Diodes Incorporated FZT955TC

Overview

FZT955TC from Diodes Incorporated is a PNP silicon planar high-current bipolar junction transistor in SOT-223 package, rated for −4 A continuous collector current and −140 V collector-emitter breakdown voltage, with V_CE(sat) = −110 mV at I_C = −1 A / I_B = −100 mA, used in high-efficiency linear regulators and industrial DC-DC converter output stages.

For engineers reviewing the FZT955TC datasheet, FZT955TC pinout, FZT955TC application, or FZT955TC equivalent, key selection criteria include guaranteed h_FE ≥ 75 at I_C = −3 A, low V_CE(sat) across temperature, safe operating area up to 100°C ambient, and complementary pairing with FZT855 for push-pull designs.

Technical Context

This PNP transistor employs planar epitaxial construction for stable gain and low leakage, with specified h_FE of 100–300 at I_C = −10 mA to −10 A and V_CE = −5 V. Its f_T = 110 MHz enables use in medium-frequency switching applications up to 50 MHz.

V_CE(sat) remains ≤ −150 mV up to I_C = −3 A with I_B/I_C = 0.1, and V_BE(sat) is −1110 mV at I_C = −3 A / I_B = −300 mA, supporting robust base drive in high-current linear amplification.

Key Specifications

Pinout & Package

SOT-223 package with standard 4-pin configuration (3 active pins + tab), thermally enhanced plastic body, 1.5 mm pitch, and exposed emitter pad for direct PCB thermal coupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-current transistor applications.

Compared with ZTX951 and MJD2955G, FZT955TC uniquely balances SOT-223 surface-mount compatibility, −140 V rating, and sub-150 mV saturation in a single component-making it optimal for space-constrained 24–48 V industrial power stages where thermal and voltage margins are critical.

Availability

FZT955TC is available at Aetrix Electronics and suitable for industrial linear regulators, DC-DC converter output stages, motor control H-bridges, and automotive body controllers requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for FZT955TC 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 semiconductor company specializing in discrete, analog, and mixed-signal devices, with focus on high-reliability power management and signal integrity solutions.

FZT955TC belongs to the FZT series of high-performance PNP transistors designed specifically for industrial and automotive power switching applications demanding high voltage, high current, and stable gain over temperature.

FAQ

Is FZT955TC RoHS compliant and lead-free?

Yes, FZT955TC is RoHS compliant and lead-free per Diodes Incorporated's standard qualification. The device meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1), and its SOT-223 package uses matte tin plating on all terminations with no lead content above 1000 ppm threshold.

What is the maximum allowable PCB copper area for thermal performance?

The datasheet specifies "copper equal to 4 square inch minimum" for full 3 W power dissipation at T_amb = 25°C. Using less than 4 in² reduces P_tot linearly; at 2 in², max dissipation drops to ~2.1 W. Thermal vias under the emitter tab improve performance by up to 25%.

Can FZT955TC replace FZT955 in existing designs?

Yes, FZT955TC is the tape-and-reel packaging variant of FZT955 and shares identical electrical, thermal, and mechanical specifications. The "TC" suffix denotes carrier tape format only; no parameter or reliability differences exist between FZT955 and FZT955TC.

Does FZT955TC require a base resistor in switching applications?

Yes - base current must be actively limited. With V_BE(on) ≈ −830 mV and typical h_FE = 100, driving −1 A collector current requires −10 mA base current. A 470 Ω resistor from 0 V to base yields −10.2 mA with 5 V logic swing, ensuring saturation while avoiding excessive base dissipation.