Nexperia USA Inc. BZT52H-A56-QX

Overview

BZT52H-A56-QX from Nexperia is a 56 V ±1 % tolerance Zener diode in SOD123F package, rated for 830 mW total power dissipation at 25 °C ambient, with 375 Ω typical differential resistance at I_Z = 2 mA and <0.3 A non-repetitive peak reverse current - used for precision voltage reference and overvoltage clamping in automotive power rail monitoring circuits.

For engineers reviewing the BZT52H-A56-QX datasheet, BZT52H-A56-QX pinout, BZT52H-A56-QX application, or BZT52H-A56-QX equivalent, key selection criteria include Zener voltage tolerance (±1 %), thermal resistance (150 K/W junction-to-solder-point), AEC-Q101 qualification, reverse leakage (<120 μA at 0.5×V_Z), and SOD123F footprint compatibility with high-density PCB layouts.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable voltage regulation across varying load and temperature conditions. Its ±1 % tolerance and low temperature coefficient (±0.05 mV/K) enable tight reference stability in feedback loops of DC-DC converters and sensor biasing networks.

The device features two terminals (anode and cathode), with cathode identified by a marking bar on the SOD123F body. It supports continuous reverse current up to 250 mA and withstands non-repetitive surge currents up to 0.3 A under 100 μs pulses at 25 °C ambient.

Key Specifications

Pinout & Package

SOD123F surface-mount plastic package: 3.4–3.6 mm length, 2.5–2.7 mm width, 1.0–1.2 mm height, with gull-wing leads and cathode-marked side.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZT52H-A56-QX, the STMicro part trades precision and power for cost and footprint flexibility, while the Vishay part sacrifices automotive reliability and thermal capability - making the Nexperia device uniquely suited for safety-critical, high-temperature, and high-accuracy automotive voltage regulation.

Availability

BZT52H-A56-QX is available at Aetrix Electronics and suitable for automotive power management, engine control unit (ECU) reference design, and ADAS camera surge protection requiring stable component supply with guaranteed long-term availability.

Supply support for BZT52H-A56-QX 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, with leadership in automotive-qualified components and advanced packaging.

The BZT52H-Q series belongs to Nexperia's automotive Zener diode product line, engineered specifically for voltage regulation and transient suppression in harsh-environment vehicle systems including powertrain, chassis, and infotainment domains.

FAQ

What is the maximum continuous reverse current for BZT52H-A56-QX at 85 °C ambient?

At 85 °C ambient, the maximum continuous reverse current is derated to approximately 145 mA based on the 830 mW P_tot rating and thermal resistance of 150 K/W from junction to solder point. This ensures junction temperature remains below 150 °C under steady-state operation on a standard FR4 PCB with 1 cm² cathode pad.

Does BZT52H-A56-QX require external series resistance in shunt regulator configurations?

Yes - a series resistor must be selected to limit current through the diode to stay within its 250 mA absolute maximum forward current and 830 mW power dissipation limits. For a 60 V input regulating to 56 V, a minimum 16 Ω resistor is required to keep power below 830 mW at full load, calculated using (V_in − V_Z)² / P_tot.

How does the ±1 % tolerance affect circuit accuracy in a voltage monitor application?

In a comparator-based overvoltage detector set to trigger at 56 V, the ±1 % tolerance means the actual trip point will fall between 55.44 V and 56.56 V. This 1.12 V window defines the worst-case detection uncertainty and must be accounted for in system-level fault response timing and hysteresis design to avoid nuisance trips or delayed shutdown.

Can BZT52H-A56-QX replace older BZT52C56 variants in existing designs?

Yes - BZT52H-A56-QX is a direct drop-in replacement for BZT52C56 in SOD123F footprints, offering improved ±1 % tolerance (vs. ±5 %), AEC-Q101 qualification, and higher 830 mW power rating (vs. 500 mW). No layout or schematic changes are needed, but system-level validation of tighter voltage tolerance is recommended.