NXP Semiconductors MRF7S18125AHSR5

Overview

MRF7S18125AHSR5 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 in cellular infrastructure transmitters.

For engineers reviewing the MRF7S18125AHSR5 datasheet, MRF7S18125AHSR5 pinout, MRF7S18125AHSR5 application, or MRF7S18125AHSR5 equivalent, this device is selected for high-efficiency, high-linearity RF power amplification where VSWR tolerance, thermal robustness, and integrated ESD protection are critical in macrocell BTS designs.

Technical Context

This LDMOS transistor operates with a 28 V DC supply and 1100 mA quiescent drain current, optimized for narrowband and wideband EDGE modulation across the 1805–1880 MHz band. Its internally matched input/output impedances simplify matching network design, and it sustains 5:1 VSWR at 125 W CW without damage.

The device features series-equivalent large-signal impedance characterization, RoHS-compliant NI-780S packaging, and thermal resistance of 0.34 °C/W (at 71 W CW). Junction temperature is rated to 225 °C, with case operating limit at 150 °C and storage range from −65 to +150 °C.

Key Specifications

Pinout & Package

Package: NI-780S (Case 465A-06, Style 1), hermetically sealed ceramic/metal flange-mount package with solderable baseplate 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 MRF7S18125AHSR5, the AHR3 variant trades slightly better thermal resistance for larger size and lower VSWR margin, while AFM905S shifts focus toward LTE bandwidth and sacrifices GSM EDGE linearity-making MRF7S18125AHSR5 the optimal choice for dedicated, high-reliability GSM/EDGE macrocell PA upgrades.

Availability

MRF7S18125AHSR5 is available at Aetrix Electronics and suitable for macrocell base station transmitters, GSM EDGE infrastructure amplifiers, and thermally constrained outdoor wireless equipment requiring stable component supply and long lifecycle support.

Supply support for MRF7S18125AHSR5 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 specializing in secure connectivity solutions for automotive, industrial, and communications markets, with deep heritage in RF power technology from its Freescale acquisition.

The MRF7S18125AHSR5 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 frequency bands.

FAQ

What is the maximum continuous drain current rating for MRF7S18125AHSR5?

The MRF7S18125AHSR5 is rated for 1100 mA quiescent drain current (IDQ) under typical GSM operating conditions (VDD = 28 V, Pout = 125 W CW). Absolute maximum ratings do not specify a standalone ID(max) value; instead, safe operation is defined by junction temperature limits (TJ ≤ 225 °C) and thermal resistance (RθJC = 0.34 °C/W). The MRF7S18125AHSR5 must be operated within its safe operating area (SOA) curves, which constrain simultaneous voltage, current, and pulse conditions.

Does MRF7S18125AHSR5 require external gate protection circuitry?

No, the MRF7S18125AHSR5 integrates ESD protection meeting HBM Class 1B, MM Class A, and CDM Class IV standards per JESD22-A114/A115/C101. This eliminates the need for external gate protection diodes in standard handling and operational environments. However, proper PCB layout-such as short, low-inductance gate traces and local decoupling-is still required to maintain stability and prevent oscillation, especially under high VSWR conditions where reflected energy may stress the gate.

Can MRF7S18125AHSR5 be used in Class C mode for GSM applications?

Yes, the MRF7S18125AHSR5 is explicitly characterized and qualified for both Class AB and Class C operation in GSM base station applications. Its lateral LDMOS structure and internal matching support efficient saturated operation at 125 W CW with 17 dB power gain and 55% drain efficiency. Class C use requires appropriate harmonic termination in the output matching network and careful bias tuning (e.g., reduced IDQ) to achieve optimal efficiency while maintaining spectral compliance per 3GPP TS 45.005.

What is the P1dB compression point of MRF7S18125AHSR5 under typical conditions?

The MRF7S18125AHSR5 delivers a typical P1dB output power of 140 W CW at VDD = 28 V, IDQ = 1100 mA, and f = 1880 MHz in Freescale's test fixture. This corresponds to an input power of approximately 51.6 dBm (144.6 W), confirmed in Figure 8 of the datasheet. The P1dB remains stable across temperature (−30°C to +85°C) with a variation of only 0.01 dBm/°C, making the MRF7S18125AHSR5 highly predictable in production PA designs.

How does MRF7S18125AHSR5 differ from MRF7S18125AHSR3 in packaging and thermal performance?

The MRF7S18125AHSR5 is identical to MRF7S18125AHSR3 in die, electrical specs, and pinout (NI-780S, Style 1: pins 1–DRAIN, 2–GATE, 5–SOURCE), but differs in reel packaging quantity and tape configuration. "SR5" denotes a 500-unit tape-and-reel variant (vs. SR3 = 250 units), with identical physical dimensions, thermal resistance (0.34 °C/W), and mechanical specifications per Case 465A-06 Issue H. No electrical or thermal performance difference exists between SR3 and SR5 suffixes.