Diodes Incorporated ZX5T851GTA

Overview

ZX5T851GTA from Diodes Incorporated is a 60V NPN medium-power low-saturation transistor in SOT223 package, rated for 6A continuous collector current and 20A peak pulse current, with V_CE(sat) < 60mV at –1A and h_FE ≥ 100 up to 10A - used in MOSFET/IGBT gate drivers and solenoid/relay control circuits.

For engineers reviewing the ZX5T851GTA datasheet, ZX5T851GTA pinout, ZX5T851GTA application, or ZX5T851GTA equivalent, key selection criteria include guaranteed high-current gain stability at 5–10A, AEC-Q101 qualification for automotive-grade reliability, low R_SAT (35mΩ), and complementary PNP pairing with ZX5T951G.

Technical Context

This NPN bipolar junction transistor operates as a high-current, low-V_CE(sat) switching device with BVCBO = 150V and BVCEO = 60V, supporting robust operation under inductive load transients. Its h_FE remains ≥55 at IC = 5A and ≥20 at IC = 10A, enabling stable drive capability across wide current ranges.

Thermal design is enabled by R_θJA = 41.7°C/W (on 50mm × 50mm 2oz Cu) and R_θJL = 10.5°C/W, while ESD ratings meet HBM 4kV and MM 400V per JEDEC standards - critical for gate driver and motor control environments subject to electrical noise.

Key Specifications

Pinout & Package

Package: SOT223 - surface-mount, thermally enhanced plastic case with exposed collector tab for PCB heat sinking; UL 94V-0 rated, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN medium-power switching applications.

Compared with ZX5T851GTA, ZX5T951G offers matched thermal and package characteristics for complementary switching, while MMBT5551 lacks current rating, saturation performance, and automotive qualification - making it unsuitable for direct substitution in high-power driver roles.

Availability

ZX5T851GTA is available at Aetrix Electronics and suitable for emergency lighting circuits, MOSFET/IGBT gate drivers, and solenoid/relay drivers requiring stable component supply and AEC-Q101-compliant reliability.

Supply support for ZX5T851GTA 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 consumer markets.

ZX5T851GTA belongs to Diodes' power transistor product line, engineered specifically for high-current, low-saturation switching in automotive-grade driver and actuator control applications.

FAQ

What is the maximum safe operating temperature for ZX5T851GTA?

The ZX5T851GTA has an operating junction temperature range of –55°C to +150°C. Its absolute maximum rating is defined by thermal derating: at 25°C ambient, max power dissipation is 3.0W on 50mm×50mm 2oz copper; this drops linearly to zero at +150°C junction temperature. Thermal resistance to lead (R_θJL) is 10.5°C/W, enabling precise thermal modeling in PCB layouts.

Does ZX5T851GTA require a heatsink in typical applications?

No external heatsink is required if the SOT223 collector tab is soldered to ≥25mm² of 2oz copper on FR4 PCB. With that layout, R_θJA is 62.5°C/W (25mm×25mm 2oz Cu), allowing 6A continuous operation at ambient ≤60°C. Smaller pads increase thermal resistance and may necessitate reduced current or forced airflow.

How does the base drive requirement scale with collector current?

For reliable saturation at 6A, the datasheet specifies IB = 300mA (IC/IB = 20). At 1A, IB = 100mA suffices (IC/IB = 10); at 100mA, IB = 5mA is adequate. The h_FE degrades with current - from 200 at 10mA to 20 at 10A - so base drive must be scaled accordingly to maintain low V_CE(sat).

Is ZX5T851GTA pin-compatible with other SOT223 transistors?

ZX5T851GTA follows standard SOT223 pinout (Emitter-Base-Collector-Tab), matching industry conventions. However, electrical characteristics - especially V_CE(sat), h_FE, and thermal resistance - differ significantly from generic SOT223 transistors. Direct replacement requires validation of gain, saturation voltage, and thermal performance in the target circuit.