STMicroelectronics TS3431IZ

Overview

TS3431IZ from STMicroelectronics is a programmable shunt voltage reference in TO-92 package, providing adjustable output voltage from 1.24 V to 24 V with ±0.25% initial accuracy (C-grade), 100 ppm/°C temperature coefficient, and sink current capability up to 100 mA across -40°C to +125°C. It replaces TL431 in precision feedback loops for switch-mode power supplies and battery chargers.

For engineers reviewing the TS3431IZ datasheet, TS3431IZ pinout, TS3431IZ application, or TS3431IZ equivalent, this device supports design of stable, space-constrained voltage regulation circuits requiring tight tolerance over industrial temperature range and low dynamic impedance (0.2–0.4 Ω).

Technical Context

The TS3431IZ operates as a two-terminal shunt regulator with cathode-anode configuration, where output voltage is set externally via resistor divider between cathode and reference pin. Its internal bandgap reference ensures stable 1.24 V nominal reference input voltage with minimal drift.

It functions within cathode current range 0.5–100 mA and cathode-to-anode voltage range 1.24–24 V. Key performance includes 100 nV/√Hz wideband noise (1–100 kHz), 21 mV max reference voltage variation over full -40°C to +125°C range, and off-state cathode current as low as 35 nA at 25°C.

Key Specifications

Pinout & Package

TS3431IZ uses TO-92 plastic package (3-pin, through-hole), with standardized pinout: Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Reference (adjust). This configuration enables direct integration into legacy TL431-based designs with identical footprint compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACZ and MAX6008AEUR+T, TS3431IZ uniquely combines programmability, industrial temperature rating, and ±0.25% accuracy in through-hole TO-92 - making it optimal for retrofitting legacy designs requiring enhanced thermal robustness without layout change.

Availability

TS3431IZ is available at Aetrix Electronics and suitable for switch-mode power supplies, battery chargers, instrumentation systems, and computer power supplies requiring stable component supply with long-term manufacturability and consistent parametric performance.

Supply support for TS3431IZ 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The TS3431 belongs to ST's precision analog voltage reference product line, engineered specifically for high-accuracy, temperature-stable feedback and supervision in power conversion and measurement systems.

FAQ

What is the minimum cathode current required for regulation at -40°C?

The TS3431IZ requires a minimum cathode current of 0.5 mA across the full -40°C to +125°C range, as guaranteed in Table 2 of the datasheet. At -40°C, this ensures reliable turn-on and stable reference voltage generation without dropout or oscillation.

Can TS3431IZ replace TL431 in existing designs without modification?

Yes - TS3431IZ shares identical TO-92 pinout (Anode/Cathode/Ref), same electrical interface, and compatible biasing requirements. No PCB or schematic changes are needed; only verify that the existing resistor divider yields the desired output voltage and that thermal dissipation remains within 625 mW limit.

How does the reference input current (I_REF) affect accuracy in high-impedance divider networks?

I_REF is typically 1.5 µA at 25°C and rises to 2 µA over temperature. In divider networks with >100 kΩ total resistance, this current introduces voltage error - e.g., 150 mV drop across 100 kΩ - requiring compensation via lower resistor values or buffered reference inputs.

What is the maximum cathode-to-anode voltage the TS3431IZ can withstand during transient events?

The absolute maximum cathode-to-anode voltage is 25 V, per Table 1. Sustained operation above 24 V risks exceeding safe operating area limits; transient spikes must be clamped below 25 V using external Zener diodes or TVS devices to prevent irreversible damage.