NXP Semiconductors MRF7S21170HSR3

Overview

MRF7S21170HSR3 from NXP Semiconductors (formerly Freescale) is a laterally diffused N-channel enhancement-mode RF power MOSFET designed for high-efficiency, high-linearity W-CDMA and CDMA base station amplifier stages operating at 2110–2170 MHz. It delivers 50 W average output power at 28 V with 16 dB power gain and 31% drain efficiency under single-carrier W-CDMA conditions, and supports Doherty configurations in macrocell infrastructure.

For engineers reviewing the MRF7S21170HSR3 datasheet, MRF7S21170HSR3 pinout, MRF7S21170HSR3 application, or MRF7S21170HSR3 equivalent, key selection criteria include its 225°C junction temperature rating, 5:1 VSWR ruggedness at 32 V, 100% PAR-tested 170 W CW P1dB, integrated ESD protection (HBM Class 1A), and internal input/output matching optimized for 50 Ω systems.

Technical Context

This device employs a silicon LDMOS process with series-equivalent large-signal impedance characterization across 2060–2220 MHz, enabling precise load-pull design for broadband W-CDMA operation. Its gate structure supports extended negative V_GS range for stable Class C and Doherty peaking-stage biasing.

The MRF7S21170HSR3 features internally matched 50 Ω input and output ports, characterized with Z_source ≈ 4.4 – j9.4 Ω and Z_load ≈ 0.92 – j2.76 Ω at 2140 MHz under 50 W avg. W-CDMA conditions - eliminating external matching networks in many reference designs.

Key Specifications

Pinout & Package

Package: NI-880 (Case 465B-04), flanged ceramic/metal overmolded package with solderable baseplate for direct thermal mounting. Dimensions: 13.59–13.84 mm × 22.12–22.58 mm × 3.00–3.51 mm (L×W×H), 3-pin configuration (Gate, Drain, Source).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AFM906S and MRF7S21150HSR3, the MRF7S21170HSR3 uniquely balances 2110–2170 MHz band optimization, 170 W CW ruggedness, and 31% efficiency - making it the preferred choice for carrier-grade W-CDMA macrocell final stages requiring long-term reliability and thermal margin.

Availability

MRF7S21170HSR3 is available at Aetrix Electronics and suitable for macrocell base station transmitters, Doherty amplifier stages, multi-carrier W-CDMA infrastructure, and PCN-PCS radio systems requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for MRF7S21170HSR3 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 acquired Freescale's RF Power business in 2015 and continues to manufacture, qualify, and support legacy LDMOS RF power transistors for cellular infrastructure.

The MRF7S21170HSR3 belongs to the MRF7S family of high-efficiency, high-ruggedness LDMOS transistors engineered specifically for 3G/4G macrocell base station final amplifier stages operating in licensed sub-3 GHz bands.

FAQ

What is the maximum continuous drain current rating for the MRF7S21170HSR3?

The MRF7S21170HSR3 does not specify a maximum continuous drain current (I_D) rating. Instead, its safe operating area is defined by junction temperature (T_J ≤ 225°C), case temperature (T_C ≤ 150°C), and thermal resistance (R_θJC = 0.31°C/W at 170 W). At 28 V and 1400 mA quiescent current, the device operates within thermal limits for 50 W avg. W-CDMA output. The MRF7S21170HSR3 datasheet emphasizes VSWR ruggedness and power compression metrics over DC current limits.

Does the MRF7S21170HSR3 require external input/output matching networks?

No, the MRF7S21170HSR3 is internally matched for 50 Ω systems across 2110–2170 MHz. Freescale's characterization data shows Z_source ≈ 4.4 – j9.4 Ω and Z_load ≈ 0.92 – j2.76 Ω at 2140 MHz, and the device is validated in test fixtures with minimal external components. While fine-tuning may improve ACPR or efficiency in specific layouts, the MRF7S21170HSR3 is designed for direct integration into 50 Ω transmission lines without mandatory external matching.

What is the meaning of the 'R3' suffix in MRF7S21170HSR3?

The 'R3' suffix in MRF7S21170HSR3 indicates tape-and-reel packaging: 250 units per reel, 56 mm tape width, and 13-inch reel diameter. This packaging format is optimized for automated SMT placement in high-volume RF power amplifier manufacturing. The 'H' in the part number denotes the NI-880 (Case 465B-04) package variant, distinguishing it from the HR3 variant in Case 465C-03.

Can the MRF7S21170HSR3 be used in Class C amplifier configurations?

Yes, the MRF7S21170HSR3 is explicitly characterized and optimized for Class C operation, featuring an extended negative gate-source voltage range to support deep cutoff biasing required in Doherty peaking stages. Its gate threshold voltage (V_GS(th) = 1.2–2.7 V) and quiescent gate voltage (V_GS(Q) = 2.7 V typ.) allow stable Class C biasing without risk of gate leakage or thermal runaway. The MRF7S21170HSR3 datasheet confirms suitability for Class C in CDMA and WLL applications.

What thermal interface material is recommended for mounting the MRF7S21170HSR3?

Freescale recommends using a thermally conductive, electrically insulating interface material such as Bergquist Sil-Pad 1000 or Parker Chomerics Thermasil III between the MRF7S21170HSR3 flanged baseplate and heatsink. The NI-880 package requires uniform pressure (25–35 psi) and surface flatness < 0.002 inch to achieve the specified 0.31°C/W junction-to-case thermal resistance. Thermal paste alone is insufficient; compliant pads ensure void-free contact and long-term reliability under thermal cycling.