Diodes Incorporated ZR2431G02TA

Overview

ZR2431G02TA from Zetex Semiconductors (now Diodes Incorporated) is a three-terminal adjustable precision shunt regulator with 2.5% initial reference voltage tolerance, 1.24 V nominal reference voltage, and 52 ppm/°C max temperature coefficient. It sinks 100 µA to 25 mA, operates from –40°C to +85°C, and is packaged in SOT223 with pin 4 floating or tied to pin 2. It serves as a programmable voltage reference in SMPS feedback loops.

For engineers reviewing the ZR2431G02TA datasheet, ZR2431G02TA pinout, ZR2431G02TA application, or ZR2431G02TA equivalent, key selection criteria include reference voltage accuracy, cathode current range, thermal stability, dynamic impedance, and SOT223 package power dissipation (2 W at 25°C).

Technical Context

The ZR2431G02TA implements a bandgap-derived, temperature-compensated reference core with internal error amplifier and output stage optimized for shunt regulation. Its reference voltage (V_REF) is stable across –40°C to +85°C, with deviation ≤8 mV over full temperature range.

It functions as a two-input comparator: cathode voltage (V_Z) and reference input (V_REF) determine conduction state. Dynamic output impedance is 0.25–2 Ω at 10 mA, and circuit-level impedance scales with external resistor ratio per R′ = R_Z(1 + R₁/R₂).

Key Specifications

Pinout & Package

SOT223 package (suffix G), 4-pin outline with pin 4 electrically isolated or internally connected to pin 2 (anode/cathode common). Thermal pad on underside enhances heat transfer.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDR and AS431ASTU, ZR2431G02TA offers higher power handling (2 W in SOT223), broader cathode current range (100 µA–25 mA), and proven robustness in industrial SMPS feedback - making it optimal where thermal margin and wide operating range are critical.

Availability

ZR2431G02TA is available at Aetrix Electronics and suitable for switch mode power supplies, voltage supervision systems, overvoltage protection circuits, and series regulator references requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for ZR2431G02TA 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

Zetex Semiconductors was a UK-based analog IC and discrete semiconductor designer acquired by Diodes Incorporated in 2008; known for high-performance precision references and power management devices.

ZR2431 belongs to Zetex's precision shunt regulator product line, engineered specifically for high-stability, programmable voltage reference applications in power conversion and protection circuits.

FAQ

What is the maximum cathode voltage ZR2431G02TA can withstand?

The absolute maximum cathode voltage is 15 V. Exceeding this risks permanent damage. In normal operation, cathode voltage must remain ≥ V_REF (1.24 V) and ≤15 V. Derating is required above 25°C ambient per the 2 W SOT223 power curve - at 75°C ambient, max usable power drops to ~1.0 W.

Can ZR2431G02TA replace a standard zener diode directly?

Yes, but only in three-terminal configurations where anode, cathode, and reference pins are properly connected. Unlike two-terminal zeners, ZR2431G02TA requires external resistor biasing and cannot be dropped in without modifying the feedback network. Its superior tempco and tighter tolerance justify redesign in performance-critical applications.

How does pin 4 function in the SOT223 package?

In the SOT223 (G suffix) package, pin 4 is not internally connected to any die node. It may be left unconnected or soldered to pin 2 (anode) to improve thermal conduction to the PCB copper pour. Doing so reduces junction-to-ambient thermal resistance by ~10°C/W, supporting higher continuous power dissipation.

What is the minimum cathode current needed to maintain regulation?

The minimum cathode current for guaranteed regulation is 30 µA at 25°C, rising to 100 µA over full temperature range (–40°C to +85°C). Below this, the device exits regulation and V_Z collapses. External resistor values must ensure I_Z ≥100 µA under worst-case conditions including temperature and tolerance stack-up.