Diodes Incorporated ZR2431Z02TA

Overview

ZR2431Z02TA 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 programmable output voltage from 1.24 V to 15 V via external resistors. It delivers up to 25 mA cathode current, exhibits 52 ppm/°C max temperature coefficient, and operates across –40°C to +85°C for use in feedback loops of DC-DC converters.

For engineers reviewing the ZR2431Z02TA datasheet, ZR2431Z02TA pinout, ZR2431Z02TA application, or ZR2431Z02TA equivalent, this device serves as a high-stability replacement for zener diodes in voltage monitoring, over/under-voltage protection, and low-voltage SMPS feedback circuits where precise, temperature-compensated regulation is required.

Technical Context

The ZR2431Z02TA implements a bandgap-derived 1.24 V reference with internal temperature compensation across –40°C to +85°C, enabling stable operation without external calibration. Its dynamic output impedance is 0.25–2 Ω at 10 mA, and it maintains regulation down to 30 µA minimum cathode current.

It functions as a two-input error amplifier: the reference input (V_REF) compares against a resistor-divided cathode voltage (V_Z), driving an internal NPN transistor to sink current and stabilize the output. The device requires ≥100 pF cathode-to-anode capacitance for stable operation below 0.2 mA cathode current.

Key Specifications

Pinout & Package

SOT89 package (suffix Z), 3-pin surface-mount, exposed thermal pad (pin 2 = cathode, pin 1 = anode, pin 3 = reference). Pin 2 is electrically connected to the tab for enhanced thermal dissipation (1.5 W rating at T_amb = 25°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR and AS431ASTZ, ZR2431Z02TA provides the lowest reference voltage (1.24 V), enabling direct generation of sub-3 V rails without level-shifting, while its SOT89 package delivers superior thermal performance for continuous 25 mA operation in compact industrial power modules.

Availability

ZR2431Z02TA is available at Aetrix Electronics and suitable for switch mode power supplies, voltage monitors, overvoltage protection circuits, and series regulator control requiring stable component supply with guaranteed long-term availability.

Supply support for ZR2431Z02TA 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, now part of Diodes Incorporated, specializes in high-performance analog and discrete semiconductors for power management and signal conditioning.

The ZR2431 product line was designed specifically for precision voltage regulation in space-constrained, thermally demanding DC-DC converter feedback paths and protection circuits-emphasizing low tempco, wide current range, and robust package options.

FAQ

What is the minimum cathode current required for regulation in ZR2431Z02TA?

The minimum cathode current for regulation is 30 µA at 25°C, rising to 100 µA over the full –40°C to +85°C operating range. Below this threshold, the device exits regulation and V_Z collapses. A ≥100 pF cathode-to-anode capacitor is required if operating near this limit to ensure stability.

Can ZR2431Z02TA be used in series regulator configurations?

Yes-ZR2431Z02TA can control external PNP or N-channel MOSFET pass transistors in series configurations. Its low reference input current (≤0.4 µA) minimizes divider error, and its 25 mA cathode sink capability allows direct drive of small-gate MOSFETs or medium-current PNP bases without buffering.

How does the temperature coefficient affect output voltage accuracy?

The maximum temperature coefficient is 52 ppm/°C, meaning total V_REF variation is ≤8 mV over –40°C to +85°C (ΔT = 125°C). This translates to <±0.65% output error in a typical 3.3 V design using R1/R2, making it suitable for industrial-grade power supplies without calibration.

Is ZR2431Z02TA pin-compatible with TL431?

No-ZR2431Z02TA uses Anode–Cathode–Reference pinout (SOT89), while TL431 uses Cathode–Anode–Reference (SO8/SOT23). Direct replacement requires PCB layout revision. Electrical behavior differs too: ZR2431's 1.24 V reference enables lower output voltages without additional resistors, unlike TL431's 2.495 V baseline.