NXP Semiconductors MRF21045LR3

Overview

MRF21045LR3 from Freescale Semiconductor is an N-channel enhancement-mode lateral RF power MOSFET designed for W-CDMA base station amplifiers operating at 2110–2170 MHz. It delivers 10 W average output power with 15 dB gain, 23.5% drain efficiency, and –41 dBc ACPR under two-carrier W-CDMA conditions (V_DD = 28 V, I_DQ = 500 mA). It is internally matched and rated for 45 W PEP CW operation into 5:1 VSWR.

For engineers reviewing the MRF21045LR3 datasheet, MRF21045LR3 pinout, MRF21045LR3 application, or MRF21045LR3 equivalent, key selection criteria include its 2110–2170 MHz frequency band, 28 V drain supply compatibility, 1.65 °C/W thermal resistance, RoHS-compliant NI-400 package, and verified two-tone IMD performance at 45 W PEP.

Technical Context

This device operates in Class AB for cellular infrastructure applications, using a laterally diffused MOS (LDMOS) structure optimized for linearity and thermal stability. Its internally matched 25 Ω input/output impedance simplifies external matching network design while maintaining flat insertion phase across the band.

The MRF21045LR3 features integrated ESD protection (HBM Class 1, MM Class M2), low gate threshold voltage (2–4 V), and high transconductance (typ. 3 S), enabling stable biasing and efficient drive. Its series-equivalent large-signal impedance data (e.g., Z_source = 3.12 – j3.72 Ω at 2140 MHz) supports accurate broadband amplifier synthesis.

Key Specifications

Pinout & Package

Package: NI-400 (Case 465E-04, Style 1), hermetically sealed ceramic/metal flange-mount package with solderable leads and 40 μ″ nominal gold plating. Designed for high-reliability RF power amplifier modules requiring low thermal resistance and stable RF grounding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with the MRF21045LR3, the MRFE6VP61K25H offers significantly higher power capability and bandwidth but demands full redesign, while the PD85003 provides mechanical compatibility and lower cost at the expense of gain and efficiency-making it suitable only for non-critical linearity applications.

Availability

MRF21045LR3 is available at Aetrix Electronics and suitable for W-CDMA base station development, wireless local loop (WLL) transmitter builds, and PCN/PCS cellular radio amplifier designs requiring stable component supply and long-term lifecycle support.

Supply support for MRF21045LR3 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) was a leading designer of RF power transistors for wireless infrastructure, emphasizing high-efficiency LDMOS technology and rigorous thermal characterization.

The MRF21045LR3 belongs to Freescale's MRF210xx RF power MOSFET family, engineered specifically for linear, high-reliability amplification in 3G W-CDMA base stations and related broadband cellular infrastructure applications.

FAQ

What is the maximum continuous drain power dissipation for the MRF21045LR3?

The MRF21045LR3 has a maximum total device dissipation of 105 W at case temperature (T_C) = 25°C, derating linearly at 0.60 W/°C above that temperature. This rating assumes proper heatsinking and adherence to the specified thermal resistance (R_θJC = 1.65 °C/W) to maintain junction temperature below 200°C. The MRF21045LR3 must be mounted on a thermally optimized copper baseplate or heatsink to sustain this power level reliably.

Does the MRF21045LR3 require external matching networks for 50 Ω systems?

No-the MRF21045LR3 is internally matched for both input and output to 25 Ω, enabling direct integration into standard 50 Ω RF systems with minimal external components. Its datasheet provides verified series-equivalent source and load impedances (e.g., Z_source = 3.12 – j3.72 Ω at 2140 MHz), allowing designers to implement simple, high-performance matching networks. The MRF21045LR3 achieves –12 dB input return loss and >13.5 dB gain without complex tuning.

What is the gate threshold voltage range for the MRF21045LR3?

The MRF21045LR3 has a gate threshold voltage (V_GS(th)) range of 2 V to 4 V, measured at V_DS = 10 Vdc and I_D = 100 μAdc. This low and well-defined threshold enables stable Class AB biasing with typical gate quiescent voltage (V_GS(Q)) of 3.9 V at I_DQ = 500 mA and V_DD = 28 V. The MRF21045LR3's tight V_GS(th) distribution supports consistent bias point setting across production lots.

Can the MRF21045LR3 operate safely under 5:1 VSWR conditions?

Yes-the MRF21045LR3 is explicitly rated to handle 5:1 VSWR at 28 Vdc and 2140 MHz with 45 W CW output power without degradation or failure. This ruggedness stems from its lateral MOSFET structure, integrated ESD protection, and thermal design margin. The MRF21045LR3's ability to survive high VSWR events makes it suitable for antenna-integrated base station modules where impedance mismatches may occur during deployment or environmental shifts.

Is the MRF21045LR3 still in active production or subject to end-of-life status?

The MRF21045LR3 is a lifetime buy product with last order date of 1 July 2011 and last shipment date of 30 June 2012, as documented in Freescale's official datasheet (Rev. 12, October 2008). While no longer in active production, Aetrix Electronics maintains legacy inventory and supports continued use in maintenance, repair, and obsolescence mitigation programs for deployed W-CDMA infrastructure. The MRF21045LR3 remains fully functional and qualified for its original specifications.