Diodes Incorporated FZT855QTA

Overview

FZT855QTA from Diodes Incorporated is a 150V NPN high-voltage transistor in SOT223 package, designed for switching and linear regulation in automotive and industrial power stages. It delivers 5A continuous collector current, 150V V_CEO, <110mV V_CE(sat) at 1A, 50mΩ R_CE(sat), and AEC-Q101 qualification - used in DC-DC converter primary-side switches and motor driver high-side stages.

For engineers reviewing the FZT855QTA datasheet, FZT855QTA pinout, FZT855QTA application, or FZT855QTA equivalent, key selection criteria include high-voltage blocking (150V), low on-resistance (50mΩ), thermal performance (R_θJA = 42°C/W on 52mm × 52mm PCB), and automotive-grade reliability (IATF16949 manufacturing, PPAP-capable).

Technical Context

This NPN bipolar junction transistor operates in saturation and active regions for high-efficiency switching and analog amplification. Its 250V V_CBO, 150V V_CEO, and 7V V_EBO enable robust operation in 48V–100V bus systems with transient margin. The h_FE of 100–300 (up to 10A) supports stable base-driven control without excessive drive loss.

Thermal design leverages low R_θJL = 8.8°C/W (junction-to-lead) and 42°C/W R_θJA under standard FR4 layout, enabling 3W continuous dissipation. ESD ratings (4kV HBM, 400V MM) meet industrial handling requirements without external protection.

Key Specifications

Pinout & Package

Package: SOT223 - Surface-mount plastic package with exposed collector tab for thermal and electrical connection; UL 94V-0 rated, 0.112g mass, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZXTN2012G and MJD127G, FZT855QTA uniquely combines 150V blocking, AEC-Q101 qualification, SOT223 surface-mount compatibility, and halogen-free construction - making it the only option for automotive 48V+ systems requiring both high voltage and regulatory compliance in compact layouts.

Availability

FZT855QTA is available at Aetrix Electronics and suitable for automotive LED drivers, industrial 48V DC-DC converters, and brushed DC motor controllers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for FZT855QTA 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 power management, signal integrity, and protection solutions.

FZT855QTA belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for automotive and industrial power switching applications demanding AEC-Q101 compliance, low saturation loss, and robust thermal performance in SMT packages.

FAQ

What is the maximum safe operating temperature for FZT855QTA?

The FZT855QTA has an operating junction temperature range of –55°C to +150°C. Its absolute maximum storage temperature matches this range. Derating begins above +25°C ambient per the linear derating factor of 24 mW/°C (on 52mm × 52mm PCB), limiting usable power dissipation to maintain T_J ≤ 150°C.

Is FZT855QTA pin-compatible with other SOT223 NPN transistors?

FZT855QTA uses standard SOT223 pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector (tab). While mechanical footprint matches most SOT223 NPNs, electrical compatibility requires verification of V_CEO, I_C, h_FE, and thermal specs - e.g., ZXTN2012G shares the package but only supports 100V, not 150V.

Does FZT855QTA require a heatsink in typical applications?

With R_θJA = 42°C/W on a 52mm × 52mm 2oz copper PCB, FZT855QTA dissipates up to 3W continuously without external heatsink. At 5A and 110mV V_CE(sat), power loss is ~0.55W - well within this limit. Heatsinking is unnecessary unless ambient exceeds +85°C or PCB copper area is reduced.

How does the AEC-Q101 qualification impact FZT855QTA's use in non-automotive designs?

AEC-Q101 qualification confirms extended stress testing (HTOL, TC, UHAST, etc.) and IATF16949 manufacturing controls - delivering higher reliability, tighter parametric consistency, and documented failure modes. These benefits directly improve field lifetime and reduce qualification effort in industrial, medical, and aerospace applications, even when automotive compliance isn't mandated.