Nexperia USA Inc. BZX84-A51,215

Overview

BZX84-A51,215 from Nexperia is a ±1 % tolerance Zener voltage regulator diode in SOT23 (TO-236AB) package, designed for precision low-power voltage reference and clamping in space-constrained PCBs. It delivers a nominal 51 V breakdown voltage at 2 mA test current, with 400 Ω maximum differential resistance and 180 μA reverse leakage at 38.8 V, supporting stable regulation in power supply feedback paths and overvoltage protection circuits.

For engineers reviewing the BZX84-A51,215 datasheet, BZX84-A51,215 pinout, BZX84-A51,215 application, or BZX84-A51,215 equivalent, key selection considerations include its ±1 % V_Z tolerance, 250 mW steady-state power rating, non-repetitive 40 W surge capability, and thermal resistance of 330 K/W to solder point - critical for thermal design in compact DC-DC converters and sensor interface rails.

Technical Context

This Zener diode operates in reverse-biased avalanche mode with a precisely trimmed 51 V nominal working voltage (min 50.49 V, max 51.51 V at I_Z = 2 mA). Its temperature coefficient is +0.05 mV/K, indicating near-zero drift across operating temperature, and it exhibits 400 Ω typical dynamic impedance at rated current - enabling tight regulation under varying load conditions.

The device uses silicon planar epitaxial construction with an anode-cathode-n.c. terminal configuration in SOT23. With 150 °C maximum junction temperature and −65 °C to +150 °C storage range, it supports industrial-grade operation without derating below +125 °C ambient when mounted on standard FR4 PCB.

Key Specifications

Pinout & Package

Package: SOT23 (TO-236AB), surface-mount plastic package with 3 leads, 1.9 mm × 1.1 mm footprint, 1.2 mm height, and tin-plated terminations compatible with reflow and wave soldering per IPC-J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-B51,215, the A-grade offers 2× tighter tolerance for feedback stability; versus MMSZ51T1G, it trades 2× lower power for 5× better accuracy - making it optimal for space-limited, precision analog subsystems rather than high-energy transient suppression.

Availability

BZX84-A51,215 is available at Aetrix Electronics and suitable for industrial power supplies, sensor signal chains, programmable logic controller I/O protection, and medical device voltage references requiring stable component supply and long-term manufacturability.

Supply support for BZX84-A51,215 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 advanced packaging and automotive-qualified components.

The BZX84 series belongs to Nexperia's precision Zener diode product line, engineered specifically for low-power voltage regulation and clamping in consumer, industrial, and computing applications where SMT footprint and parametric consistency are critical.

FAQ

What is the maximum continuous reverse current the BZX84-A51,215 can sustain without exceeding its 250 mW rating?

At 51 V, the maximum continuous reverse current is 4.9 mA (250 mW ÷ 51 V), assuming full power dissipation occurs across the Zener junction. Derating is required above 25 °C ambient per the R_th(j-a) = 500 K/W curve - at 70 °C ambient, usable current drops to ~3.1 mA to maintain T_j ≤ 150 °C.

Can the n.c. pin (Pin 2) be grounded or left floating in PCB layout?

Pin 2 is internally not connected and must remain electrically floating - no PCB trace, pad, or solder mask opening is required. Grounding or routing to any net risks mechanical stress or unintended coupling; Nexperia's package drawings explicitly define it as "not connected" with no internal bond wire.

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 shift is +8.25 mV (0.05 × 165), or +0.016 % of 51 V - negligible for most applications. This near-zero drift is achieved via process-controlled doping and makes the A-grade suitable for environments where thermal cycling would degrade looser-tolerance Zeners.

Is the BZX84-A51,215 suitable for automotive applications?

No - per Nexperia's Revision History (Section 13), the BZX84_SER series was explicitly changed to non-automotive qualification in Rev. 7 (2023). Automotive alternatives require the -Q suffix (e.g., BZX84-A51,215-Q) and undergo AEC-Q101 testing; this part lacks those qualifications and is intended for industrial and commercial use only.