Diodes Incorporated ZR2431F02TA

Overview

ZR2431F02TA from Zetex Semiconductors (now Diodes Incorporated) is a three-terminal adjustable precision shunt regulator in SOT23 package, functioning as a programmable 1.24 V reference with ±2.5% initial tolerance and 52 ppm/°C max temperature coefficient. It sinks 100 µA to 25 mA cathode current, supports output voltage programming from 1.24 V to 15 V via external resistors, and is used in feedback loops of 3.3 V/3 V switch-mode power supplies.

For engineers reviewing the ZR2431F02TA datasheet, ZR2431F02TA pinout, ZR2431F02TA application, or ZR2431F02TA equivalent, key selection factors include its adjustable reference architecture, low dynamic impedance (0.25–2 Ω), temperature-compensated Vref stability, cathode current regulation range, and SOT23 footprint compatibility with space-constrained SMPS designs.

Technical Context

The ZR2431F02TA 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 two-resistor feedback configuration allows precise output voltage setting while maintaining low output noise and high AC rejection.

It operates as a voltage-controlled current sink: cathode voltage (VZ) is regulated relative to the reference terminal (VREF), with GND as the third terminal. Dynamic impedance is specified at 0.25–2 Ω under 10 mA load, and minimum cathode current for regulation is 30–100 µA depending on capacitance conditions.

Key Specifications

Pinout & Package

Package: SOT23 (3-pin, surface-mount, JEDEC TO-236AB). Pin 1 = Cathode (VZ), Pin 2 = Anode (GND), Pin 3 = Reference (VREF).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR and AS431ASTU, ZR2431F02TA offers identical SOT23-3 footprint and lower minimum cathode current (30 µA vs 100 µA), making it better suited for ultra-low-power monitoring, while trading off max current headroom and tighter tolerance options.

Availability

ZR2431F02TA is available at Aetrix Electronics and suitable for switch-mode power supplies, over/under-voltage protection circuits, programmable series regulators, and precision voltage monitors requiring stable component supply and long-term obsolescence management.

Supply support for ZR2431F02TA 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 design house acquired by Diodes Incorporated in 2008; known for high-performance bipolar and precision analog products.

The ZR2431 series belongs to Zetex's precision shunt regulator product line, designed specifically for replacing zener diodes in feedback, protection, and reference applications demanding superior temperature stability and programmability.

FAQ

What is the minimum cathode current required for regulation in ZR2431F02TA?

The minimum cathode current is 30 µA at −40°C to +85°C with no added cathode-anode capacitance. If >100 pF capacitance is present between cathode and anode, minimum cathode current increases to 0.2 mA to ensure stable regulation per datasheet footnote †.

Can ZR2431F02TA replace a standard 3.3 V zener diode directly?

No - it cannot replace a zener directly without external resistors. ZR2431F02TA is a 3-terminal adjustable shunt regulator requiring two external resistors to set output voltage. A direct zener replacement would require fixed-voltage variants like TL431 or dedicated 3.3 V shunt references.

What is the maximum power dissipation for ZR2431F02TA in SOT23 package?

At 25°C ambient, maximum power dissipation is 330 mW. Derating begins above 25°C at 4.4 mW/°C, reaching zero dissipation at 100°C ambient per the SO8/TO92 derating curve applied to SOT23 thermal resistance (θ_JA ≈ 227°C/W).

Does ZR2431F02TA require an output capacitor for stability?

Stability depends on circuit configuration. The datasheet shows instability regions for load capacitance >10 nF in shunt mode. For stable operation, keep cathode-to-ground capacitance ≤10 nF or add series resistance per Figure 4-156 stability boundary curves; 100 pF–1 nF is typically safe without compensation.