high-accuracy, low-cost voltage regulation in switching power supplies - emphasizing thermal stability, wide output adjustability, and robustness in noisy industrial environments.

FAQ

What is the reference voltage tolerance of TL431AIDCKTG4 at 25°C?

The TL431AIDCKTG4 has a reference voltage tolerance of ±1% at 25°C, corresponding to a nominal 2.495 V output with minimum 2.470 V and maximum 2.520 V. This A-grade specification balances cost and precision for industrial power applications where tighter tolerances are not required.

Can TL431AIDCKTG4 replace a Zener diode in feedback circuits?

Yes, TL431AIDCKTG4 replaces discrete Zener diodes in feedback networks due to its sharp turn-on characteristic, 0.2 Ω dynamic impedance, and adjustable 2.5 V–36 V output. Unlike Zeners, it provides stable regulation across temperature and current - especially critical in isolated SMPS topologies using optocouplers.

What is the maximum cathode voltage rating for TL431AIDCKTG4?

The absolute maximum cathode voltage (V_KA) for TL431AIDCKTG4 is 37 V, with recommended operation up to 36 V. Exceeding this risks permanent damage; design margins should maintain ≤33 V in continuous operation to ensure reliability and thermal safety.

Does TL431AIDCKTG4 require external capacitors for stability?

TL431AIDCKTG4 can oscillate with certain load capacitances and cathode currents - stability boundaries are defined in TI's datasheet Figure 6-18. A 1 nF ceramic capacitor from REF to ANODE is commonly used to suppress high-frequency peaking without compromising transient response.

How does the SOT-23-3 package affect thermal performance of TL431AIDCKTG4?

The SOT-23-3 package has R_θJA = 206°C/W, limiting continuous power dissipation to ~300 mW at 85°C ambient. For >50 mA cathode current applications, copper pour under the ANODE pad and short traces reduce thermal resistance and prevent junction overheating.