Diodes Incorporated BZX84C3V9S-7

Overview

BZX84C3V9S-7 from Diodes Incorporated is a 3.9 V, 200 mW surface-mount Zener diode in SOT-363 package, rated for 5 mA test current with 90 Ω dynamic impedance at 1 kHz and 3.0 µA maximum reverse leakage at 1.0 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.

For engineers reviewing the BZX84C3V9S-7 datasheet, BZX84C3V9S-7 pinout, BZX84C3V9S-7 application, or BZX84C3V9S-7 equivalent, key selection criteria include nominal Zener voltage tolerance (±5.1%), thermal resistance (625 °C/W), ultra-small footprint compatibility, and RoHS-compliant lead-free plating for high-density PCB layouts.

Technical Context

This dual-anode, single-cathode SOT-363 Zener diode integrates two independent Zener junctions sharing a common cathode terminal (Pin 3), enabling compact dual-rail clamping or reference generation. Its planar die construction ensures stable breakdown characteristics across -65 °C to +150 °C operating range.

The device operates with 5.0 mA nominal Zener test current and exhibits a temperature coefficient of -3.5 to 0 mV/°C - indicating minimal voltage drift over temperature when biased within its specified current range.

Key Specifications

Pinout & Package

Package: SOT-363 (SC-70-6), ultra-small surface-mount plastic case with UL 94V-0 flammability rating, 0.006 g mass, and matte tin-plated Alloy 42 leadframe.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5226BS-7-F and BZX84C3V9LT1G, BZX84C3V9S-7 uniquely provides two matched 3.9 V Zener junctions in one SOT-363 package - reducing component count and layout complexity for dual-rail or redundant reference designs without sacrificing voltage accuracy or thermal performance.

Availability

BZX84C3V9S-7 is available at Aetrix Electronics and suitable for portable power management, industrial sensor signal conditioning, and automotive body control modules requiring stable component supply and long-term lifecycle continuity.

Supply support for BZX84C3V9S-7 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 specifically for voltage regulation, reference, and overvoltage protection in space-constrained, high-reliability applications across consumer, industrial, and automotive markets.

FAQ

What is the maximum reverse voltage (V_R) that BZX84C3V9S-7 can withstand before breakdown?

The BZX84C3V9S-7 has a nominal Zener voltage of 3.9 V with guaranteed breakdown between 3.7 V and 4.1 V at 5 mA test current. It is not rated for reverse blocking above this range - operation beyond 4.1 V initiates controlled Zener conduction, not avalanche failure. The device is designed to regulate, not block, reverse voltage.

Can BZX84C3V9S-7 be used in place of a single Zener diode like BZX84C3V9LT1G?

Yes, but only one of its two Zener junctions (e.g., Pins 2–3 or Pins 4–3) should be used, leaving the other anode floating. The electrical specs match closely: both specify 3.9 V nominal, 5 mA test current, and 90 Ω Z_ZT. However, SOT-363's smaller size and dual topology offer layout advantages where redundancy or dual-rail referencing is required.

How does the SOT-363 package affect thermal performance compared to SOT-23?

The SOT-363 package has higher thermal resistance (625 °C/W vs. ~400–450 °C/W for typical SOT-23 Zeners) due to reduced copper pad area and thinner leadframe. This limits sustained power dissipation to 200 mW at 25 °C ambient. Derating is required above 25 °C - e.g., only ~120 mW at 70 °C ambient - unless enhanced PCB copper pours are used.

Is BZX84C3V9S-7 suitable for high-frequency noise suppression?

No - its typical junction capacitance is ~15 pF at 1 V reverse bias, making it unsuitable for RF filtering or GHz-range decoupling. It is optimized for DC/low-frequency regulation (<1 MHz). For high-frequency ESD clamping, dedicated TVS diodes with sub-nanosecond response and lower capacitance (e.g., <1 pF) are recommended instead.