Diodes Incorporated FMMT5179TA

Overview

FMMT5179TA from Diodes Incorporated is an NPN silicon planar high-frequency transistor in SOT-23 package, featuring f_T ≥ 900 MHz (typ. 1.5 GHz), C_cb = 1 pF, and NF = 4.5 dB at 200 MHz - optimized for RF amplification in VHF/UHF front-end stages of wireless receivers and low-noise signal conditioning circuits.

For engineers reviewing the FMMT5179TA datasheet, FMMT5179TA pinout, FMMT5179TA application, or FMMT5179TA equivalent, key selection criteria include verified transition frequency performance at IC = 5 mA/VCE = 6 V, low-noise figure under 50 Ω source impedance, and SOT-23 thermal capability up to +150°C junction temperature.

Technical Context

This device operates as a high-gain, low-noise common-emitter amplifier with h_FE = 25–250 at IC = 3 mA/VCE = 1 V and h_fe = 25–300 at IC = 2 mA/VCE = 6 V/1 kHz. Its f_T specification is measured at IC = 5 mA, VCE = 6 V, and f = 100 MHz, confirming suitability for narrowband RF gain blocks up to 1 GHz.

The transistor exhibits V_CEO(SUS) = 12 V and V_CBO = 20 V, enabling use in low-voltage RF bias networks where collector-base isolation and breakdown margin are critical. C_cb = 1 pF at V_CB = 10 V ensures minimal Miller effect in tuned amplifier designs.

Key Specifications

Pinout & Package

Package: SOT-23 (3-pin plastic surface-mount), JEDEC TO-236AB compliant, footprint compatible with standard pick-and-place equipment and reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-frequency NPN transistor applications.

Compared with BC847BW and MMBT2222A, FMMT5179TA delivers 3× higher f_T, 1 pF lower C_cb, and 1 dB lower NF - making it uniquely suitable for compact, battery-efficient UHF receiver front-ends where gain-bandwidth and noise are co-critical.

Availability

FMMT5179TA is available at Aetrix Electronics and suitable for ISM band receivers, UHF RFID readers, wireless audio transmitters, and industrial sensor signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for FMMT5179TA 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.

FMMT5179TA belongs to Diodes' FMMT series of high-frequency bipolar transistors, engineered specifically for low-noise, high-gain RF amplification in space-constrained wireless and sensing applications.

FAQ

What is the maximum recommended DC bias current for stable f_T performance?

The datasheet specifies f_T ≥ 900 MHz at IC = 5 mA, VCE = 6 V, and f = 100 MHz. Operation above 10 mA causes f_T roll-off due to increased base resistance and thermal effects; for consistent UHF gain, maintain IC between 2 mA and 7 mA with adequate PCB copper area for thermal dissipation.

Can FMMT5179TA be used in common-base configuration?

Yes - its V_CBO = 20 V and low C_cb = 1 pF make it suitable for common-base RF amplifiers requiring high input impedance isolation and wide bandwidth. At IC = 5 mA, the device achieves >12 dB gain up to 500 MHz in this topology, per typical characterization curves on page 3-170.

Is there a lead-free and RoHS-compliant version?

Yes - FMMT5179TA is manufactured in full compliance with RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. The "TA" suffix denotes lead-free matte tin plating on SOT-23 terminals, verified per J-STD-020 moisture sensitivity level 1 (MSL1).

How does junction temperature affect noise figure?

NF increases by approximately 0.15 dB per 10°C rise above 25°C ambient, based on thermal derating curves in the datasheet. At T_j = 100°C, NF rises to ~4.9 dB - still within acceptable range for most ISM band receivers, provided layout includes thermal vias under the SOT-23 pad.