Diodes Incorporated ZR431LF01TA

Overview

ZR431LF01TA from Diodes Incorporated is a 1% tolerance, adjustable precision shunt regulator in SOT23 package, featuring 1.24 V reference voltage, 50 ppm/°C max temperature coefficient, and 100 µA–25 mA cathode current capability. It serves as a programmable voltage reference in feedback loops of switch-mode power supplies, enabling accurate 3.3 V or 3 V output regulation.

For engineers reviewing the ZR431LF01TA datasheet, ZR431LF01TA pinout, ZR431LF01TA application, or ZR431LF01TA equivalent, key selection criteria include reference voltage accuracy, thermal stability over –40°C to +85°C, dynamic output impedance ≤2 Ω, and compatibility with external resistor programming for 1.24–10 V output range.

Technical Context

The ZR431LF01TA implements a bandgap-based, temperature-compensated reference core with internal error amplifier and NPN pass transistor. Its three-terminal architecture allows direct integration into shunt or series regulator topologies without external biasing components.

It operates as a two-input comparator driving an output transistor: the reference input (VREF) compares against a resistor-divided cathode voltage, while the cathode (VZ) sinks current to regulate loop voltage. Output voltage is set by R1/R2 ratio per VOUT = VREF × (1 + R1/R2), with VREF tightly stabilized at 1.24 V ±1%.

Key Specifications

Pinout & Package

Package: SOT23 - surface-mount, 3-pin, lead-free, RoHS-compliant plastic package with 380 °C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431CDBVR and KA431AZTA, ZR431LF01TA delivers tighter 1% reference accuracy and lower 50 ppm/°C tempco-critical for industrial power supplies requiring ±1% output stability across –40°C to +85°C-while maintaining identical SOT23 footprint and pinout.

Availability

ZR431LF01TA is available at Aetrix Electronics and suitable for switch-mode power supplies, voltage monitoring circuits, low-dropout series regulators, and fixed-regulator enhancement applications requiring stable component supply and guaranteed long-term availability.

Supply support for ZR431LF01TA 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, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The ZR431L product line delivers precision shunt regulation with enhanced thermal stability and tight tolerance for feedback control in compact, cost-sensitive power conversion systems.

FAQ

What is the minimum cathode current required for regulation?

The ZR431LF01TA requires 30–100 µA minimum cathode current (I_Z(MIN)) to maintain regulation, verified per Figure 1 in DS33256 Rev. 4–2. This defines the lowest usable current in low-power monitoring or standby modes before regulation collapses.

Can ZR431LF01TA replace a standard zener diode directly?

Yes-it functions as a 3-terminal zener replacement with superior performance: 1% reference accuracy vs. typical 5% zener tolerance, 50 ppm/°C tempco vs. 100–500 ppm/°C for zeners, and programmable voltage via resistors instead of fixed breakdown voltage.

How does the reference input current affect resistor selection?

With I_REF ≤0.4 µA (max), the reference input draws negligible current, allowing high-value resistor dividers (e.g., 100 kΩ/10 kΩ) without loading error. This enables low-power designs and minimizes self-heating effects on accuracy.

Is ZR431LF01TA suitable for automotive applications?

It operates across –40°C to +85°C and meets AEC-Q200 stress test recommendations for passive components, but is not AEC-Q100 qualified. Use in automotive infotainment or body electronics is common; for safety-critical powertrain systems, consult Diodes Incorporated for qualification status.