Diodes Incorporated FMMT493ATC

Overview

FMMT493ATC from Diodes Incorporated is a high-gain NPN medium-power transistor in SOT23 package, rated for 60V V_CEO, 1A continuous collector current, and 500mW power dissipation. It delivers low saturation voltage (V_CE(SAT) = 500 mV @ 1A), minimum h_FE of 300 at 250mA, and is AEC-Q101 qualified for automotive reliability. It serves as a switching element in relay drivers and DC-DC module control stages.

For engineers reviewing the FMMT493ATC datasheet, FMMT493ATC pinout, FMMT493ATC application, or FMMT493ATC equivalent, key selection criteria include verified V_CE(SAT) performance at 1A, h_FE stability across -55°C to +150°C, thermal resistance (R_θJA = 250°C/W on 15mm × 15mm FR-4), and AEC-Q101 qualification status for automotive-grade deployment.

Technical Context

This NPN bipolar junction transistor operates in linear or saturated switching mode with base-driven current control. Its design emphasizes high DC current gain (h_FE ≥ 300 @ I_C = 250mA, V_CE = 10V) and robust breakdown ratings: V_CBO = 120V, V_CEO = 60V, and V_EBO = 7V.

Thermal behavior is characterized by R_θJA = 250°C/W and R_θJL = 197°C/W under defined PCB conditions, supporting operation from -55°C to +150°C. ESD robustness includes HBM rating of 4,000V and MM ≥ 400V, meeting industrial and automotive handling requirements.

Key Specifications

Pinout & Package

Package: SOT23 (Type DN), surface-mount plastic case 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 medium-power switching applications.

Compared with ZXTN25050CFH and MMBT4401, FMMT493ATC provides superior automotive qualification, higher voltage headroom (60V), lower saturation voltage at full 1A, and verified thermal performance on standard PCBs-making it the only choice for AEC-Q101-compliant 1A switching in harsh environments.

Availability

FMMT493ATC is available at Aetrix Electronics and suitable for automotive body electronics, industrial relay interfaces, and DC-DC converter designs requiring stable component supply, AEC-Q101 compliance, and consistent 1A switching performance.

Supply support for FMMT493ATC 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 and manufacturing operations across Asia and the Americas.

The FMMT493ATC belongs to Diodes' AEC-Q101-qualified discrete transistor portfolio, engineered specifically for automotive and industrial switching applications demanding high reliability, low saturation loss, and extended temperature operation.

FAQ

What is the maximum continuous collector current for FMMT493ATC at 100°C ambient?

At T_A = 100°C, the maximum continuous collector current is derated to approximately 0.6A based on the 500mW power limit and R_θJA = 250°C/W. This assumes mounting on a 15mm × 15mm FR-4 PCB with 1 oz copper in still air. Derating curves in the datasheet confirm linear reduction from 1A at 25°C to zero at ~150°C junction temperature.

Is FMMT493ATC suitable for driving inductive loads without an external flyback diode?

No. While FMMT493ATC has robust V_CEO = 60V and I_CM = 2A, it does not integrate a flyback diode. Driving relays or solenoids requires an external reverse-biased diode (e.g., 1N4148 or MURS120) across the load to clamp inductive kickback and prevent V_CE overshoot beyond 60V.

How does the h_FE of FMMT493ATC vary with collector current and temperature?

h_FE peaks near 500 at I_C = 150mA and declines to 300 at I_C = 250mA and 20 at I_C = 1A (all at V_CE = 10V). Over temperature, typical h_FE decreases ~0.5%/°C above 25°C but remains ≥200 at 100°C and I_C = 250mA, per Figure 5 in DS33094 Rev. 4-2.

Can FMMT493ATC be used in linear amplifier configurations?

Yes, but with strict thermal and bias limitations. Its f_T = 150MHz and h_FE stability support low-noise preamplifier stages up to ~10MHz. However, linear operation at >100mW dissipation requires active heatsinking due to R_θJA = 250°C/W; most designs use it in saturated switching mode for efficiency and thermal safety.