NXP Semiconductors MRF7S18125BHSR5

Overview

MRF7S18125BHSR5 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 1800–2000 MHz band. It delivers 125 W CW output at 28 V, achieves 16.5 dB power gain and 55% drain efficiency at 1930 MHz, and supports Class AB/C operation under full-band EDGE modulation.

For engineers reviewing the MRF7S18125BHSR5 datasheet, MRF7S18125BHSR5 pinout, MRF7S18125BHSR5 application, or MRF7S18125BHSR5 equivalent, key selection criteria include VSWR ruggedness (5:1 @ 125 W), ESD protection class (HBM 1B), thermal resistance (0.35 °C/W at 71 W), spectral regrowth (-60 dBc @ 400 kHz), and internal input/output matching for simplified PA design.

Technical Context

This device employs a laterally diffused MOS (LDMOS) structure optimized for high-efficiency, high-linearity RF power amplification in cellular infrastructure. Its internally matched 50 Ω input and output enable direct integration into broadband PA stages without external matching networks across 1930–1990 MHz.

It operates with fixed 28 V DC supply and 1100 mA quiescent drain current, supporting both continuous-wave and pulsed-CW modes (e.g., 10 μs on, 10% duty cycle). Thermal design is enabled by low R_θJC (0.35 °C/W) and rated junction temperature of 225 °C, validated per AN1955 thermal methodology.

Key Specifications

Pinout & Package

Package: NI-780S (Case 465A-06, Style 1), flange-mounted ceramic/metal hermetic package with solderable base for high-power thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF7S18125BHSR5, AFM905S trades 15 W output headroom for 1 dB extra gain and relaxed thermal design, while MRF7S18125N offers identical RF performance in a physically larger package that increases board area by 42% but eases heatsink mounting.

Availability

MRF7S18125BHSR5 is available at Aetrix Electronics and suitable for macrocell base stations, remote radio heads, and multi-carrier amplifiers requiring stable component supply, long-lifecycle support, and traceable sourcing for telecom infrastructure programs.

Supply support for MRF7S18125BHSR5 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 from its Freescale acquisition.

The MRF7S series was developed specifically for high-reliability, high-efficiency cellular infrastructure amplifiers, targeting GSM, EDGE, and early LTE base station applications where ruggedness, linearity, and thermal stability are critical.

FAQ

What is the maximum safe operating voltage for MRF7S18125BHSR5?

The MRF7S18125BHSR5 has a maximum drain-source voltage rating of +65 Vdc. However, its specified operating voltage is 32 Vdc, and Freescale's characterization data and recommended bias conditions are strictly defined at 28 Vdc. Operating above 28 Vdc requires full thermal and reliability validation; the device is not characterized or guaranteed for sustained operation beyond this voltage.

Does MRF7S18125BHSR5 require external input/output matching networks?

No. The MRF7S18125BHSR5 is internally matched for 50 Ω systems across its full 1930–1990 MHz operating band, as confirmed in Table 4 and Figure 17 of the datasheet. External matching is unnecessary for standard PA designs, though narrowband optimization may use minimal tuning stubs for peak efficiency.

How does the thermal resistance of MRF7S18125BHSR5 compare between power levels?

The MRF7S18125BHSR5 specifies two thermal resistance values: 0.31 °C/W at 125 W CW (case temp 81°C) and 0.35 °C/W at 71 W CW (same case temp). This reflects improved heat spreading efficiency at higher power dissipation, enabling tighter thermal design margins in high-output applications.

Can MRF7S18125BHSR5 be used in Doherty amplifier configurations?

Yes. The MRF7S18125BHSR5's symmetric large-signal impedance characteristics (Z_source and Z_load provided in Figure 17), wide VSWR tolerance, and stable gain flatness (1.02 dB over 60 MHz) make it suitable for Doherty main and auxiliary amplifier roles, particularly in dual-band GSM/EDGE implementations.

What is the gate quiescent voltage requirement for MRF7S18125BHSR5?

The MRF7S18125BHSR5 requires a fixture gate quiescent voltage (V_GG(Q)) of 4–7 Vdc, with a typical value of 5.3 Vdc at V_DD = 28 Vdc and I_DQ = 1100 mA. This is achieved using a resistive divider network per Figure 1; the intrinsic gate threshold voltage (V_GS(th)) is 1.2–2.7 Vdc, but the applied gate bias must account for divider losses.