Diodes Incorporated ZHT431C01L

Overview

ZHT431C01L from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 1% initial reference voltage tolerance (2.50 V), temperature coefficient of ≤67 ppm/°C, and cathode current capability up to 100 mA. It operates across –55°C to +125°C and sets output voltage from 2.5 V to 20 V via external resistor divider. It replaces standard Zener diodes in high-stability voltage monitoring and overvoltage protection circuits.

For engineers reviewing the ZHT431C01L datasheet, ZHT431C01L pinout, ZHT431C01L application, or ZHT431C01L equivalent, key selection criteria include its TO-92 package, programmable regulation threshold, low dynamic impedance (0.75 Ω), and guaranteed operation over extended industrial temperature range.

Technical Context

The ZHT431C01L functions as a two-input, one-output shunt regulator: the reference input (VREF) senses voltage at the cathode (VZ) through an external resistive divider, while the cathode sinks current to maintain regulation. Its internal bandgap reference ensures stable 2.50 V nominal reference voltage independent of load or supply variation.

It uses a temperature-compensated architecture delivering ≤30 mV total reference voltage deviation over –55°C to +125°C and supports open-loop gain >60 dB up to 10 kHz. Dynamic output impedance remains ≤0.75 Ω under 1–100 mA cathode current, enabling tight regulation in feedback loops for SMPS and voltage supervisors.

Key Specifications

Pinout & Package

Package: TO-92 (3-lead plastic through-hole). Pin assignment verified per Diodes Inc. Issue 7 datasheet, Figure 1 and Package Outline page 8.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431CDBZR and KA431AZTA, ZHT431C01L delivers tighter 1% tolerance and superior temperature stability (≤30 mV VDEV) in a legacy-compatible TO-92 through-hole package-ideal for field-replaceable modules and industrial retrofits requiring mechanical robustness and long-term calibration retention.

Availability

ZHT431C01L is available at Aetrix Electronics and suitable for industrial power supervision, embedded voltage monitoring, and overvoltage protection circuits requiring stable component supply and long-lifecycle support.

Supply support for ZHT431C01L 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 and manufacturing operations across Asia and the Americas.

The ZHT431 belongs to Diodes' precision shunt regulator product line, engineered specifically for high-accuracy, wide-temperature-range voltage reference and regulation in industrial, automotive, and telecom infrastructure applications.

FAQ

What is the minimum cathode current required for ZHT431C01L to regulate?

The ZHT431C01L requires a minimum cathode current (IZmin) of 50 mA to maintain regulation at its nominal 2.50 V reference voltage. This value is specified at Tamb = 25°C and applies across the full –55°C to +125°C operating range per the datasheet's Recommended Operating Conditions table. Below this current, regulation becomes unstable and output voltage may deviate beyond tolerance limits.

Can ZHT431C01L be used in place of a standard 5.1 V Zener diode?

Yes, ZHT431C01L can replace a 5.1 V Zener by configuring R1 and R2 to set VZ = 5.1 V (e.g., R1 = 10 kΩ, R2 ≈ 9.8 kΩ). Unlike passive Zeners, it provides 1% initial accuracy, ≤67 ppm/°C tempco, and active regulation-delivering significantly better stability, lower dynamic impedance (0.75 Ω vs. >10 Ω), and predictable turn-on behavior under varying load conditions.

Is ZHT431C01L RoHS-compliant and halogen-free?

Yes, ZHT431C01L uses Diodes Incorporated's "Green" molding compound, explicitly stated as containing no bromine (Br) or antimony (Sb). It complies with RoHS Directive 2011/65/EU and meets JEDEC JS-709B halogen-free requirements, making it suitable for environmentally regulated PCB assemblies and export markets with strict material declarations.

Does ZHT431C01L require an external capacitor for stability in shunt regulator configurations?

No external capacitor is required for basic shunt regulation, but a 0.01 µF ceramic capacitor placed between cathode and anode improves high-frequency noise rejection and transient response. The datasheet's Typical Characteristics show stable pulse response with no oscillation up to 100 mA step loads, confirming inherent stability without added capacitance in most linear applications.