Diodes Incorporated ZR431LC02L

Overview

ZR431LC02L from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 2.5% initial tolerance, 50ppm/°C max temperature coefficient, and programmable output voltage from 1.24V to 10V via external resistors. It sinks 100μA–25mA cathode current, operates from –40°C to +85°C, and is widely used in the feedback loop of switch-mode power supplies to regulate 3.3V or 3V outputs.

For engineers reviewing the ZR431LC02L datasheet, ZR431LC02L pinout, ZR431LC02L application, or ZR431LC02L equivalent, key selection criteria include reference voltage accuracy, thermal stability, dynamic impedance (≤2Ω), cathode current capability, and SOT23 surface-mount compatibility for compact power control designs.

Technical Context

The ZR431LC02L implements a bandgap-based, temperature-compensated reference core with internal error amplifier and NPN pass transistor. Its regulation relies on external R1/R2 resistor divider to set VOUT = VREF × (1 + R1/R2), where VREF is stabilized at 1.24V ±2.5%.

It functions as a two-node voltage-controlled current sink: cathode voltage determines conduction state, while reference pin monitors the divided output. Dynamic output impedance is reduced by external resistor ratio scaling-e.g., R' = RZ × (1 + R1/R2)-enabling stable regulation under load transients up to 25mA.

Key Specifications

Pinout & Package

Package: SOT23-3, surface-mount, lead-free, RoHS-compliant, footprint per AP02002 (2.9mm × 1.35mm × 1.03mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR and AS431ASTZTR-G1, ZR431LC02L offers superior thermal stability (50 ppm/°C vs. ≥92 ppm/°C) and lower minimum cathode current (30 µA), making it optimal for energy-efficient, wide-temperature industrial power supervision.

Availability

ZR431LC02L is available at Aetrix Electronics and suitable for switch-mode power supplies, voltage monitoring circuits, programmable series regulators, and under-voltage lockout systems requiring stable component supply and long-term manufacturability.

Supply support for ZR431LC02L 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, manufacturing, and distribution operations across Asia, Europe, and North America.

The ZR431L belongs to Diodes' precision voltage reference product line, engineered specifically for high-stability, low-power shunt regulation in cost-sensitive power management and feedback control applications.

FAQ

What is the minimum cathode current required for regulation in ZR431LC02L?

The ZR431LC02L requires a minimum cathode current of 30 µA to maintain regulation, as specified in its Electrical Characteristics table. This value ensures stable operation even under very light loads, such as in high-impedance feedback networks or low-power monitoring circuits where current draw must be minimized.

Can ZR431LC02L replace a standard zener diode directly?

Yes-ZR431LC02L can directly replace zener diodes in most shunt regulation applications, offering superior temperature stability (50 ppm/°C vs. typical 100–500 ppm/°C for zeners), tighter tolerance (2.5%), and programmable output. However, it requires three terminals (cathode, anode, reference), so PCB layout must accommodate the third pin versus two-terminal zeners.

How does the external resistor divider affect output voltage accuracy?

Output voltage accuracy depends on V_REF tolerance (±2.5%), resistor ratio tolerance, and temperature coefficients. Using 1% metal-film resistors with low TCR (<100 ppm/°C) limits total error to ~3.5% over temperature. The reference pin draws only 0.02–0.4 µA, minimizing loading error on the divider.

Is ZR431LC02L suitable for automotive applications?

While ZR431LC02L operates from –40°C to +85°C and meets AEC-Q200 stress test recommendations for passive components, it is not officially AEC-Q100 qualified. For automotive-critical systems, Diodes' AEC-Q100-qualified AS431 variants are recommended; ZR431LC02L is appropriate for non-safety-critical infotainment or body electronics with validated thermal derating.