Diodes Incorporated FCX789ATA

Overview

FCX789ATA from Diodes Incorporated is a 25V PNP medium-power transistor in SOT89 package, rated for -3A continuous collector current and -8A peak pulse current, with V_CE(sat) < -320mV at -3A and h_FE ≥ 180 at -3A. It serves as a high-current switching or linear amplification device in automotive power management, industrial motor drivers, and DC-DC converter output stages.

For engineers reviewing the FCX789ATA datasheet, FCX789ATA pinout, FCX789ATA application, or FCX789ATA equivalent, key selection criteria include guaranteed h_FE hold-up to -6A, AEC-Q101 qualification, low thermal resistance (R_θJL = 5.31°C/W), RoHS-compliant matte tin plating, and SOT89 mechanical compatibility with 1W steady-state dissipation on 40mm×40mm PCB.

Technical Context

This PNP bipolar junction transistor operates with emitter-grounded configuration, supporting linear and saturated switching modes. Its BV_CEO = -25V and VEBO = -7V define safe operating voltage boundaries, while f_T = 100MHz enables moderate-speed switching up to ~35ns turn-on and 400ns turn-off times under specified test conditions.

Thermal design is enabled by R_θJL = 5.31°C/W (junction-to-leads) and R_θJA = 62.5°C/W on 40mm×40mm FR4 - critical for sustained -3A operation without active cooling. ESD robustness includes 4kV HBM and ≥400V MM ratings per JEDEC standards.

Key Specifications

Pinout & Package

Package: SOT89 - surface-mount, 3-lead molded plastic case with UL 94V-0 flammability rating, 0.05g weight, and matte tin-plated leads solderable per MIL-STD-202 Method 208.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX789A and MJD2955T4G, FCX789ATA uniquely balances AEC-Q101 compliance, SOT89 space efficiency, and guaranteed h_FE performance at -3A - making it optimal for automotive and space-constrained industrial switching where reliability and thermal density are prioritized over raw voltage headroom or ultra-high current.

Availability

FCX789ATA is available at Aetrix Electronics and suitable for automotive body control modules, industrial relay drivers, and DC-DC converter output stages requiring stable component supply, long-term lifecycle support, and AEC-Q101-qualified parts.

Supply support for FCX789ATA 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.

The FCX789ATA belongs to Diodes' FCX series of medium-power transistors designed specifically for AEC-Q101-compliant automotive power switching and industrial interface applications requiring robust thermal performance and precise gain control.

FAQ

What is the maximum continuous collector current for FCX789ATA at 100°C ambient?

At T_A = 100°C, FCX789ATA's maximum continuous collector current is derated to approximately -1.6A based on its 62.5°C/W R_θJA (40mm×40mm PCB) and 150°C maximum junction temperature. This assumes no forced airflow and standard FR4 board construction.

Is FCX789ATA pin-compatible with its complementary NPN type FCX688B?

Yes - FCX789ATA (PNP) and FCX688B (NPN) share identical SOT89 pinout (C-E-C-B layout), enabling direct layout reuse in push-pull or H-bridge configurations. Both feature matching thermal and electrical specifications optimized for complementary operation.

Does FCX789ATA require external base resistors in typical switching applications?

Yes - base current must be limited to avoid exceeding I_B = -100mA (for -3A I_C). A typical 1.2kΩ resistor from 5V MCU GPIO yields ~3.3mA I_B, insufficient for full saturation; 100Ω is recommended to deliver ~40mA I_B and ensure V_CE(sat) remains below -320mV.

Can FCX789ATA be used in linear regulator applications with >1W power dissipation?

Yes - with proper PCB copper area (≥40mm×40mm 1oz Cu), FCX789ATA sustains 1W continuously at T_A = 25°C. At higher ambient temperatures or smaller copper areas, derating applies; its R_θJL = 5.31°C/W allows effective heat transfer directly through the collector lead to large copper pours.