Renesas HZ24H1

Overview

HZ24H1 from Renesas Electronics is a silicon planar Zener diode designed for precision voltage regulation in stabilized power supplies, featuring a nominal zener voltage of 24.3–25.5 V at 2 mA test current, 500 mW power dissipation, and low dynamic resistance of 19 Ω, commonly used in overvoltage protection and reference circuits for industrial control modules.

For engineers reviewing the HZ24H1 datasheet, HZ24H1 pinout, HZ24H1 application, or HZ24H1 equivalent, this page delivers verified electrical specs, DO-35 package details, thermal behavior, temperature coefficient data, and real-world substitution guidance - all grounded in Renesas' official REJ03G0181-0200 Rev.2.00 specification.

Technical Context

The HZ24H1 operates as a two-terminal voltage reference device with a tightly controlled zener breakdown region, optimized for DC stabilization under low-to-moderate current conditions (IZ = 2 mA). Its junction temperature rating of 175°C supports operation in thermally demanding environments such as power supply feedback loops and sensor biasing networks.

It exhibits a positive zener voltage temperature coefficient of +0.06 %/°C (typ.) near 24 V, confirmed by Figure 2 in the datasheet, and maintains stable regulation across ambient temperatures up to 100°C before derating begins per Figure 3 - critical for embedded systems requiring consistent reference accuracy without active compensation.

Key Specifications

Pinout & Package

Package: DO-35 glass axial package (Renesas JEITA code GRZZ0002ZB-A), 2.0 mm diameter × 26.0 mm length, 0.13 g mass, cathode band marked in navy blue.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode applications.

Compared with 1N4749A and BZX55-C24, the HZ24H1 offers tighter 24.3–25.5 V tolerance (±2.5%) and lower 19 Ω dynamic resistance in the same DO-35 form factor - delivering superior voltage reference stability for feedback and sensing without PCB redesign.

Availability

HZ24H1 is available at Aetrix Electronics and suitable for industrial power supplies, sensor interface modules, overvoltage protection circuits, and programmable threshold detectors requiring stable component supply and long-term obsolescence management.

Supply support for HZ24H1 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

Renesas Electronics Corporation is a Japanese semiconductor manufacturer specializing in microcontrollers, analog and power devices, and system-on-chip solutions for industrial, automotive, and infrastructure markets.

The HZ(H) Series Zener diodes were developed specifically for high-stability DC voltage regulation in industrial-grade power conversion and signal conditioning applications, emphasizing low leakage, tight tolerance, and thermal robustness.

FAQ

What is the exact zener voltage range specified for HZ24H1 at 2 mA test current?

The HZ24H1 has a guaranteed zener voltage range of 24.3 V minimum to 25.5 V maximum when tested at I_Z = 2 mA, as defined in the "Electrical Characteristics" table on page 4 of Renesas document REJ03G0181-0200 Rev.2.00. This 2.5% tolerance band reflects its Grade 1 specification within the HZ(H) Series and is measured under DC conditions per Note 1.

Does HZ24H1 support operation at elevated ambient temperatures, and how does power dissipation change?

Yes, HZ24H1 supports ambient temperatures up to 100°C before linear derating begins, as shown in Figure 3 ("Power Dissipation vs. Ambient Temperature"). At 25°C, it delivers full 500 mW; at 100°C, rated power drops to approximately 250 mW. Derating follows a straight-line relationship, ensuring predictable thermal performance in sealed industrial enclosures where airflow is limited.

What is the polarity marking and physical orientation for HZ24H1 in circuit assembly?

HZ24H1 uses a navy blue cathode band to identify Pin 1 (cathode), consistent with standard DO-35 diode marking conventions. During PCB assembly, the banded end must connect toward the higher-potential node (e.g., positive rail or feedback node), while the unbanded anode (Pin 2) connects to circuit common or ground - reversing polarity will prevent zener conduction and cause open-circuit behavior.

How does the temperature coefficient of HZ24H1 impact its use in precision reference applications?

HZ24H1 exhibits a typical zener voltage temperature coefficient (γ_Z) of +0.06 %/°C, as confirmed in Figure 2 of the datasheet. Over a −40°C to +85°C range, this results in ~75 mV total drift - acceptable for industrial feedback loops but insufficient for metrology-grade references. For improved stability, pair HZ24H1 with a complementary NTC thermistor network or select a compensated reference IC instead.

Is HZ24H1 RoHS compliant and suitable for lead-free reflow soldering processes?

Yes, HZ24H1 meets EU RoHS Directive requirements as confirmed by Renesas' environmental compliance documentation. Its DO-35 glass package is rated for standard lead-free reflow profiles (peak temperature ≤260°C, 60-second duration), and the device carries no exemptions. Always verify latest compliance status via Renesas' official product page or material declaration reports before high-volume production release.