Diodes Incorporated BZT585B3V9TQ-13

Overview

BZT585B3V9TQ from Diodes Incorporated is a precision Zener diode with 3.9 V nominal breakdown voltage (±2.0% tolerance), 350 mW power dissipation, and SOD523 package. It operates as a voltage reference or overvoltage clamp in low-power analog circuits, automotive sensor signal conditioning, and microcontroller I/O protection.

For engineers reviewing the BZT585B3V9TQ datasheet, BZT585B3V9TQ pinout, BZT585B3V9TQ application, or BZT585B3V9TQ equivalent, key selection criteria include Zener voltage accuracy, low temperature coefficient (−1.9 mV/°C), low reverse leakage (3 µA @ 1 V), and AEC-Q101 qualification for automotive use.

Technical Context

This Zener diode uses silicon planar construction to achieve tight voltage tolerance and stable regulation under low-current conditions (IZT = 5 mA). Its −1.9 mV/°C temperature coefficient ensures minimal drift across −65°C to +150°C operating range.

The device features a cathode-band-marked SOD523 package with matte tin–annealed Alloy 42 leads, rated for 200 mA forward current and optimized for high thermal resistance control (RθJA = 357°C/W on FR-4).

Key Specifications

Pinout & Package

Package: SOD523 - surface-mount, flat-lead, low-profile plastic package (0.001 g weight, UL 94V-0 rating). Cathode identified by band marking on top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMSZ4V3T1G and BZX84-C3V9, BZT585B3V9TQ delivers superior voltage accuracy, automotive-grade reliability, and smallest footprint-making it optimal for next-generation ADAS sensor modules and compact medical electronics.

Availability

BZT585B3V9TQ is available at Aetrix Electronics and suitable for automotive cabin sensors, industrial PLC analog inputs, USB-C port protection, and medical wearable battery monitoring requiring stable component supply and AEC-Q101 compliance.

Supply support for BZT585B3V9TQ 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 BZT585 series belongs to Diodes' precision Zener diode product line, engineered specifically for automotive and industrial applications demanding high stability, low profile, and rigorous qualification.

FAQ

What is the maximum continuous Zener current for BZT585B3V9TQ?

The device is rated for 350 mW total power dissipation. At its nominal 3.9 V Zener voltage, this corresponds to a maximum continuous Zener current of approximately 89.7 mA (350 mW ÷ 3.9 V). Derating per Figure 1 applies above 25°C ambient.

Is BZT585B3V9TQ compatible with lead-free reflow soldering processes?

Yes. The device uses matte tin–annealed Alloy 42 leads and is fully RoHS 3 compliant. It meets JEDEC J-STD-020 moisture sensitivity Level 1 and is qualified for standard Pb-free reflow profiles up to 260°C peak temperature.

How does the −1.9 mV/°C temperature coefficient affect circuit performance?

This negative coefficient means the Zener voltage decreases by 1.9 mV per degree Celsius rise. Over a 100°C range (−40°C to +60°C), voltage shift is ~190 mV-within specification for most 3.3 V system references, especially when paired with temperature-compensated designs.

Can BZT585B3V9TQ be used in place of a 3.3 V Zener diode?

No. Its nominal Zener voltage is 3.9 V (3.82–3.98 V), not 3.3 V. Substituting it for a 3.3 V Zener would result in incorrect clamping or reference levels. For 3.3 V applications, consider BZT585B3V3TQ (if available) or MMBZ5226BS.