Diodes Incorporated BZT52C3V9LP-7

Overview

BZT52C3V9LP-7 from Diodes Incorporated is a surface-mount Zener diode with a nominal zener voltage of 3.9 V, ±5% tolerance (3.7–4.1 V), 250 mW power dissipation, and 90 Ω maximum zener impedance at 5 mA test current. It serves as a precision voltage reference or overvoltage clamp in low-power analog sensing and regulator feedback paths.

For engineers reviewing the BZT52C3V9LP-7 datasheet, BZT52C3V9LP-7 pinout, BZT52C3V9LP-7 application, or BZT52C3V9LP-7 equivalent, key selection criteria include its DFN1006-2 package footprint, AEC-Q101 qualification for automotive reliability, 3 µA maximum reverse leakage at 1 V, and -3.5 to 0 mV/°C temperature coefficient range.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable voltage regulation across varying load currents. Its 5 mA zener test current and 90 Ω dynamic impedance ensure predictable clamping behavior under transient conditions.

The device uses a planar silicon junction structure optimized for low leakage and tight voltage tolerance. Its thermal resistance of 500 °C/W (junction-to-ambient) and operating range of -65 °C to +150 °C support use in thermally constrained PCB layouts and harsh-environment applications.

Key Specifications

Pinout & Package

Package: DFN1006-2, 2-terminal surface-mount package with cathode indicated by dot marking. Terminals are NiPdAu-plated copper leadframe, solderable per MIL-STD-202 Method 208.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMSZ4V3T1G and BZX384-C3V9, BZT52C3V9LP-7 offers the smallest PCB area (0.6 mm²), AEC-Q101 qualification for automotive use, and lowest profile (0.3 mm max height), making it optimal for ultra-thin consumer and automotive modules where volume and reliability are prioritized over raw power handling.

Availability

BZT52C3V9LP-7 is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor signal conditioning, and portable medical device design requiring stable component supply and long-term lifecycle assurance.

Supply support for BZT52C3V9LP-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 components for automotive, industrial, and computing markets.

The BZT52CxxLP series belongs to Diodes' AEC-Q101-qualified Zener diode portfolio, designed specifically for precision voltage reference and overvoltage protection in space- and power-constrained automotive and industrial systems.

FAQ

What is the maximum reverse voltage (V_R) this diode can withstand before breakdown?

The BZT52C3V9LP-7 has a nominal zener voltage of 3.9 V with a guaranteed breakdown range of 3.7–4.1 V at 5 mA test current. It is not rated for forward blocking; its reverse breakdown is intentional and controlled. The absolute maximum reverse voltage is defined by its 250 mW power limit - exceeding ~64 mA at 3.9 V risks thermal failure.

Is this part suitable for use in a 3.3 V system's I/O protection circuit?

Yes - with proper current limiting, it clamps transients above ~4.1 V while presenting only 3 µA leakage at 1 V reverse bias. Its 3.9 V zener voltage provides safe margin above 3.3 V logic levels, and its DFN1006-2 package allows placement directly at connector or IC pin for effective ESD/transient suppression.

Does the cathode dot marking align with standard PCB silkscreen conventions?

Yes - the cathode dot on the BZT52C3V9LP-7 top surface corresponds to the cathode terminal, matching IPC-7351 standard orientation for DFN1006-2 packages. When viewed from the top with the dot at upper-left, the left pad is cathode and right pad is anode, consistent with industry layout tools and pick-and-place machine vision alignment.

How does its thermal resistance affect derating in a 60 °C ambient environment?

With R_θJA = 500 °C/W, junction temperature rise is 125 °C at full 250 mW dissipation. At 60 °C ambient, maximum allowable power drops to (150 − 60)/500 = 180 mW. Derating curves in DS30506 Rev. 16 confirm 180 mW at 60 °C, requiring current limiting to ≤46 mA for sustained operation.