STMicroelectronics TL1431ACDT

Overview

TL1431ACDT from STMicroelectronics is an adjustable precision shunt voltage reference IC designed for feedback regulation in switching and linear power supplies, error amplifiers, and voltage monitoring circuits. It delivers 2.500 V nominal reference voltage with ±0.25% initial accuracy, operates over 1–100 mA cathode current, exhibits 0.22 Ω typical dynamic impedance, and supports automotive-grade temperature range (−40 °C to +125 °C) in SO-8 package.

For engineers reviewing the TL1431ACDT datasheet, TL1431ACDT pinout, TL1431ACDT application, or TL1431ACDT equivalent, this page provides verified electrical specifications, SO-8 terminal mapping, thermal performance data, automotive qualification context, and validated alternative options for precision voltage reference design.

Technical Context

The TL1431ACDT functions as a 2.5 V bandgap-derived shunt reference with internal error amplifier and NPN pass transistor. Its output voltage is set externally via two resistors between cathode, anode, and reference terminals, enabling programmable regulation from 2.5 V to 36 V. The device maintains stable operation across 1–100 mA sink current with guaranteed low dynamic impedance (≤0.5 Ω).

It integrates temperature compensation circuitry achieving ±90 ppm/°C max temperature coefficient and ≤20 mV total reference voltage deviation over −40 °C to +125 °C. The SO-8 batwing package provides enhanced thermal dissipation (R_thJA = 85 °C/W), supporting up to 960 mW power dissipation at 25 °C ambient.

Key Specifications

Pinout & Package

TL1431ACDT is supplied in SO-8 batwing plastic micropackage (ECOPACK® compliant), featuring gull-wing leads optimized for automated assembly and thermal performance. Pin 1 is Cathode, Pin 2 is Anode, Pin 3 is Reference, Pins 4–5 are NC, Pin 6 is Anode (redundant), Pin 7 is Cathode (redundant), Pin 8 is NC - per Figure 2 of ST DocID5286 Rev 9.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL1431ACDT, TL431ACDR trades 0.25% accuracy for broader vendor availability and lower unit cost, while MAX6008AEUR+T offers superior tempco and quiescent current but sacrifices programmability and sink capability - selection depends on whether adjustable output, automotive qualification, or ultra-low power dominates the design priority.

Availability

TL1431ACDT is available at Aetrix Electronics and suitable for automotive power conversion, industrial SMPS feedback loops, and programmable protection circuits requiring stable component supply with AEC-Q100 compliance, long-term lifecycle support, and traceable sourcing.

Supply support for TL1431ACDT 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power ICs, sensors, and analog components for automotive, industrial, and consumer markets.

The TL1431 product line delivers precision shunt references optimized for high-reliability power management in harsh environments, with emphasis on automotive-grade thermal stability, robust ESD performance, and flexible programmability across multiple package options.

FAQ

What is the minimum cathode current required for regulation in TL1431ACDT?

The TL1431ACDT requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 4 of ST DocID5286 Rev 9. Below this threshold, the reference voltage may deviate beyond its guaranteed accuracy band, especially at temperature extremes. This value is confirmed across all operating conditions including −40 °C to +125 °C ambient.

Can TL1431ACDT replace a Zener diode in existing designs?

Yes - TL1431ACDT can directly replace 2.5 V Zener diodes in shunt regulator applications, offering superior initial accuracy (±0.25% vs. ±5%), lower dynamic impedance (0.22 Ω vs. 10–100 Ω), and tighter temperature coefficient (±90 ppm/°C vs. ±1000 ppm/°C). External resistor values must be recalculated using V_OUT = 2.5 × (1 + R1/R2) instead of Zener voltage.

Does TL1431ACDT require external compensation for stability?

No external compensation is required for basic shunt regulator operation. However, Figure 20 in the datasheet shows that capacitive loads >10 nF on the cathode node may cause instability; ST recommends limiting cathode capacitance to <10 nF or adding a 1–10 Ω series resistor if larger bulk capacitance is needed for ripple suppression.

How does the SO-8 batwing package improve thermal performance over TO-92?

The SO-8 batwing package reduces junction-to-ambient thermal resistance to 85 °C/W versus 200 °C/W for TO-92, enabling 960 mW power dissipation at 25 °C ambient - more than 1.5× higher than TO-92's 625 mW rating. This allows higher cathode current operation without derating in compact PCB layouts, critical for space-constrained automotive modules.