NXP Semiconductors MRF7S18125AHR3

Overview

MRF7S18125AHR3 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 1805–1880 MHz. It delivers 125 W CW output at 28 V, achieves 17 dB power gain and 55% drain efficiency in GSM mode, and supports Class AB/C operation with 5:1 VSWR tolerance at 125 W.

For engineers reviewing the MRF7S18125AHR3 datasheet, MRF7S18125AHR3 pinout, MRF7S18125AHR3 application, or MRF7S18125AHR3 equivalent, key selection criteria include its 1805–1880 MHz bandwidth, 140 W P1dB compression point, integrated ESD protection (HBM Class 1B), NI-780 package with drain-gate-source terminal assignment, and thermal resistance of 0.31 °C/W at 125 W CW.

Technical Context

This device employs a laterally diffused MOS (LDMOS) structure optimized for high-efficiency, high-linearity cellular infrastructure amplification. Its internally matched input and output enable direct integration into 50 Ω systems without external matching networks, and it operates with fixed 28 V DC supply and 1100 mA quiescent drain current.

The MRF7S18125AHR3 is characterized using series-equivalent large-signal impedance parameters (e.g., Z_source = 1.18 − j2.66 Ω, Z_load = 1.34 − j2.02 Ω at 1840 MHz), supporting precise load-pull design. It sustains junction temperatures up to 225 °C and features RoHS-compliant packaging in tape-and-reel (250 units per 56 mm, 13-inch reel).

Key Specifications

Pinout & Package

Package: NI-780 (Case 465-06, Style 1), ceramic/metal hermetic package with flange-mount thermal interface. Dimensions: 33.91–34.16 mm × 9.65–9.91 mm × 3.18–4.32 mm (L × W × H), flange thickness 0.057–0.067 inch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NXP MRFE6VP61K25HR5 and Qorvo QPD1025, the MRF7S18125AHR3 offers optimal balance of proven LDMOS reliability, fully integrated matching, and cost-effective manufacturability for dedicated GSM/EDGE macrocell deployments - especially where legacy design reuse and simplified qualification are priorities.

Availability

MRF7S18125AHR3 is available at Aetrix Electronics and suitable for GSM macrocell transmitters, EDGE base station power amplifiers, multi-carrier DAS nodes, and remote radio heads requiring stable component supply and long-term lifecycle support.

Supply support for MRF7S18125AHR3 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 pioneer in RF power LDMOS technology, specializing in high-reliability semiconductor solutions for wireless infrastructure.

The MRF7S18125AHR3 belongs to Freescale's MRF7S family of RF power transistors, engineered specifically for high-efficiency, high-linearity amplification in cellular base stations operating in the 1.8–2.2 GHz bands.

FAQ

What is the maximum continuous drain current rating for the MRF7S18125AHR3?

The MRF7S18125AHR3 does not specify a maximum continuous drain current (I_D) rating independently; instead, its safe operating area is defined by V_DD = 28 V, P_out = 125 W CW, and T_C = 80 °C. Under these conditions, typical I_DQ = 1100 mA, and peak pulsed current reaches ~13.5 A at P1dB. The absolute maximum V_DSS = +65 Vdc and T_J = 225 °C govern electrical and thermal limits-not current alone.

Does the MRF7S18125AHR3 require external matching components in a 50 Ω system?

No - the MRF7S18125AHR3 is internally matched for 50 Ω operation across 1805–1880 MHz, as confirmed in Table 4 footnote "Part internally matched both on input and output." Freescale's test circuit (Figure 1) uses only DC blocking and bypass capacitors; no series/shunt resonators or transmission-line transformers are needed for fundamental-band operation.

What is the gate threshold voltage range for the MRF7S18125AHR3?

The gate threshold voltage (V_GS(th)) for the MRF7S18125AHR3 is specified as 1.2 V (min) to 2.7 V (max), measured at V_DS = 10 Vdc and I_D = 316 μAdc (Table 4). This range ensures consistent turn-on behavior across process variation while allowing stable Class AB biasing at V_GS(Q) = 2.7 V typical.

Can the MRF7S18125AHR3 be used in Class C mode for GSM applications?

Yes - the MRF7S18125AHR3 is explicitly qualified for both Class AB and Class C operation in GSM and GSM EDGE base station applications (first paragraph of datasheet). Its high gain, low distortion, and 5:1 VSWR tolerance make it suitable for saturated Class C operation where efficiency is prioritized over linearity, such as in constant-envelope GMSK transmission.

What is the thermal resistance junction-to-case (R_θJC) for the MRF7S18125AHR3 at 125 W CW?

The thermal resistance junction-to-case (R_θJC) for the MRF7S18125AHR3 is 0.31 °C/W when operated at 125 W CW with case temperature maintained at 80 °C (Table 2). This value assumes proper mounting to a flat, smooth heatsink with recommended torque and thermal interface material, and is validated per AN1955 methodology.