NXP Semiconductors MRF373ALSR5

Overview

MRF373ALSR5 from Freescale Semiconductor is an N-channel enhancement-mode lateral RF power MOSFET designed for broadband common-source amplifier applications in 32 V transmitter systems operating from 470 to 860 MHz. It delivers 75 W CW output power at 860 MHz with 18.2 dB power gain and 60% drain efficiency, and is rated for 10:1 VSWR tolerance under full-power conditions.

For engineers reviewing the MRF373ALSR5 datasheet, MRF373ALSR5 pinout, MRF373ALSR5 application, or MRF373ALSR5 equivalent, this device requires attention to thermal management (RθJC = 0.63 °C/W), gate drive stability (VGS(th) = 2–4 V), and narrowband impedance matching (Zsource = 0.56 + j0.06 Ω @ 860 MHz) in UHF broadcast and cable TV headend amplifier designs.

Technical Context

This device operates as a high-power RF amplifier stage in fixed-bias Class AB configurations, optimized for 32 V DC supply and narrowband 50 Ω systems. Its lateral LDMOS structure provides robust VSWR tolerance and stable large-signal performance across the UHF band.

Thermal design is critical: junction temperature must remain ≤200°C, with case temperature limited to 150°C; the NI-360S package enables direct heatsink mounting via flange. ESD protection meets HBM Class 1 and MM Class M1 standards, supporting handling in production environments.

Key Specifications

Pinout & Package

The MRF373ALSR5 is housed in the NI-360S package (Case 360C-05, Style 1), a flanged ceramic/metal hermetic package with isolated lid and gold-plated leads (40 μ″ nominal). The flange serves as the thermal and electrical drain connection and must be mounted to a grounded, thermally conductive heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF373ALSR5, MRF373ALR1 offers identical RF performance but reduced thermal capability, while MRFE6VP61K25H delivers higher power and frequency range at the cost of gate drive complexity and non-interchangeable packaging-neither is pin-compatible, and both require layout and bias network changes.

Availability

MRF373ALSR5 is available at Aetrix Electronics and suitable for cable TV headend amplifiers, UHF broadcast transmitters, public safety radio repeaters, and industrial RF heating systems requiring stable component supply and long-term obsolescence management.

Supply support for MRF373ALSR5 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 since 2015) was a leading designer of RF power semiconductors, specializing in high-reliability, high-efficiency devices for wireless infrastructure and broadcast markets.

The MRF373ALSR5 belongs to Freescale's MRF373A family of lateral N-channel RF power MOSFETs, engineered specifically for rugged, high-efficiency UHF amplifier stages in commercial broadcast and CATV equipment.

FAQ

What is the maximum continuous drain current rating for the MRF373ALSR5?

The MRF373ALSR5 does not specify a maximum continuous drain current (ID) rating directly; instead, its safe operating area is defined by total device dissipation (PD = 278 W at TC = 25°C) and thermal resistance (RθJC = 0.63 °C/W). At 32 V drain supply and 75 W output, typical IDQ is 200 mA quiescent, with peak RF current reaching ~5.5 A during CW operation. Designers must verify current density against SOA curves in the official MRF373A datasheet Rev. 7.

Is the MRF373ALSR5 RoHS compliant and lead-free?

Yes, the MRF373ALSR5 is RoHS compliant per Directive 2011/65/EU, with no exemptions required for lead, cadmium, mercury, hexavalent chromium, PBB, or PBDE. Its leads feature 40 μ″ nominal gold plating, and the device is qualified for lead-free reflow soldering up to 260°C peak temperature, as confirmed in Freescale's MRF373A Rev. 7 documentation.

Does the MRF373ALSR5 support pulsed RF operation?

The MRF373ALSR5 is characterized and specified for continuous wave (CW) operation at 75 W, 32 V, and 860 MHz. While it can handle pulsed RF signals, Freescale does not publish pulse-width, duty-cycle, or peak power derating data for this device. For pulsed applications, designers must validate safe operating area using the published SOA graph and thermal time constants, and confirm gate drive stability under transient conditions.

What is the gate-source leakage current specification for the MRF373ALSR5?

The MRF373ALSR5 specifies a maximum gate-source leakage current (IGSS) of 1 μA at VGS = 5 Vdc and VDS = 0 Vdc, per Table 4 of the MRF373A Rev. 7 datasheet. This low leakage supports stable DC bias networks and minimizes gate drive current requirements in fixed-bias Class AB amplifier designs using the MRF373ALSR5.

Can the MRF373ALSR5 be used in push-pull or balanced amplifier configurations?

Yes, the MRF373ALSR5 is commonly deployed in push-pull and balanced amplifier topologies for improved linearity and even-order harmonic suppression. Its matched large-signal impedance characteristics (e.g., Zsource = 0.56 + j0.06 Ω @ 860 MHz) and symmetric thermal profile support balanced layouts. However, external hybrid couplers or transformers must be designed to match the device's 2 Ω reference impedance, as specified in Figure 5 of the MRF373A datasheet.