Diodes Incorporated FZT855TC

Overview

FZT855 from Diodes Incorporated is a 150V NPN medium-power transistor in SOT223 package, designed for high-voltage switching and linear regulation. It delivers 5A continuous collector current, <110mV V_CE(sat) at 1A, and 50mΩ equivalent on-resistance, enabling efficient operation in automotive power supplies and industrial motor drivers.

For engineers reviewing the FZT855 datasheet, FZT855 pinout, FZT855 application, or FZT855 equivalent, key selection criteria include its 150V V_CEO, 10A peak pulse rating, high gain hold-up to 10A (h_FE ≥ 10), low thermal resistance (R_θJL = 8.8°C/W), and AEC-Q101 readiness for automotive-grade reliability validation.

Technical Context

This NPN bipolar junction transistor operates with a minimum BV_CEO of 150V and supports linear derating up to 3.0W on 52mm × 52mm 2oz copper PCBs. Its V_CE(sat) remains below 110mV at 1A/100mA drive, and h_FE is specified across 10mA–10A range, ensuring stable gain under heavy load transients.

The device features 8.8°C/W junction-to-lead thermal resistance and 42°C/W junction-to-ambient (on large copper), enabling robust thermal management in compact power stages. ESD ratings meet JEDEC Class 3B (≥8kV HBM), supporting handling in automated assembly environments without special precautions.

Key Specifications

Pinout & Package

Package: SOT223 (Type DN), surface-mount, molded plastic with matte tin-plated leads; UL 94V-0 rated, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-voltage switching transistor applications.

Compared with ZXTN2012E6TA and MJD127G, FZT855 uniquely balances 150V blocking, SMT compatibility, and 5A capability in a single SOT223 footprint-enabling scalable, automotive-ready power stages without trade-offs in voltage margin, thermal performance, or manufacturability.

Availability

FZT855 is available at Aetrix Electronics and suitable for industrial motor control, automotive power supply, and telecom DC-DC converter designs requiring stable component supply and long-term lifecycle support.

Supply support for FZT855 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.

FZT855 belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for ruggedized power switching in automotive, industrial, and telecom infrastructure where reliability, thermal efficiency, and AEC-Q101 readiness are mandatory.

FAQ

What is the maximum safe operating voltage for FZT855 in continuous DC applications?

The absolute maximum collector-emitter voltage (V_CEO) is 150V at T_A = +25°C. For reliable long-term operation, Diodes recommends limiting steady-state V_CE to ≤120V to maintain margin against transients, temperature derating, and process variation. At 100°C junction temperature, V_CEO derates to approximately 135V per the datasheet's safe operating area curve.

Can FZT855 replace a MOSFET in low-side switching applications?

FZT855 can replace low-voltage MOSFETs in cost-sensitive, moderate-speed (<100kHz) low-side switches where V_BE drive is available and 110mV V_CE(sat) is acceptable. Unlike MOSFETs, it requires sustained base current (e.g., 500mA at 5A I_C), so gate drivers must be sized accordingly-not suitable for high-frequency or zero-static-current applications.

Is FZT855 qualified for automotive use per AEC-Q101?

FZT855 is manufactured in IATF 16949-certified facilities and supports PPAP documentation. While not pre-qualified in standard distribution, Diodes offers AEC-Q101 qualification upon customer request with defined test plans and change control-required for deployment in safety-critical vehicle subsystems like body control modules or ADAS power domains.

How does the SOT223 package's thermal performance compare between 1oz and 2oz copper PCBs?

On a 52mm × 52mm PCB with 2oz copper, R_θJA is 42°C/W, allowing 3.0W dissipation at 25°C ambient. With 1oz copper (25mm × 25mm), R_θJA rises to 78°C/W and max power drops to 1.6W. The 8.8°C/W R_θJL remains constant-so attaching the collector tab directly to a heatsink bypasses ambient limitations entirely.