Diodes Incorporated FZT948TC

Overview

FZT948TC from Diodes Incorporated is a 20V PNP medium-power transistor in SOT223 package, rated for -6A continuous collector current and -20A peak pulse current, with low V_CE(sat) down to -360 mV at -6A/-250mA drive, and DC current gain (h_FE) of 60–130 at -10A. It serves as a high-current switching or linear amplification device in automotive power management and industrial motor control circuits.

For engineers reviewing the FZT948TC datasheet, FZT948TC pinout, FZT948TC application, or FZT948TC equivalent, key selection criteria include its -20V V_CEO, thermal resistance of 42°C/W (52 mm × 52 mm 2 oz Cu), ESD HBM rating of 4 kV, and specified h_FE hold-up to -20A - critical for robust base-driven switching in high-temperature environments.

Technical Context

The FZT948TC operates as a silicon PNP bipolar junction transistor with a maximum collector-emitter breakdown voltage of -20 V and emitter-base breakdown of -7 V. Its safe operating area supports pulsed currents up to -20 A with defined derating curves for 25 mm × 25 mm and 52 mm × 52 mm copper layouts.

It features a transitional frequency (f_T) of 80 MHz at -100 mA/-10 V, enabling moderate-speed switching applications. The device's V_BE(sat) of -1.05 V at -5A/-300mA and V_BE(on) of -870 mV at -6A confirm strong base drive capability under high-current saturation conditions.

Key Specifications

Pinout & Package

Package: SOT223 (Type DN), surface-mount, 4-pin outline with collector tab (pin 1), emitter (pin 2), base (pin 3), and collector (pin 4) - pin 1 and pin 4 internally connected to the same collector lead.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power transistor applications.

Compared with ZXTN25050DFH and MJD2955T4G, the FZT948TC delivers optimal balance of current density, thermal efficiency in SMT form factor, and automotive-grade reliability - making it preferred for space-constrained, high-reliability 12–24 V systems where -20 V blocking suffices.

Availability

FZT948TC is available at Aetrix Electronics and suitable for automotive body control modules, industrial motor drivers, LED constant-current regulators, and telecom OR-ing circuits requiring stable component supply and AEC-Q101-compliant manufacturing traceability.

Supply support for FZT948TC 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 sales operations across Asia, Europe, and North America.

The FZT948TC belongs to Diodes' high-reliability PNP transistor family designed specifically for automotive and industrial power switching applications demanding robust SOA, high-current gain retention, and green packaging compliance.

FAQ

What is the maximum junction temperature for continuous operation of the FZT948TC?

The FZT948TC has an operating junction temperature range of -55°C to +150°C. For continuous operation at full -6 A current, the maximum ambient temperature must be limited to approximately +108°C when mounted on a 52 mm × 52 mm 2 oz copper PCB, based on its 42°C/W R_θJA and 3.0 W power dissipation rating - exceeding this requires forced cooling or derating.

Is the FZT948TC pin-compatible with other SOT223 PNP transistors like the FZT788B?

No, the FZT948TC is not pin-compatible with the FZT788B. While both use SOT223, the FZT948TC has collector-tab (pin 1) and collector (pin 4) tied together, whereas the FZT788B uses pin 1 as emitter, pin 2 as base, and pin 3 as collector - different pin assignments require PCB layout revision for substitution.

Does the FZT948TC require a base resistor when driven by a 3.3 V microcontroller GPIO?

Yes - a series base resistor is mandatory. With V_BE(on) ≈ -870 mV and typical GPIO sink capability of 20 mA, a 120 Ω resistor limits base current to ~2.1 A (excessive), so a 1.0 kΩ resistor yields ~2.4 mA base drive, sufficient for ~150 mA collector current. For full -6 A switching, external driver stages or higher-current GPIOs with appropriate current-limiting resistors are required.

Can the FZT948TC be used in linear amplifier configurations?

Yes - its h_FE is specified from -10 mA to -20 A and V_CE(sat) remains well-defined across that range, supporting Class-A or AB linear operation. However, power dissipation must be strictly managed: at V_CE = -10 V and I_C = -300 mA, PD = 3 W exceeds its 3.0 W rating unless heatsinked, so linear use is limited to low-voltage, low-current bias or small-signal amplification with careful thermal design.