Diodes Incorporated ZR431CL

Overview

ZR431 from Diodes Incorporated is an adjustable precision shunt regulator in SOT23 or SOT223 packages, functioning as a programmable 2.5 V reference with ±0.5% initial tolerance, 72 ppm/°C max temperature coefficient, and 50 µA–100 mA cathode current capability. It replaces discrete Zener diodes in voltage monitoring, overvoltage protection, and switch-mode power supply feedback loops.

For engineers reviewing the ZR431 datasheet, ZR431 pinout, ZR431 application, or ZR431 equivalent, this page delivers verified package mapping (SOT23/SOT223), confirmed pin functions (Cathode, Anode, Reference), real-world regulation stability data (≤30 mV V_REF drift over –40°C to +125°C), and validated alternative part comparisons for precision analog design.

Technical Context

The ZR431 operates as a two-terminal shunt regulator with a three-terminal interface: Cathode sinks current to set output voltage via external resistor divider; Reference pin senses the 2.5 V internal bandgap; Anode connects to ground. Its architecture provides inherent temperature compensation across –40°C to +125°C operating range.

Dynamic output impedance is ≤0.75 Ω at V_Z = V_REF, enabling stable regulation under fast load transients. The device maintains <0.1 µA off-state cathode current at V_Z = 20 V and exhibits low output noise-critical for high-accuracy feedback paths in isolated DC-DC converters and voltage supervisors.

Key Specifications

Pinout & Package

Available in SOT23 (3-pin, 2.9 mm × 1.3 mm) and SOT223 (4-pin, 6.5 mm × 3.5 mm) surface-mount packages. Pin 4 of SOT223 is internally floating or may be tied to Pin 2 (Anode) per layout requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431BIDBZR and AS431ASTU, the ZR431 offers balanced performance: lower tempco than TL431 (72 vs. 92 ppm/°C) and better thermal robustness than AS431 in compact layouts, making it optimal for cost-sensitive industrial power supplies requiring <30 mV regulation drift.

Availability

ZR431 is available at Aetrix Electronics and suitable for switch-mode power supply feedback, voltage supervision, programmable series regulation, and comparator threshold referencing requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for ZR431 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 manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in certified ISO/TS 16949 and IATF 16949 facilities.

The ZR431 belongs to Diodes' precision reference regulator product line, engineered for high-accuracy voltage control in industrial power management, automotive subsystems, and communications infrastructure where reliability and parametric consistency are critical.

FAQ

What is the minimum cathode current required for regulation in the ZR431?

The ZR431 requires a minimum cathode current (I_Z(MIN)) of 35–50 µA to maintain regulation at V_REF. This value is specified at V_Z = V_REF and ensures stable operation even in ultra-low-power bias networks. Below this threshold, the device exits regulation and V_Z drops nonlinearly.

Can the ZR431 replace a standard Zener diode directly in existing designs?

Yes-the ZR431 can directly replace Zener diodes rated between 2.5 V and 20 V when used with two external resistors to set the output voltage. Its superior temperature stability (72 ppm/°C vs. typical Zener's >1000 ppm/°C), lower dynamic impedance (≤0.75 Ω vs. >10 Ω), and tighter initial tolerance (±0.5%) improve regulation accuracy without board redesign.

How does the ZR431's reference input current affect resistor-divider design?

The ZR431's reference input current (I_REF) is only 0.12–1.0 µA, allowing use of high-value resistor dividers (e.g., 100 kΩ–1 MΩ). This minimizes power loss and reduces sensitivity to resistor tolerance-enabling ±1% overall output accuracy with standard 1% resistors, unlike higher-I_REF references that demand tighter tolerance or lower resistance values.

Is the SOT223 variant of ZR431 still in production?

No-the ZR431GTA (SOT223) is marked End-of-Life (EOL) per Diodes' ordering information. Only SOT23 variants-including ZR431F005TA (±0.5%), ZR431F01TA (±1.0%), and ZR431FTA (±2.0%)-are currently in active production and supported for new designs.