Diodes Incorporated BZX84C3V9S-7-F

Overview

BZX84C3V9S-7-F from Diodes Incorporated is a dual 200mW surface-mount Zener diode in SOT-363 package, rated for nominal 3.9V zener voltage (3.7–4.1V range at 5mA), with 90Ω max zener impedance at test current and 3.0μA max reverse leakage at 1.0V. It serves as a precision voltage reference or overvoltage clamp in low-power analog signal conditioning circuits.

For engineers reviewing the BZX84C3V9S-7-F datasheet, BZX84C3V9S-7-F pinout, BZX84C3V9S-7-F application, or BZX84C3V9S-7-F equivalent, key selection criteria include zener voltage tolerance, dynamic impedance at 5mA, thermal resistance (625°C/W), reverse leakage at VR=1.0V, and SOT-363 footprint compatibility with high-density PCB layouts.

Technical Context

This dual-element Zener diode integrates two independent 3.9V zener junctions in a single SOT-363 package, sharing no internal connection - each anode-cathode pair operates independently. Its planar die construction ensures stable breakdown characteristics across temperature (-65°C to +150°C) and supports reliable operation under pulsed conditions per short-duration test methodology.

The device exhibits a negative temperature coefficient of -3.5 to 0 mV/°C at IZT = 5mA, enabling predictable drift behavior in bias networks. With 200mW total power dissipation and 625°C/W junction-to-ambient thermal resistance on FR4 board, derating begins above 25°C ambient per the published power derating curve.

Key Specifications

Pinout & Package

Package: SOT-363 (SC-70-6), ultra-small surface-mount plastic case with UL 94V-0 flammability rating, moisture sensitivity level 1, and matte tin lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84C3V9S-7-F, MMBZ5227BS-7-F offers superior regulation at higher currents but lacks dual-channel isolation; BZX84C3V9LT1G provides identical voltage performance in a simpler single-diode format but consumes more PCB area and cannot support two independent clamped nodes.

Availability

BZX84C3V9S-7-F is available at Aetrix Electronics and suitable for low-power voltage reference, ESD protection, DC-DC feedback stabilization, and microcontroller reset supervision requiring stable component supply and long-term lifecycle continuity.

Supply support for BZX84C3V9S-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The BZX84 series belongs to Diodes' precision Zener diode product line, engineered for stable voltage regulation and transient suppression in space-constrained, cost-sensitive consumer and industrial electronics.

FAQ

What is the maximum continuous power dissipation for BZX84C3V9S-7-F?

The device is rated for 200mW total power dissipation at 25°C ambient when mounted on FR4 with recommended pad layout per AP02001. Derating is linear at 1.6mW/°C above 25°C, reaching zero dissipation at 150°C ambient, per the published power derating curve.

How are the two Zener diodes configured inside the SOT-363 package?

The two Zener elements are fully independent - Cathode 1 (Pin 2) and Anode 1 (Pin 3) form one diode; Cathode 2 (Pin 5) and Anode 2 (Pin 4) form the second. Pins 1 and 6 are unconnected. No internal connection exists between the two diodes.

Is BZX84C3V9S-7-F suitable for ESD protection per IEC 61000-4-2?

While not rated or characterized as a dedicated ESD protection device, its 3.9V breakdown and low capacitance (<10pF typical) enable effective clamping of low-energy transients on signal lines. For certified IEC 61000-4-2 Level 4 protection, a TVS diode with specified clamping voltage and peak pulse power is recommended instead.

What does the "-7-F" suffix indicate in the part number?

The "-7-F" suffix denotes tape-and-reel packaging: 3,000 units per reel, with "F" indicating lead-free/RoHS-compliant finish and "7" specifying the SOT-363 package variant. This matches Diodes Incorporated's standard ordering convention documented in DS30108 Rev. 17.