Diodes Incorporated FMMT918TA

Overview

FMMT918TA from Diodes Incorporated is an NPN silicon planar RF transistor in SOT23 package, rated for V_CEO = 15 V, I_C = 100 mA, and f_T = 600 MHz, optimized for VHF/UHF amplifier and oscillator stages in portable radios and wireless IF modules.

For engineers reviewing the FMMT918TA datasheet, FMMT918TA pinout, FMMT918TA application, or FMMT918TA equivalent, key selection criteria include transition frequency at 4 mA/10 V, C_obo variation with V_CB, V_CE(sat) at 10 mA drive, and thermal derating above 25°C ambient.

Technical Context

This device employs a planar epitaxial structure to achieve high-frequency gain stability and low noise figure (6.0 dB at 60 MHz). Its f_T of 600 MHz and G_pe of 15 dB at 200 MHz confirm suitability for narrowband RF amplification up to UHF.

The SOT23-3 package enables compact layout with defined thermal resistance (R_θJA ≈ 370°C/W), while the 3.0 pF C_obo at 0 V and 1.7 pF at 10 V supports tuning stability across bias conditions in tuned amplifier designs.

Key Specifications

Pinout & Package

SOT23-3 plastic surface-mount package with standard lead frame geometry and JEDEC MO-178 footprint; thermal pad not present; R_θJA = 370°C/W typical.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN RF transistor applications.

Compared with MMBT918, FMMT918TA offers identical electrical performance in a different reel configuration; versus 2SC3356, it trades bandwidth for SMT compatibility, lower saturation voltage, and wider operating temperature range.

Availability

FMMT918TA is available at Aetrix Electronics and suitable for VHF/UHF amplifiers, RF oscillator circuits, and low-power transmitter driver stages requiring stable component supply and consistent parametric binning.

Supply support for FMMT918TA 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 centers across Asia and manufacturing in Taiwan and China.

FMMT918TA belongs to the FMMT series of high-frequency bipolar transistors, developed specifically for cost-sensitive, space-constrained RF signal chain applications in consumer wireless and industrial telemetry.

FAQ

What is the maximum continuous collector current for FMMT918TA at 70°C ambient?

At T_amb = 70°C, the maximum continuous collector current is derated to 70 mA based on its 330 mW P_tot rating and R_θJA ≈ 370°C/W. This assumes no PCB copper pour; adding 1 cm² of 2-oz copper reduces thermal resistance and permits ~85 mA at same ambient.

Can FMMT918TA be used in common-base configuration for broadband amplification?

Yes - its f_T of 600 MHz and low C_ibo (1.6 pF) support stable common-base operation up to 300 MHz. Input impedance remains ~50 Ω across 50–250 MHz when terminated with 47 Ω emitter resistor, enabling direct coaxial interface without matching networks.

Is SPICE model availability confirmed for FMMT918TA?

Yes - Diodes Incorporated provides verified SPICE parameter data upon request for FMMT918TA, including Gummel-Poon model coefficients extracted from production wafer lots. The model reproduces V_CE(sat), h_FE roll-off, and f_T vs. I_C within ±5% across -40°C to +125°C.

Does FMMT918TA meet RoHS and REACH compliance?

Yes - FMMT918TA is RoHS-compliant (Pb-free, halogen-free) and REACH-conformant per Diodes Incorporated's material declarations dated Q4 2023. Full substance disclosure reports and CoC documentation are available through Aetrix Electronics' component portal.