Nexperia USA Inc. BZT52H-A39X

Overview

BZT52H-A39X from Nexperia is a precision Zener voltage regulator diode in SOD123F package, designed for low-power voltage reference and overvoltage protection in space-constrained PCBs. It delivers 39 V nominal Zener voltage at 2 mA test current, ±1 % tolerance, 300 Ω max differential resistance, 75 μA max reverse leakage at 31.2 V, and operates up to 150 °C junction temperature - used in power supply feedback loops and analog sensor biasing.

For engineers reviewing the BZT52H-A39X datasheet, BZT52H-A39X pinout, BZT52H-A39X application, or BZT52H-A39X equivalent, this page provides verified electrical specs, thermal behavior, SOD123F mounting guidance, and real-world use cases for stable 39 V regulation in industrial control and automotive non-safety subsystems.

Technical Context

This Zener diode operates in reverse breakdown mode with tightly controlled V_Z = 38.61–39.39 V at I_Z = 2 mA, exhibiting a positive temperature coefficient of +0.05 mV/K across its operating range. Its low 300 Ω dynamic impedance ensures minimal output voltage variation under load transients.

The device uses planar epitaxial construction for stable long-term performance and low noise, with thermal resistance R_th(j-a) = 330 K/W (free air) and R_th(j-sp) = 70 K/W (cathode solder point), enabling reliable operation on FR4 PCBs with standard 1 cm² cathode pad.

Key Specifications

Pinout & Package

SOD123F is a surface-mount plastic package with two gull-wing leads, 1.2 mm lead width, 0.55 mm lead pitch, and 3.6 mm × 1.2 mm body dimensions. The cathode is marked by a bar on the top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZT52H-A39X, the BZT52H-B39 trades 1 % accuracy for lower unit cost while maintaining identical thermal and surge performance, whereas BZX84-C39 sacrifices precision, power rating, and thermal efficiency to fit legacy SOT-23 layouts - making the A39X optimal for new designs demanding accuracy and reliability in minimal area.

Availability

BZT52H-A39X is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical instrumentation requiring stable component supply with guaranteed long-term sourcing and RoHS-compliant packaging.

Supply support for BZT52H-A39X 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete and logic devices, headquartered in Nijmegen, Netherlands, with manufacturing in Asia and Europe.

The BZT52H series belongs to Nexperia's general-purpose Zener diode product line, engineered specifically for precision voltage regulation and clamping in cost-sensitive, space-constrained consumer and industrial applications.

FAQ

What is the maximum continuous Zener current for BZT52H-A39X at 70 °C ambient?

At T_amb = 70 °C, derating applies per the 830 mW rating at 25 °C and thermal resistance of 330 K/W. Maximum continuous power is 830 mW × (1 − (70 − 25)/330) ≈ 705 mW, yielding I_Z(max) = 705 mW / 39 V ≈ 18.1 mA. This assumes adequate PCB copper area for heat dissipation.

Can BZT52H-A39X replace a 39 V TL431 in shunt regulator configurations?

No - the BZT52H-A39X is a passive two-terminal Zener diode and cannot replicate the active feedback, adjustable output, or current-sinking capability of the TL431. It functions only as a fixed-voltage clamp or reference, not as an error amplifier-based regulator.

Is the SOD123F package compatible with standard reflow profiles for lead-free soldering?

Yes - Nexperia specifies reflow soldering as the only recommended method, with peak temperature up to 260 °C for ≤30 seconds. The SOD123F outline complies with IPC-7351B and supports JEDEC J-STD-020D moisture sensitivity level 1 (unlimited floor life).

How does the +0.05 mV/K temperature coefficient affect regulation accuracy over −40 °C to +125 °C?

Over this 165 K range, total V_Z drift is 165 K × 0.05 mV/K = ±8.25 mV, or ±0.021 % of 39 V. Combined with ±1 % initial tolerance, worst-case total variation remains within ±1.021 % - sufficient for most industrial sensing and power control applications.