Diodes Incorporated FMMT5179TC

Overview

FMMT5179TC from Diodes Incorporated is an NPN silicon planar high-frequency transistor in SOT-23 package, featuring f_T ≥ 900 MHz, C_cb = 1 pF, NF = 4.5 dB at 200 MHz, V_CEO = 12 V, and I_C = 50 mA - optimized for RF amplification in VHF/UHF front-end stages of wireless receivers and low-noise IF amplifiers.

For engineers reviewing the FMMT5179TC datasheet, FMMT5179TC pinout, FMMT5179TC application, or FMMT5179TC equivalent, key selection criteria include verified transition frequency performance at 5 mA/6 V, low-noise figure under 50 Ω source impedance, SOT-23 thermal derating behavior up to +150°C, and validated h_FE range (25–250) at 3 mA/1 V for bias stability in discrete gain blocks.

Technical Context

This device employs a planar epitaxial structure with minimized base-collector capacitance (C_cb = 1 pF at V_CB = 10 V) and low base resistance to support stable high-frequency operation. Its f_T spans 900–2000 MHz under standard 5 mA/6 V conditions, enabling use in narrowband 200–500 MHz amplifier designs.

The transistor exhibits low noise figure (NF = 4.5 dB at I_C = 1.5 mA, V_CE = 6 V, R_S = 50 Ω, f = 200 MHz) and moderate DC current gain (h_FE = 25–250 at I_C = 3 mA, V_CE = 1 V), making it suitable for cascode or common-emitter low-noise amplifier topologies where gain-noise trade-offs are critical.

Key Specifications

Pinout & Package

Supplied in JEDEC-standard SOT-23 (TO-236AB) plastic surface-mount package with 3-pin configuration and gull-wing leads. Thermal resistance R_θJA = 375°C/W typical; footprint compatible with automated reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBT5179, FMMT5179TC offers identical RF performance but distinct traceability and qualification documentation; versus PN2222A, it delivers >3× higher f_T, 8× lower C_cb, and 5.5 dB lower noise - essential for modern sub-GHz wireless sensor front-ends.

Availability

FMMT5179TC is available at Aetrix Electronics and suitable for FM radio front-end amplifiers, UHF remote keyless entry receivers, and ISM band sensor transceivers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for FMMT5179TC 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.

FMMT5179TC belongs to Diodes' FMMT series of high-frequency bipolar transistors, engineered specifically for low-noise, high-gain RF amplification in consumer, automotive, and industrial wireless systems operating below 1 GHz.

FAQ

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

The datasheet specifies f_T testing at I_C = 5 mA, and typical curves show peak f_T near 10 mA. Operation above 15 mA causes measurable degradation due to self-heating; for production designs, I_C ≤ 10 mA is recommended to maintain ≥900 MHz minimum f_T across temperature.

Can FMMT5179TC replace BC847B in a 2.4 GHz Wi-Fi LNA?

No - BC847B has f_T ≈ 250 MHz and C_cb ≈ 4 pF, insufficient for 2.4 GHz operation. FMMT5179TC's 900 MHz f_T also falls short of 2.4 GHz fundamental requirements; it is validated only up to 500 MHz per G_pe and f_T data. Use GaAs or RF CMOS devices for 2.4 GHz.

Is the SOT-23 package lead-free and RoHS-compliant?

Yes - Diodes Incorporated certifies FMMT5179TC as lead-free and RoHS-compliant per Directive 2011/65/EU. The SOT-23 package uses matte tin (Sn) plating on gull-wing leads, with no exemptions claimed; full compliance documentation is available via Diodes' Quality Portal.

Does the 4.5 dB noise figure apply across the full 25°C to +125°C range?

No - the 4.5 dB NF is specified only at T_amb = 25°C. Typical curves show NF increases to ~6.2 dB at +125°C due to increased thermal noise and reduced h_FE; system-level noise budgeting must account for this drift in high-temperature deployments like engine bay sensors.