NXP Semiconductors MRF8S18120HSR3

Overview

MRF8S18120HSR3 from NXP Semiconductors (formerly Freescale) is a laterally diffused metal-oxide-semiconductor (LDMOS) RF power transistor 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 53.9% drain efficiency at 1880 MHz, and supports 120 W P1dB compression under CW conditions - deployed in macrocell and distributed antenna system (DAS) transmitters.

For engineers reviewing the MRF8S18120HSR3 datasheet, MRF8S18120HSR3 pinout, MRF8S18120HSR3 application, or MRF8S18120HSR3 equivalent, key selection criteria include its 7:1 VSWR ruggedness rating at 32 Vdc, integrated ESD protection (HBM Class 2), internally matched 50 Ω input/output, and Doherty-optimized gate biasing for high-efficiency envelope tracking architectures.

Technical Context

This N-channel enhancement-mode LDMOS device operates in Class AB or Class C with fixed-quiescent current (IDQ = 800 mA) and supports both continuous-wave and EDGE-modulated signals. Its series-equivalent large-signal impedance parameters are fully characterized across 1805–1880 MHz, enabling accurate load-pull design of matching networks for peak P1dB and spectral regrowth control.

The transistor features a negative gate-source voltage range extended to –6.0 Vdc for stable Class C operation, RoHS-compliant packaging in NI-780S (CASE 465A-06), and thermal resistance RθJC of 0.46 °C/W at 120 W CW - validated under junction temperature limits up to 225 °C and case temperature up to 150 °C.

Key Specifications

Pinout & Package

Package: NI-780S (CASE 465A-06), flanged ceramic/metal hermetic package with solderable baseplate and three-terminal configuration (Gate, Drain, Source). Dimensions per Freescale Doc. MRF8S18120H Rev. 1, p. 9–10.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF8S18120HSR3, the HR3 variant shares identical RF performance but demands mechanical redesign due to flange differences, while AFM905S trades 30 W of CW headroom for improved linearity and lower IMD - making it a functional alternative only in non-power-limited EDGE deployments.

Availability

MRF8S18120HSR3 is available at Aetrix Electronics and suitable for macrocell base stations, distributed antenna systems, Doherty amplifier modules, and multi-carrier GSM/EDGE transmitters requiring stable component supply across extended product lifecycles.

Supply support for MRF8S18120HSR3 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 continues to support its RF power portfolio with full documentation, modeling tools, and application engineering resources.

The MRF8S18120HSR3 belongs to NXP's LDMOS RF power transistor family, engineered specifically for cellular infrastructure applications demanding high efficiency, ruggedness, and broadband linearity in 700 MHz–3.8 GHz bands.

FAQ

What is the maximum drain-source voltage rating for the MRF8S18120HSR3?

The MRF8S18120HSR3 has a maximum drain-source voltage (VDSS) rating of +65 Vdc and –0.5 Vdc. This rating is specified in Table 1 of the Freescale MRF8S18120H datasheet Rev. 1 and defines the absolute limit for safe DC biasing - operation beyond this risks irreversible breakdown. The device is routinely tested at 32 Vdc operating voltage with 7:1 VSWR tolerance, confirming robustness well within its VDSS margin.

Does the MRF8S18120HSR3 require external input/output matching networks?

No, the MRF8S18120HSR3 is internally matched for 50 Ω operation on both input and output, as confirmed in the "Features" section and Functional Tests footnote (3) of the datasheet. While external harmonic filtering or narrowband tuning may be added for specific system requirements, the baseline design operates directly into 50 Ω loads without discrete matching components - significantly simplifying PCB layout and reducing insertion loss.

What is the thermal resistance junction-to-case (RθJC) for the MRF8S18120HSR3 at full power?

The MRF8S18120HSR3 exhibits RθJC = 0.46 °C/W when operating at 120 W CW, 28 Vdc, and IDQ = 800 mA, per Table 2 of the datasheet. This value is measured at case temperature TC = 79°C and reflects the device's ability to transfer heat efficiently from the silicon die to the heatsink interface - enabling compact thermal designs with predictable junction temperature rise under sustained high-power conditions.

Can the MRF8S18120HSR3 be used in Class C mode for GSM applications?

Yes, the MRF8S18120HSR3 supports Class C operation for GSM, enabled by its extended negative gate-source voltage range (–6.0 Vdc), as explicitly stated in the "Features" list. This allows deeper cutoff biasing to maximize efficiency in constant-envelope GSM modulation, where linearity is not required - achieving up to 53.9% drain efficiency at 1880 MHz in Class AB and higher in optimized Class C configurations.

Is the MRF8S18120HSR3 RoHS compliant and lead-free?

Yes, the MRF8S18120HSR3 is RoHS compliant, as confirmed in the "Features" section of the Freescale MRF8S18120H datasheet Rev. 1. It meets EU Directive 2011/65/EU requirements and contains no lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE). The NI-780S package uses lead-free solderable terminations and complies with JEDEC J-STD-020 moisture sensitivity level (MSL) standards.