NXP Semiconductors MRF7S18125AHR5

Overview

MRF7S18125AHR5 from NXP Semiconductors (formerly Freescale) is an N-channel enhancement-mode lateral RF power MOSFET designed for GSM and GSM EDGE base station final-stage amplification in the 1805–1880 MHz band. It delivers 125 W CW output at 28 V, achieves 17 dB power gain and 55% drain efficiency under GSM conditions, and supports Class AB/C operation with 5:1 VSWR tolerance at 125 W CW.

For engineers reviewing the MRF7S18125AHR5 datasheet, MRF7S18125AHR5 pinout, MRF7S18125AHR5 application, or MRF7S18125AHR5 equivalent, this device is selected for high-efficiency, high-linearity cellular infrastructure PA stages where thermal robustness, ESD protection, and broadband impedance matching are critical design requirements.

Technical Context

This LDMOS transistor operates with a fixed 28 V drain supply and 1100 mA quiescent drain current, enabling stable large-signal performance across the 1805–1880 MHz band. Its internally matched input and output impedances simplify external network design, while series-equivalent large-signal Z-parameters support accurate load-pull modeling.

The device features integrated ESD protection rated to Human Body Model Class 1B, Machine Model Class A, and Charge Device Model Class IV. Thermal resistance from junction to case is 0.31 °C/W at 125 W CW, supporting reliable operation up to 150 °C case temperature and 225 °C junction temperature.

Key Specifications

Pinout & Package

Package: NI-780 (Case 465-06, Style 1), hermetically sealed ceramic/metal flange-mount package with integral heat slug. Dimensions: 34.16 mm × 9.91 mm × 4.32 mm (L×W×H); flange-mounted for direct thermal coupling to heatsink.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RF power MOSFET applications.

Compared with MRF7S18125AHR5, the MRF7S18125AHSR3 offers identical RF performance in a reduced footprint, while the PD85018L provides comparable output power but demands layout and bias circuit changes due to differing pin configuration and parasitic capacitance.

Availability

MRF7S18125AHR5 is available at Aetrix Electronics and suitable for GSM base station transmitters, GSM EDGE macrocell PAs, multi-carrier DAS head-ends, remote radio heads, and field-deployable cellular infrastructure requiring stable component supply and long-lifecycle support.

Supply support for MRF7S18125AHR5 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

NXP Semiconductors acquired Freescale Semiconductor in 2015 and maintains its RF Power portfolio for cellular infrastructure, broadcast, and industrial heating applications.

The MRF7S18125AHR5 belongs to the MRF7S family of high-efficiency LDMOS transistors engineered specifically for 1800–2000 MHz GSM/GSM EDGE base station final amplifiers demanding high linearity, thermal resilience, and VSWR ruggedness.

FAQ

What is the maximum continuous drain voltage rating for the MRF7S18125AHR5?

The MRF7S18125AHR5 has a maximum drain-source voltage rating (VDSS) of +65 Vdc. This rating applies under static off-state conditions; during RF operation, the device must be operated within the safe operating area defined by VDD = 28 Vdc and peak RF voltage swing constrained by the 5:1 VSWR survivability specification at 125 W CW. Exceeding 65 Vdc risks permanent breakdown.

Does the MRF7S18125AHR5 require external gate protection diodes?

No, the MRF7S18125AHR5 incorporates integrated ESD protection meeting HBM Class 1B (≥1.5 kV), Machine Model Class A, and CDM Class IV standards. External gate protection diodes are not required in standard GSM/GSM EDGE PA designs, provided PCB layout follows Freescale's recommended grounding and trace routing practices from AN1955 and EB212.

What is the typical gate quiescent voltage (VGS(Q)) for the MRF7S18125AHR5 at 28 V operation?

The typical gate quiescent voltage (VGS(Q)) for the MRF7S18125AHR5 is 2.7 Vdc when biased at VDD = 28 Vdc and IDQ = 1100 mA. This value is measured directly at the gate terminal under DC conditions; the fixture gate voltage (VGG(Q)) is higher (5.3 Vdc typical) due to an on-board resistive divider, but VGS(Q) reflects the actual device-level control voltage.

Can the MRF7S18125AHR5 be used in Class C amplifier configurations?

Yes, the MRF7S18125AHR5 is explicitly characterized for both Class AB and Class C operation in GSM and GSM EDGE base station applications. Its lateral LDMOS structure and optimized doping profile support efficient switching behavior in Class C, particularly for constant-envelope GSM GMSK modulation where harmonic content is managed by output filtering.

What thermal resistance value should be used for heatsink design with the MRF7S18125AHR5?

For heatsink thermal design, use RθJC = 0.31 °C/W - the junction-to-case thermal resistance measured at 125 W CW output and 80 °C case temperature. This value assumes proper mounting torque (15–20 in·lb), thermal interface material (e.g., 0.5 mm thick, 1.5 W/m·K conductivity), and full flange contact. Derating is required above 125 W CW per Freescale's MTTF calculator.