Nexperia USA Inc. BZX84W-C3V9-QF

Overview

BZX84W-C3V9-QF from Nexperia is a ±5 % tolerance Zener diode in SOT323 (SC-70) package, rated for 3.9 V nominal regulation voltage at 5 mA, with 275 mW total power dissipation and 3 µA reverse leakage at 1 V, used for precision voltage reference and overvoltage protection in automotive power rails.

For engineers reviewing the BZX84W-C3V9-QF datasheet, BZX84W-C3V9-QF pinout, BZX84W-C3V9-QF application, or BZX84W-C3V9-QF equivalent, this page delivers verified Zener parameters, AEC-Q101 qualification status, thermal resistance (455 K/W), differential resistance (90 Ω), and temperature coefficient (−2.5 mV/K) to support automotive-grade voltage stabilization design.

Technical Context

This Zener diode operates in reverse-bias breakdown mode with a tightly controlled 3.9 V nominal Zener voltage (V_Z) at I_Z = 5 mA and ±5 % tolerance. Its low 90 Ω differential resistance ensures stable regulation under load variation, while the negative −2.5 mV/K temperature coefficient minimizes drift across −55 °C to +150 °C ambient range.

Qualified per AEC-Q101, it supports automotive applications requiring robust transient immunity and long-term reliability. The SOT323 package enables high-density PCB layout, and its 3 µA reverse current at V_R = 1 V confirms low standby leakage critical for battery-sensitive systems.

Key Specifications

Pinout & Package

The BZX84W-C3V9-QF is housed in a leadless SOT323 (SC-70) surface-mount plastic package measuring 2.2 mm × 1.35 mm × 0.95 mm, optimized for automated reflow assembly and space-constrained automotive modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84W-C3V9-QF, the BZX84-C3V9,115 offers higher power but lacks automotive qualification, while MMSZ4685T1G provides greater surge margin and same qualification at the cost of larger size-making BZX84W-C3V9-QF optimal for space-constrained AEC-Q101 designs needing exact 3.9 V regulation.

Availability

BZX84W-C3V9-QF is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, and USB-C power monitoring requiring stable component supply with full traceability and lifecycle management.

Supply support for BZX84W-C3V9-QF 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 essential efficiency technologies, delivering high-performance, reliable discrete and logic devices for automotive, industrial, and mobile markets.

The BZX84W-Q series belongs to Nexperia's AEC-Q101-qualified Zener diode product line, engineered specifically for robust voltage regulation and transient suppression in harsh automotive environments.

FAQ

What is the maximum reverse voltage the BZX84W-C3V9-QF can withstand before breakdown?

The BZX84W-C3V9-QF has a nominal Zener voltage of 3.9 V at 5 mA test current, with a guaranteed breakdown range of 3.70 V to 4.10 V due to its ±5 % tolerance. It does not specify a distinct 'maximum reverse voltage'-operation above 4.10 V in reverse bias initiates controlled Zener conduction, not catastrophic failure, provided power dissipation remains within 275 mW limits.

Is the n.c. pin (pin 2) required to be grounded or left floating on the PCB?

Pin 2 is internally not connected and must remain unconnected on the PCB-neither grounded nor tied to any net. Routing copper or solder mask over this pad is acceptable, but intentional electrical connection violates the device's mechanical and thermal design and may compromise reliability or cause parametric shift.

How does the −2.5 mV/K temperature coefficient affect regulation accuracy over temperature?

At a 100 °C temperature span (e.g., −40 °C to +60 °C), the −2.5 mV/K coefficient causes approximately 250 mV total drift in V_Z, resulting in ~6.4 % deviation from nominal 3.9 V. This is fully specified and accounted for in automotive system-level tolerance budgets; compensation is unnecessary if system design accommodates this known linear drift.

Can BZX84W-C3V9-QF be used in place of a 3.3 V Zener diode for logic-level clamping?

No-its 3.9 V nominal Zener voltage exceeds standard 3.3 V logic thresholds and would not clamp effectively below that level. Using it for 3.3 V rail protection risks allowing damaging overvoltage to reach downstream ICs; a dedicated 3.3 V Zener such as BZX84W-C3V3-QF (3.3 V ±5 %) is required for accurate clamping at that voltage.