NXP Semiconductors BZB84-B56,215

Overview

BZB84-B56 from Nexperia is a dual common-anode Zener diode in SOT23 package, designed for precision voltage regulation and overvoltage protection in compact DC power rails. It delivers nominal 56 V Zener voltage (54.9–57.1 V), ±2 % tolerance, 425 Ω typical differential resistance at 2 mA, 0.05 µA reverse current at 45 V, and AEC-Q101 qualification for automotive use.

For engineers reviewing the BZB84-B56 datasheet, BZB84-B56 pinout, BZB84-B56 application, or BZB84-B56 equivalent, this page provides verified pin functions, thermal derating guidance, dual-diode configuration implications, and validated automotive-grade alternatives - all grounded in Nexperia's 2009 product data sheet Rev. 03.

Technical Context

This dual Zener operates with shared anode (Pin 3) and independent cathodes (Pins 1 and 2), enabling bidirectional clamping or dual-rail regulation without external node coupling. Its 150 °C max junction temperature and FR4 PCB thermal resistance of 417 K/W (junction-to-ambient) define its safe operating area under pulsed surge conditions.

The device supports non-repetitive peak reverse power dissipation up to 40 W (100 µs square wave, T_j = 25 °C), with total continuous power limited to 300 mW at T_amb ≤ 25 °C. Its −2.0 to +2.5 mV/K temperature coefficient at 56 V ensures stable regulation across industrial temperature ranges.

Key Specifications

Pinout & Package

Package: SOT23 (TO-236AB), 3-lead surface-mount plastic package with 1.9 mm × 1.1 mm footprint and 0.9 mm height - optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZB84-B56, BZB84-C56 trades precision for cost while retaining identical surge capability and package, whereas MMBZ5256BS sacrifices dual functionality, automotive qualification, and power rating - making BZB84-B56 the sole option for AEC-Q101-compliant dual-rail 56 V regulation.

Availability

BZB84-B56 is available at Aetrix Electronics and suitable for automotive ECUs, industrial sensor signal conditioning, telecom DC-DC feedback networks, and medical equipment overvoltage protection requiring stable component supply and long-term lifecycle assurance.

Supply support for BZB84-B56 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 logic, discrete, and MOSFET solutions, with leadership in automotive-qualified components.

The BZB84 series belongs to Nexperia's general-purpose Zener portfolio, engineered specifically for space-constrained, AEC-Q101-compliant voltage regulation and transient suppression in automotive and industrial power systems.

FAQ

What is the maximum continuous forward current for BZB84-B56?

The absolute maximum forward current is 200 mA per diode, as specified in Table 5 of the Nexperia datasheet Rev. 03. This rating applies under steady-state conditions with ambient temperature ≤25 °C and assumes proper PCB thermal relief. Exceeding this value risks permanent junction damage due to thermal runaway.

How does the dual common-anode configuration affect circuit layout?

The common anode (Pin 3) must be connected to the reference potential (e.g., ground or bias rail), while Pins 1 and 2 serve independent cathodes. This allows either two separate 56 V clamps sharing one return path or back-to-back connection for bidirectional protection - eliminating need for external node tying and reducing parasitic inductance in surge paths.

Is BZB84-B56 suitable for use in a 48 V automotive battery system?

Yes - its 56 V nominal Zener voltage provides appropriate headroom above 48 V nominal systems, and AEC-Q101 qualification confirms suitability for automotive environments. The 40 W non-repetitive peak power rating handles ISO 7637-2 transients, while the −40 °C to +150 °C operating range covers full automotive temperature extremes.

What is the thermal resistance from junction to solder point (R_th(j-sp)) for this device?

R_th(j-sp) is 100 K/W, measured with soldering points at Pins 1 and 2 on an FR4 PCB with single-sided copper and standard SOT23 footprint (Table 6). This value enables accurate junction temperature estimation during surge events by measuring solder point temperature rise and applying ΔT = P × R_th(j-sp).