NXP Semiconductors MRF8S18120HR5

Overview

MRF8S18120HR5 from NXP Semiconductors (formerly Freescale) is a laterally diffused N-channel RF power MOSFET designed for GSM and GSM EDGE base station final-stage amplification in the 1805–1880 MHz band. It delivers 72 W CW output at 28 V, achieves 18.7 dB power gain and 53.9% drain efficiency at 1880 MHz, and supports Class AB/C operation with 120 W P1dB compression point.

For engineers reviewing the MRF8S18120HR5 datasheet, MRF8S18120HR5 pinout, MRF8S18120HR5 application, or MRF8S18120HR5 equivalent, key selection criteria include VSWR ruggedness (7:1 @ 32 V), integrated ESD protection (HBM Class 2), thermal resistance (0.46 °C/W), Doherty-optimized matching, and GSM EDGE EVM performance (≤2.0% rms at 1880 MHz).

Technical Context

This device employs an enhancement-mode lateral MOSFET structure with internally matched input/output networks, enabling direct integration into 50 Ω RF systems without external impedance transformation. Its gate threshold voltage (1.2–2.7 V) and quiescent gate voltage (1.8–3.3 V) support stable Class AB biasing under temperature variation (±0.01 dB/°C gain drift).

Thermal design is enabled by a low junction-to-case thermal resistance (0.46 °C/W at 120 W CW) and maximum junction temperature rating of 225 °C. The device is characterized using series-equivalent large-signal impedance parameters and common-source S-parameters, supporting accurate load-pull modeling for Doherty amplifier architectures.

Key Specifications

Pinout & Package

Package: NI-780 (Case 465-06, Style 1), ceramic/metal flanged package with solderable baseplate and three-terminal configuration (Gate, Drain, Source). Thermal path optimized via direct metal baseplate mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF8S18120HSR5, the MRF8S18120HR5 offers identical RF specs but slightly relaxed thermal spec; versus AFM906S, it trades 2.2 dB gain for 30 W higher P1dB and 40 MHz wider bandwidth-critical for full-band GSM EDGE compliance.

Availability

MRF8S18120HR5 is available at Aetrix Electronics and suitable for macrocell base stations, GSM EDGE transmitters, Doherty carrier amplifiers, and high-VSWR resilient RF power applications requiring stable component supply across multi-year production cycles.

Supply support for MRF8S18120HR5 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 is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and communications markets, with deep heritage in RF power technology inherited from Freescale.

The MRF8S18120HR5 belongs to NXP's LDMOS RF power transistor family, engineered specifically for high-efficiency, high-linearity cellular infrastructure amplifiers operating in licensed sub-2 GHz bands.

FAQ

What is the maximum continuous drain voltage rating for the MRF8S18120HR5?

The MRF8S18120HR5 has a maximum drain-source voltage rating of +65 Vdc, with a minimum rating of –0.5 Vdc. This allows safe operation under transient conditions such as load mismatch or switching surges in base station power amplifier stages. The device is rated for continuous operation at 32 Vdc drain supply, and its 7:1 VSWR ruggedness is validated at 32 Vdc and 150 W CW output.

Does the MRF8S18120HR5 require external matching networks for 1805–1880 MHz operation?

No, the MRF8S18120HR5 is internally matched for 50 Ω systems across the full 1805–1880 MHz band. Freescale's characterization data confirms optimal source and load impedances (e.g., Zload = 2.33 – j0.26 Ω at 1840 MHz) are realized within the NI-780 package, eliminating discrete matching components in standard test fixtures and simplifying PCB layout for production designs.

What is the typical EVM performance of the MRF8S18120HR5 under GSM EDGE modulation?

The MRF8S18120HR5 achieves 1.7% rms EVM at 1840 MHz and 46 W average output power under GSM EDGE modulation, with VDD = 28 Vdc and IDQ = 800 mA. At 1880 MHz, EVM rises to 2.0% rms-still within 3GPP-compliant limits for Class A/B base station transmitters-demonstrating consistent linearity across the entire operating band.

How does the thermal resistance of the MRF8S18120HR5 compare between 72 W and 120 W operating conditions?

The MRF8S18120HR5 exhibits a junction-to-case thermal resistance of 0.47 °C/W at 72 W CW and improves marginally to 0.46 °C/W at 120 W CW (both measured at case temperature of 79°C). This near-constant RθJC reflects stable thermal conduction through the NI-780 ceramic/metal package, enabling predictable heatsink sizing across both linear and compressed operating regions.

Is the MRF8S18120HR5 pin-compatible with the MRF8S18120HSR5?

Yes, the MRF8S18120HR5 and MRF8S18120HSR5 share identical pinout, footprint, and terminal configuration (NI-780 vs. NI-780S), differing only in internal thermal interface construction. Both use the same Case 465-06 mechanical outline and are mounted identically on PCBs-no layout changes are required when substituting between these variants.