Renesas HZ9HA1

Overview

HZ9HA1 from Renesas Electronics is a silicon planar Zener diode designed for precision voltage regulation in low-power stabilized power supplies. It delivers a nominal zener voltage of 9.3–9.7 V at 5 mA, with dynamic resistance of 5.0 Ω, maximum power dissipation of 500 mW, and operates within a junction temperature range up to 175°C. It is commonly used in reference voltage generation for analog sensor interfaces and microcontroller reset circuits.

For engineers reviewing the HZ9HA1 datasheet, HZ9HA1 pinout, HZ9HA1 application, or HZ9HA1 equivalent, key selection criteria include its tight zener voltage tolerance (±0.2 V), low dynamic impedance, DO-35 glass package compatibility with through-hole PCB assembly, and suitability for industrial-grade voltage reference and overvoltage clamping in 5–12 V rail monitoring.

Technical Context

The HZ9HA1 operates as a two-terminal, passive voltage reference device relying on controlled reverse-biased avalanche breakdown. Its zener voltage is specified at I_Z = 5 mA with test condition V_R = 0.5 V for leakage verification, and it exhibits a positive temperature coefficient of approximately +5.0 mV/°C near 9.5 V, as confirmed by Figure 2 in the datasheet.

This device belongs to the HZ(H) Series, which uses silicon planar construction for stable, repeatable breakdown characteristics. It is not intended for high-current shunt regulation but optimized for low-leakage (<25 µA), low-noise reference applications where thermal stability and long-term voltage drift are critical design factors.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode band marking; leads are tinned copper alloy, suitable for wave or hand soldering. Body diameter: 1.8–2.0 mm; overall length: 4.0–4.5 mm; lead spacing: 2.5 mm nominal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4739A and BZX55C9V1, the HZ9HA1 offers superior voltage accuracy (±0.2 V vs. ±5%), lower dynamic impedance (5.0 Ω vs. ≥8 Ω), and verified 175°C junction capability-making it preferred for industrial-grade reference stability where layout space and thermal margin are constrained.

Availability

HZ9HA1 is available at Aetrix Electronics and suitable for industrial sensor references, microcontroller reset circuits, overvoltage clamps, and linear regulator feedback networks requiring stable component supply and traceable sourcing.

Supply support for HZ9HA1 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 to provide high-stability, low-drift voltage references for industrial power supply feedback, sensor excitation, and protection circuits-emphasizing reliability under extended temperature and long-term bias stress.

FAQ

What is the exact zener voltage range specified for HZ9HA1 at 5 mA test current?

The HZ9HA1 has a guaranteed zener voltage range of 9.3 V to 9.7 V when tested at I_Z = 5 mA and T_a = 25°C, per the Electrical Characteristics table on page 3 of Renesas document REJ03G0181-0200 Rev.2.00. This ±0.2 V tolerance is tighter than standard 5% Zener diodes and supports precision reference applications without trimming.

Does HZ9HA1 support operation at elevated ambient temperatures, and what derating applies?

Yes, HZ9HA1 supports ambient temperatures up to 150°C with appropriate power derating. Per Figure 3, its 500 mW rating linearly derates to zero at 175°C junction temperature. At 100°C ambient, maximum allowable power drops to ~350 mW, corresponding to ~37 mA continuous zener current at 9.5 V-enabling use in thermally demanding industrial enclosures.

Is HZ9HA1 RoHS compliant and lead-free?

Yes, HZ9HA1 is RoHS compliant and lead-free. Renesas confirms environmental compliance in accordance with EU Directive 2011/65/EU (RoHS 2), as stated in Note 10 of the datasheet and verified via Renesas' official product environmental reports. The DO-35 package uses lead-free tinning and halogen-free molding compounds.

Can HZ9HA1 be used in place of HZ9HB2, and what is the key difference?

No, HZ9HA1 and HZ9HB2 are not interchangeable without circuit review. While both share the same nominal 9.5 V zener voltage, HZ9HA1 is Grade A (9.3–9.7 V), whereas HZ9HB2 is Grade B (9.5–9.9 V). Their V_Z ranges do not fully overlap, and HZ9HB2 has higher dynamic resistance (20 Ω vs. 5.0 Ω). Substitution may cause feedback loop instability or reference inaccuracy in precision designs.

What is the maximum reverse leakage current for HZ9HA1, and under what condition is it measured?

The maximum reverse leakage current for HZ9HA1 is 25 µA, measured at V_R = 0.5 V and T_a = 25°C, as specified in the Electrical Characteristics table. This low leakage enables high-impedance bias networks-for example, supporting 1 MΩ pull-up resistors in reset circuits while maintaining reliable turn-on thresholds across temperature.