Diodes Incorporated ZR431N8TA

Overview

ZR431N8TA from Diodes Incorporated is a three-terminal adjustable precision shunt regulator in SO8 package, with 2% reference voltage tolerance (2.50 V), 55 ppm/°C temperature coefficient, and 100 mA cathode current capability; used as high-stability voltage reference in feedback loops of switch-mode power supplies and overvoltage protection circuits.

For engineers reviewing the ZR431N8TA datasheet, ZR431N8TA pinout, ZR431N8TA application, or ZR431N8TA equivalent, key selection criteria include programmable output voltage range (2.5–20 V), low dynamic output impedance (0.75 Ω), temperature-compensated reference, cathode current sink capability (50–100 µA min to 100 mA max), and SO8 thermal performance (780 mW at 25°C).

Technical Context

The ZR431N8TA implements a bandgap-referenced error amplifier with internal temperature compensation, enabling stable 2.50 V reference across –40°C to +85°C. Its cathode-anode-regulator terminal architecture supports two-resistor external programming for output voltages up to 20 V.

It operates as a voltage-controlled current sink: reference input (V_ref) compares against a resistor-divided cathode voltage, driving cathode current to maintain regulation. Dynamic output impedance remains ≤0.75 Ω at DC and <1 Ω up to 100 kHz, supporting fast transient response in closed-loop SMPS designs.

Key Specifications

Pinout & Package

SO8 package (suffix N8), surface-mount, 8-pin wide-body outline with exposed thermal pad (pin 4 internally floating or connected to pin 2 per datasheet). Pin 1 = Cathode, Pin 2 = Anode, Pin 3 = Reference (V_ref), Pins 4–8 = NC or thermal pad tie (see Diodes Inc. DS4-195).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDR, ZR431N8TA trades 5 ppm/°C higher tempco for broader availability and lower unit cost; versus KIA431AP, it delivers 45 ppm/°C better thermal stability-critical for automotive under-hood temperature cycling.

Availability

ZR431N8TA is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, and precision voltage monitoring applications requiring stable component supply and SO8 thermal performance.

Supply support for ZR431N8TA 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

Diodes Incorporated is a global semiconductor company specializing in discrete, analog, and mixed-signal ICs for power management, signal integrity, and connectivity.

ZR431 belongs to Diodes' precision reference product line, designed specifically for high-stability shunt regulation in cost-sensitive, thermally constrained power systems.

FAQ

What is the minimum cathode current required for regulation in ZR431N8TA?

The ZR431N8TA requires a minimum cathode current of 35 µA to maintain regulation at V_Z = V_ref, per Figure 1 in the datasheet. This value increases slightly at temperature extremes but remains ≤50 µA across –40°C to +85°C, enabling use in ultra-low-quiescent current bias networks.

Can ZR431N8TA replace a standard zener diode directly?

Yes-ZR431N8TA replaces standard zeners in 2.5–20 V applications with superior performance: 2% initial tolerance vs. 5–10% for general-purpose zeners, 55 ppm/°C tempco vs. 100–500 ppm/°C, and active regulation vs. passive breakdown. External resistor divider is mandatory; no direct drop-in replacement without circuit modification.

How does the SO8 package improve thermal performance over SOT23?

The SO8 package provides 780 mW power dissipation at 25°C ambient, more than double the 330 mW of SOT23. Its larger copper area and optional thermal pad connection reduce junction-to-ambient thermal resistance by ~40%, allowing sustained 100 mA cathode current without derating in compact layouts.

Is ZR431N8TA compatible with TL431-based PCB footprints?

No-ZR431N8TA uses an SO8 pinout (cathode/anode/V_ref/thermal pad), while TL431ACDR in SO8 has identical pin 1–3 assignment but differs in pin 4 function (NC vs. thermal pad tie). Mechanical compatibility exists, but thermal pad routing and grounding must be verified per Diodes Inc. layout guidelines to avoid instability.