Diodes Incorporated BZT585B15TQ-13

Overview

BZT585B15TQ from Diodes Incorporated is a precision Zener diode designed for voltage regulation and reference applications in automotive and industrial circuits. It delivers a nominal 15 V Zener voltage with ±2.0% tolerance, 15 Ω dynamic impedance at 5 mA test current, and a positive temperature coefficient of +13.2 mV/°C. Its SOD523 package supports compact, high-reliability designs in power supply feedback loops and overvoltage protection circuits.

For engineers reviewing the BZT585B15TQ datasheet, BZT585B15TQ pinout, BZT585B15TQ application, or BZT585B15TQ equivalent, key selection criteria include its AEC-Q101 qualification, low-profile SOD523 footprint, 350 mW power dissipation rating, and 0.05 µA maximum reverse leakage at 10.5 V.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage under varying load and temperature conditions. Its 15 V nominal Zener voltage is specified at 5 mA test current (IZT), with a typical dynamic impedance of 15 Ω and a maximum of 200 Ω at knee current (IZK = 1 mA).

The device exhibits a +13.2 mV/°C temperature coefficient near 25°C, indicating predictable voltage drift with ambient changes. It is rated for continuous forward current up to 200 mA and reverse voltage up to 10.5 V before significant leakage occurs.

Key Specifications

Pinout & Package

Package: SOD523 - surface-mount, flat-lead, cathode-banded plastic case; dimensions: 1.25 mm (E) × 0.85 mm (D) × 0.65 mm (He) max; moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMSZ5245B-TP and BZX84-C15, the BZT585B15TQ provides tighter voltage tolerance, automotive qualification, and a smaller SOD523 footprint-making it optimal for space-constrained, safety-compliant automotive modules where regulation accuracy and supply-chain traceability are mandatory.

Availability

BZT585B15TQ is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC analog inputs, medical infusion pump monitoring, and telecom remote radio unit bias supplies requiring stable component supply and full AEC-Q101 traceability.

Supply support for BZT585B15TQ 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 distribution operations across Asia, Europe, and North America.

The BZT585 series belongs to Diodes' precision Zener diode product line, engineered specifically for automotive and industrial voltage reference and protection applications demanding AEC-Q101 reliability, tight tolerances, and green material compliance.

FAQ

What is the maximum reverse voltage this Zener can withstand before breakdown?

The BZT585B15TQ has a nominal Zener voltage of 15.0 V, with a guaranteed breakdown range of 14.7 V to 15.3 V at 5 mA test current. It begins conducting significantly above 10.5 V, where reverse leakage reaches 0.05 µA - this is the practical upper limit for non-breakdown operation. Full regulation occurs only within the specified VZ window.

Is this part suitable for use in high-temperature under-hood automotive environments?

Yes. The BZT585B15TQ is AEC-Q101 qualified and rated for operation from –65°C to +150°C. Its thermal resistance (RθJA = 357°C/W) and power derating curve confirm reliable performance at 125°C ambient when mounted per the recommended SOD523 pad layout, making it suitable for engine control units and transmission control modules.

How does the +13.2 mV/°C temperature coefficient affect circuit accuracy?

The +13.2 mV/°C coefficient means the Zener voltage increases by approximately 13.2 mV per degree Celsius rise in junction temperature. Over a 100°C range (–40°C to +60°C), this results in ~1.32 V drift - a known, linear error that can be compensated in system-level calibration or mitigated using complementary TC components in reference divider networks.

Can this Zener diode replace a 1N4744A in an existing design?

No - the 1N4744A is a through-hole 14 V Zener in DO-41 package with ±5% tolerance and 1 W power rating. The BZT585B15TQ is a 15 V, ±2% surface-mount device with 350 mW rating and different thermal behavior. Direct replacement would require PCB redesign, thermal validation, and tolerance re-evaluation; it is not a drop-in substitute.