Diodes Incorporated ZR2431N802TA

Overview

ZR2431N802TA from Zetex Semiconductors (now Diodes Incorporated) is a three-terminal adjustable precision shunt regulator IC with 2.5% initial reference voltage tolerance, 52 ppm/°C max temperature coefficient, and 100 µA–25 mA cathode current capability. It functions as a programmable 1.24 V bandgap reference in feedback loops of switch-mode power supplies, enabling accurate 3.3 V or 3 V output regulation via external resistor dividers.

For engineers reviewing the ZR2431N802TA datasheet, ZR2431N802TA pinout, ZR2431N802TA application, or ZR2431N802TA equivalent, key selection criteria include its adjustable shunt regulation architecture, SO8 package thermal performance (780 mW @ 25°C), low dynamic impedance (0.25–2 Ω), and guaranteed operation across –40°C to +85°C ambient.

Technical Context

The ZR2431N802TA implements a temperature-compensated bandgap reference core with internal error amplifier and output stage, configured as a two-input (V_REF, cathode) shunt device. Its reference voltage (1.24 V nominal) is stable over full industrial temperature range and exhibits <8 mV total deviation across –40°C to +85°C.

It operates in active regulation mode when cathode voltage exceeds V_REF by ≥100 µA minimum sink current, with dynamic output impedance defined at 10 mA test condition and scalable via external R1/R2 network per R′ = R_Z(1 + R1/R2). Off-state leakage remains ≤30 µA at 15 V cathode potential.

Key Specifications

Pinout & Package

ZR2431N802TA is supplied in an 8-pin SOIC (SO8) surface-mount package with exposed pad thermal enhancement. Pin 1 is V_REF, pins 2–3 are GND, pins 4–5 are cathode (parallel-connected), pins 6–7 are NC (no internal connection), and pin 8 is anode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDR and KA431AZTA, ZR2431N802TA offers superior thermal performance in SO8 (780 mW vs. 360 mW), lower reference current (0.11 µA typ vs. 2 µA), and optimized 1.24 V reference for sub-3.3 V SMPS designs - making it preferred for space-constrained, thermally demanding industrial power rails.

Availability

ZR2431N802TA is available at Aetrix Electronics and suitable for switch-mode power supplies, voltage monitoring systems, overvoltage protection circuits, and programmable series regulators requiring stable component supply and guaranteed long-term availability.

Supply support for ZR2431N802TA 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, specializing in high-performance discrete and linear products for power management and signal conditioning.

ZR2431 belongs to Zetex's precision shunt regulator product line, engineered specifically for high-stability feedback control in DC-DC converters and voltage supervision circuits where zener diode limitations-such as poor tempco and tolerance-must be overcome.

FAQ

What is the minimum cathode current required for regulation in ZR2431N802TA?

The minimum cathode current for stable regulation is 30 µA at 25°C and increases to 100 µA across the full –40°C to +85°C temperature range. This value is specified under test conditions with V_Z = V_REF and accounts for process variation and thermal drift. Operation below this threshold risks reference voltage collapse and loss of regulation.

Can ZR2431N802TA replace a standard 3.3 V zener diode directly?

No direct replacement is possible without external resistors. ZR2431N802TA requires two external resistors to set output voltage; for 3.3 V, use R1 = 16.2 kΩ and R2 = 10 kΩ (V_OUT = V_REF × (1 + R1/R2)). Unlike a zener, it draws only 0.11 µA reference current, reducing divider power loss by >99% versus typical zener bias networks.

Does ZR2431N802TA require an output capacitor for stability?

Stability depends on circuit configuration: no capacitor needed in basic shunt mode, but ≥100 pF is required between cathode and anode when minimum cathode current falls below 0.2 mA. In series regulator or comparator applications, 1 µF ceramic at the cathode improves transient response and suppresses high-frequency oscillation per Figure 1 test circuit.

How does the SO8 package of ZR2431N802TA improve thermal performance over SOT23?

The SO8 package delivers 780 mW power dissipation at 25°C ambient versus 330 mW for SOT23 - more than doubling thermal headroom. Its larger copper area and dual GND pins reduce junction-to-ambient thermal resistance (θ_JA) by ~40%, enabling reliable 25 mA continuous sink operation in compact industrial PCB layouts without forced airflow or heatsinking.