NXP Semiconductors MRF7S18125BHR3

Overview

MRF7S18125BHR3 from Freescale Semiconductor is an N-channel enhancement-mode lateral RF power MOSFET designed for GSM and GSM EDGE base station final-stage amplification at 1800–2000 MHz. It delivers 125 W CW output at 28 V, 1930 MHz with 16.5 dB power gain and 55% drain efficiency in Class AB operation.

For engineers reviewing the MRF7S18125BHR3 datasheet, MRF7S18125BHR3 pinout, MRF7S18125BHR3 application, or MRF7S18125BHR3 equivalent, this device is selected for high-efficiency, high-power cellular infrastructure amplifiers requiring robust VSWR tolerance, low EVM, and stable thermal performance up to 225°C junction temperature.

Technical Context

This RF power transistor operates as a single-ended, internally matched amplifier optimized for 1930–1990 MHz bandwidth. Its lateral LDMOS structure enables high peak power handling (140 W P1dB), integrated ESD protection (HBM Class 1B), and series-equivalent large-signal impedance characterization for precise matching network design.

The device supports both Class AB and Class C operation under GSM and EDGE modulation schemes. Thermal resistance is specified at 0.31 °C/W (125 W CW, TC = 81°C), and it sustains 5:1 VSWR at 1960 MHz without damage-critical for deployed base station reliability.

Key Specifications

Pinout & Package

Package: NI-780 (Case 465-06, Style 1), flange-mounted ceramic/metal hermetic package with integral heat sink interface. Dimensions: 34.16 × 9.91 × 4.32 mm (L × W × H), RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF7S18125BHR3, the MRF7S18125BHSR3 offers identical RF performance in a reduced-footprint package, while the PD57018-E trades ESD protection and VSWR ruggedness for alternative sourcing-making MRF7S18125BHR3 optimal for mission-critical macrocell deployments demanding proven field reliability.

Availability

MRF7S18125BHR3 is available at Aetrix Electronics and suitable for GSM macrocell base stations, EDGE remote radio heads, multi-carrier amplifiers, and reconfigurable cellular infrastructure requiring stable component supply and long-term lifecycle support.

Supply support for MRF7S18125BHR3 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

Freescale Semiconductor (now part of NXP Semiconductors) is a global leader in RF power solutions for wireless infrastructure, automotive radar, and industrial heating applications.

The MRF7S18125BHR3 belongs to Freescale's MRF7S family of laterally diffused MOSFETs, engineered specifically for high-efficiency, high-linearity cellular base station amplifiers operating in licensed sub-2 GHz bands.

FAQ

What is the maximum junction temperature rating for the MRF7S18125BHR3?

The MRF7S18125BHR3 has a maximum operating junction temperature (TJ) of 225°C, as specified in Table 1 of its datasheet. This rating enables reliable operation in thermally demanding outdoor base station enclosures. The device's thermal resistance (RθJC) is 0.31 °C/W at 125 W CW, allowing accurate junction temperature estimation during thermal design. Engineers must ensure heatsink interface and ambient conditions maintain TJ ≤ 225°C for MTTF compliance.

Does the MRF7S18125BHR3 require external matching networks?

Yes, the MRF7S18125BHR3 requires external input and output matching networks despite being internally matched. "Internally matched" refers to on-die impedance transformation that simplifies-but does not eliminate-external tuning. The datasheet provides series-equivalent source and load impedances (e.g., Zsource = 1.13 − j3.06 Ω at 1960 MHz) to guide discrete or microstrip network design. Full 50 Ω system integration still depends on external components like those listed in Table 5 of the MRF7S18125BHR3 test circuit.

What is the ESD protection level of the MRF7S18125BHR3?

The MRF7S18125BHR3 features integrated ESD protection rated per industry standards: Human Body Model (HBM) Class 1B (≥500 V), Machine Model (MM) Class A, and Charge Device Model (CDM) Class IV. These ratings are verified per JESD22-A114, EIA/JESD22-A115, and JESD22-C101, respectively. This eliminates the need for external ESD diodes in most base station PA layouts, reducing bill-of-materials count and PCB area while maintaining robust handling during assembly and field service.

Can the MRF7S18125BHR3 operate in Class C mode?

Yes, the MRF7S18125BHR3 is explicitly characterized for both Class AB and Class C operation across typical cellular base station modulations, including GSM and GSM EDGE. In Class C, it achieves higher efficiency at the expense of linearity-suitable for constant-envelope signals. The datasheet confirms this capability in the opening application description and provides relevant performance metrics (e.g., drain efficiency, gain) under both bias conditions. Designers must adjust gate bias and output tuning accordingly for each mode.

What is the meaning of the 'R3' suffix in MRF7S18125BHR3?

The 'R3' suffix in MRF7S18125BHR3 indicates tape-and-reel packaging: 250 units per 56 mm width, 13-inch diameter reel. This format supports automated surface-mount assembly in high-volume RF power amplifier module manufacturing. The R3 designation is distinct from the 'HSR3' variant (MRF7S18125BHSR3), which uses the smaller NI-780S package but shares the same R3 reel configuration. Both variants are RoHS compliant and intended for SMT reflow processes.