Diodes Incorporated BZX84C39S-7

Overview

BZX84C39S-7 from Diodes Incorporated is a dual 200 mW surface-mount Zener diode in SOT-363 package, rated for 39 V nominal Zener voltage (37–41 V range at 2 mA), with 130 Ω maximum Zener impedance at test current and 0.1 µA maximum reverse leakage at 27.3 V. It serves as a precision voltage reference or overvoltage clamp in low-power analog signal conditioning circuits.

For engineers reviewing the BZX84C39S-7 datasheet, BZX84C39S-7 pinout, BZX84C39S-7 application, or BZX84C39S-7 equivalent, key selection criteria include Zener voltage tolerance, dynamic impedance at low test current (2 mA), thermal resistance (625 °C/W), and SOT-363 dual-diode layout for space-constrained biasing or dual-rail protection.

Technical Context

This device integrates two independent Zener diodes in a single ultra-small SOT-363 package, sharing no internal connection - each diode operates as a discrete 39 V reference with identical electrical specs. It uses planar die construction for stable breakdown characteristics and low temperature coefficient (33.4 to 41.2 mV/°C).

The 200 mW power rating is derated linearly above 25 °C ambient per a defined curve (0 mW at 150 °C), and its 625 °C/W junction-to-ambient thermal resistance assumes mounting on FR4 with Diodes Inc.'s recommended pad layout. Reverse leakage remains ≤0.1 µA up to 27.3 V, enabling high-impedance sensing node stabilization.

Key Specifications

Pinout & Package

SOT-363 package: 6-pin, dual-row, ultra-small surface-mount outline with exposed thermal pad not present; molded plastic case (UL 94V-0), moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5277BS-7-F and BZX84C39LT1G, BZX84C39S-7 uniquely delivers dual 39 V Zeners in one SOT-363 - reducing component count and interconnect inlays while maintaining low leakage and predictable 2 mA test-point regulation essential for precision analog designs.

Availability

BZX84C39S-7 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB-C power delivery clamp circuits, medical wearable battery monitors, and automotive body control module bias networks requiring stable component supply and RoHS-compliant sourcing.

Supply support for BZX84C39S-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, specializing in high-reliability, cost-optimized components for industrial, computing, and consumer markets.

The BZX84C39S-7 belongs to the BZX84C series of dual Zener diodes designed specifically for space-constrained voltage reference and overvoltage protection in portable and embedded systems.

FAQ

What is the maximum reverse voltage before breakdown for BZX84C39S-7?

The BZX84C39S-7 exhibits sharp Zener breakdown at 39 V nominal, with guaranteed operation between 37 V (min) and 41 V (max) at 2 mA test current. Below 27.3 V, reverse leakage stays ≤0.1 µA - confirming stable non-conduction until near the rated Zener point.

Can BZX84C39S-7 be used in place of a single Zener diode?

Yes - either diode (C1/A1 or C2/A2) functions independently as a full-spec 39 V Zener. The NC pins (1 and 6) must remain unconnected. Using only one diode retains all electrical specs, though the unused terminals introduce negligible parasitic capacitance (~1.5 pF).

Is thermal derating required for continuous operation at 50°C ambient?

Yes - at 50°C ambient, power dissipation must be reduced to 150 mW per the linear derating curve (200 mW − (50−25) × 0.8 mW/°C). This ensures junction temperature remains within −65 to +150°C limits when mounted per Diodes Inc.'s recommended FR4 pad layout.

Does BZX84C39S-7 support bidirectional transient suppression?

No - it is a unidirectional Zener device. Each diode conducts only in reverse breakdown (cathode positive relative to anode). Forward conduction occurs at ~0.9 V (VF @ 10 mA), but this is not rated for surge handling; dedicated TVS diodes are required for bidirectional ESD/transient protection.