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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > Single FETs, MOSFETs

NXP Semiconductors MRF18085ALSR3

Name: MRF18085ALSR3
Brand: NXP Semiconductors
SKU: MRF18085ALSR3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MRF18085ALSR3

Manufacturer:: NXP Semiconductors

Category:: Single FETs, MOSFETs

Package:: NI-780S

Datasheet:: MRF18085ALSR3.pdf

Description:: RF MOSFET LDMOS 26V NI780

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MRF18085ALSR3 from Freescale Semiconductor is an N-channel enhancement-mode lateral RF power MOSFET designed for GSM/GSM EDGE base station amplifiers operating at 1805–1880 MHz. It delivers 85 W CW output power with 15 dB typical power gain and 52% typical drain efficiency at 26 Vdc, supporting Class AB operation in PCN/PCS cellular and WLL infrastructure applications.

For engineers reviewing the MRF18085ALSR3 datasheet, MRF18085ALSR3 pinout, MRF18085ALSR3 application, or MRF18085ALSR3 equivalent, key selection criteria include its 1805–1880 MHz full-band GSM-EDGE performance, 5:1 VSWR ruggedness at 85 W, internally matched 50 Ω input/output, and NI-780S package with gold-plated leads (40 μ″ nominal).

Technical Context

This device operates as a common-source RF power amplifier stage with gate threshold voltage of 2–4 Vdc and quiescent gate voltage of 2.5–4.5 Vdc at 800 mA IDQ. Its dynamic characteristics include 3.6 pF typical reverse transfer capacitance and –12 dB typical input return loss at 85 W, enabling stable broadband matching across the 1805–1880 MHz band.

The MRF18085ALSR3 is characterized using series-equivalent large-signal impedance parameters (e.g., Z_source = 1.13 – j3.62 Ω at 1710 MHz), optimized for maximum gain flatness and thermal stability up to 150°C case temperature, with junction-to-case thermal resistance of 0.79°C/W.

Key Specifications

Parameter	Value and Actual Design Meaning
Frequency Range	1805–1880 MHz full-band GSM/GSM EDGE operation; supports multicarrier TDMA/CDMA amplifiers without retuning.
Output Power	85 W CW at 26 Vdc, 800 mA IDQ; P1dB = 90 W ensures headroom for peak envelope power handling.
Power Gain	15 dB typical at 85 W; enables single-stage amplification in macrocell BTS final stages with minimal driver complexity.
Drain Efficiency	52% typical at 85 W; reduces thermal load and DC power consumption in high-power base station PA modules.
VSWR Tolerance	Withstands 5:1 VSWR at 1840 MHz, 85 W CW, 26 Vdc; eliminates need for external circulators in antenna mismatch scenarios.
Thermal Resistance	R_θJC = 0.79°C/W; allows direct mounting to heatsink with predictable junction temperature rise under full load.
ESD Protection	HBM Class 1 / MM Class M3 rated; provides robust handling during PCB assembly and field service without added protection circuitry.

Pinout & Package

Package: NI-780S (Case 465A-06, Style 1), ceramic/metal hermetic package with flange-mount thermal interface and 3-terminal leadframe. Gold plating thickness: 40 μ″ nominal on leads. RoHS compliant, supplied in tape-and-reel (250 units per 56 mm, 13-inch reel).

Pin/Terminal	Circuit Role	Design Meaning
1. DRAIN	High-current RF output node	Connected to output matching network and heatsink; carries full RF output current and DC supply voltage (26 Vdc).
2. GATE	RF input control terminal	Bias-controlled terminal requiring stable DC gate voltage (2.5–4.5 Vdc) and low-impedance RF drive; internally ESD-protected.
5. SOURCE	Common reference and RF return path	DC ground reference for bias network; RF return path for gate and drain circuits; bonded directly to flange for low-inductance grounding.

Key Features

Feature	Design Value
Internally matched I/O	Eliminates external input/output matching components across 1805–1880 MHz, reducing BOM count and layout sensitivity.
High linearity at 85 W	Enables clean spectral emission in GSM EDGE modulation (8-PSK), meeting ACLR requirements without digital predistortion overhead.
Integrated ESD protection	Meets HBM Class 1 and MM Class M3 standards, allowing safe handling and assembly without additional TVS or RC clamps.
Optimized phase flatness	Minimizes group delay variation across band, critical for multi-carrier amplification where intermodulation distortion must be tightly controlled.
Thermal stability up to 150°C TC	Enables reliable operation in sealed outdoor BTS enclosures with passive cooling, avoiding thermal runaway under ambient extremes.

Applications

GSM Base Station Final PA	WLL Microwave Transmitter
Use Scenario: Final-stage power amplifier in 1800 MHz GSM macrocell base stations delivering 40–85 W per carrier. IC Role / Device Role / Timing Role: High-efficiency RF power transistor operating in Class AB, driven by pre-driver stage and feeding diplexer/coupler network. Use Value: Delivers 52% efficiency at 85 W, reducing system-level heat dissipation and AC power draw while maintaining >13.5 dB gain across full band.	Use Scenario: Transmit amplifier in fixed wireless access (WLL) point-to-multipoint systems operating in 1800–1880 MHz licensed spectrum. IC Role / Device Role / Timing Role: Linear RF power stage supporting QPSK/16-QAM modulation with low adjacent channel leakage. Use Value: Achieves –12 dB input return loss and 5:1 VSWR tolerance, ensuring stable operation into variable antenna loads over temperature and aging.
TDMA/CDMA Multicarrier PA	Cellular Infrastructure Repeater
Use Scenario: Broadband amplifier in hybrid TDMA/CDMA base stations requiring simultaneous amplification of multiple carriers in 1805–1880 MHz band. IC Role / Device Role / Timing Role: Common-source power device biased for linear Class AB operation with externally tuned harmonic termination. Use Value: Provides 15 dB gain flatness ±0.5 dB and series-equivalent impedance data (Z_load, Z_source) for precise broadband matching network design.	Use Scenario: Bidirectional repeater unit deployed in rural cellular coverage extension, amplifying uplink/downlink signals between donor and coverage antennas. IC Role / Device Role / Timing Role: High-ruggedness RF transistor used in downlink transmit chain, handling reflected power from mismatched donor antenna. Use Value: Withstands 5:1 VSWR at full 85 W CW without degradation, eliminating need for isolators and reducing insertion loss in repeater RF path.

GSM Base Station Final PA

WLL Microwave Transmitter

Use Scenario: Final-stage power amplifier in 1800 MHz GSM macrocell base stations delivering 40–85 W per carrier.

IC Role / Device Role / Timing Role: High-efficiency RF power transistor operating in Class AB, driven by pre-driver stage and feeding diplexer/coupler network.

Use Value: Delivers 52% efficiency at 85 W, reducing system-level heat dissipation and AC power draw while maintaining >13.5 dB gain across full band.

Use Scenario: Transmit amplifier in fixed wireless access (WLL) point-to-multipoint systems operating in 1800–1880 MHz licensed spectrum.

IC Role / Device Role / Timing Role: Linear RF power stage supporting QPSK/16-QAM modulation with low adjacent channel leakage.

Use Value: Achieves –12 dB input return loss and 5:1 VSWR tolerance, ensuring stable operation into variable antenna loads over temperature and aging.

TDMA/CDMA Multicarrier PA

Cellular Infrastructure Repeater

Use Scenario: Broadband amplifier in hybrid TDMA/CDMA base stations requiring simultaneous amplification of multiple carriers in 1805–1880 MHz band.

IC Role / Device Role / Timing Role: Common-source power device biased for linear Class AB operation with externally tuned harmonic termination.

Use Value: Provides 15 dB gain flatness ±0.5 dB and series-equivalent impedance data (Z_load, Z_source) for precise broadband matching network design.

Use Scenario: Bidirectional repeater unit deployed in rural cellular coverage extension, amplifying uplink/downlink signals between donor and coverage antennas.

IC Role / Device Role / Timing Role: High-ruggedness RF transistor used in downlink transmit chain, handling reflected power from mismatched donor antenna.

Use Value: Withstands 5:1 VSWR at full 85 W CW without degradation, eliminating need for isolators and reducing insertion loss in repeater RF path.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MRF18085ALR3	Different package: NI-780 (Case 465-06) vs. NI-780S; identical electrical specs and thermal rating but distinct mechanical footprint and lead count (3-pin vs. 5-pin).	Requires PCB redesign due to different flange dimensions, pin spacing, and thermal pad layout; not interchangeable without layout change.	Select MRF18085ALR3 only when legacy NI-780 footprint is mandated; verify heatsink interface compatibility.
PD57018-E	STMicroelectronics 1800 MHz LDMOS; 85 W Pout, 14.5 dB gain, 50% efficiency; higher Crss (5.2 pF) and lower VSWR tolerance (3.5:1).	Designed for similar GSM EDGE base stations but requires external input matching and has reduced ruggedness margin.	Choose PD57018-E if sourcing flexibility is prioritized and VSWR stress is mitigated via circulator; validate thermal interface with R_θJC = 0.9°C/W.

Compared with MRF18085ALR3, the MRF18085ALSR3 offers identical RF performance but improved manufacturability via NI-780S packaging and finer gold plating control; versus PD57018-E, it provides superior VSWR ruggedness and internal matching-critical for cost-sensitive, high-reliability macrocell deployments.

Availability

MRF18085ALSR3 is available at Aetrix Electronics and suitable for GSM base station transmitters, WLL microwave transmitters, and TDMA/CDMA multicarrier amplifiers requiring stable component supply, long-lifecycle support, and traceable industrial-grade RF power devices.

Supply support for MRF18085ALSR3 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, thermally robust, and application-validated solutions for cellular base stations.

The MRF18085ALSR3 belongs to Freescale's MRF180xxA family of lateral N-channel MOSFETs, engineered specifically for 1800 MHz GSM/GSM EDGE macrocell and microcell base station power amplifiers demanding high gain, linearity, and ruggedness.

FAQ

What is the maximum operating junction temperature for the MRF18085ALSR3?

The MRF18085ALSR3 has a maximum operating junction temperature (T_J) of 200°C, verified per Freescale's thermal characterization methodology (AN1955/D). This rating enables reliable operation under sustained 85 W CW output with proper heatsinking, as confirmed by its 0.79°C/W junction-to-case thermal resistance. The MRF18085ALSR3 must be mounted to a thermally adequate heatsink to maintain T_J ≤ 200°C under worst-case ambient and power conditions.

Does the MRF18085ALSR3 require external input/output matching networks?

No-the MRF18085ALSR3 is internally matched for 50 Ω operation across the full 1805–1880 MHz GSM EDGE band, as stated in Freescale's technical data and validated in their test fixture design. This eliminates discrete matching components at both input and output, simplifying PCB layout and improving production consistency. The MRF18085ALSR3 achieves –12 dB input return loss and stable gain without external tuning, though external harmonic filtering may still be required per system specifications.

What is the gate threshold voltage range for the MRF18085ALSR3?

The MRF18085ALSR3 has a gate threshold voltage (V_GS(th)) range of 2.0–4.0 Vdc, measured at V_DS = 10 Vdc and I_D = 200 μAdc. This parameter defines the minimum gate voltage needed to initiate conduction and is critical for setting stable Class AB bias. The MRF18085ALSR3's specified V_GS(Q) of 2.5–4.5 Vdc at I_DQ = 800 mA confirms its suitability for precision gate-bias networks in high-linearity RF power amplifier designs.

How does the MRF18085ALSR3 handle load mismatches in base station applications?

The MRF18085ALSR3 is rated to withstand 5:1 VSWR at 1840 MHz, 85 W CW, and 26 Vdc-verified per Freescale's ruggedness testing protocol. This capability allows it to operate safely under antenna detuning, cable faults, or environmental impedance shifts without failure or parametric drift. Unlike many competing RF transistors, the MRF18085ALSR3 does not require external circulators or isolators in standard macrocell deployments, directly lowering system cost and insertion loss. The MRF18085ALSR3's robustness is enabled by its lateral MOSFET structure and integrated thermal protection design.

Is the MRF18085ALSR3 RoHS compliant and what does the 'R3' suffix indicate?

Yes, the MRF18085ALSR3 is RoHS compliant, as explicitly stated in Freescale's archived technical data. The 'R3' suffix denotes tape-and-reel packaging: 250 units per 56 mm wide, 13-inch diameter reel. This format supports automated SMT placement in high-volume RF power amplifier module manufacturing. The 'LS' in MRF18085ALSR3 further specifies low-gold-plating thickness (40 μ″ nominal) on the leads, balancing solderability, wire-bond compatibility, and cost for hermetic ceramic packages. The MRF18085ALSR3 meets all applicable EU RoHS Directive restrictions on hazardous substances.

MRF18085ALSR3 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

Package/Case:: NI-780S

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Technology:: LDMOS

Configuration:: -

Frequency:: 1.81GHz ~ 1.88GHz

Gain:: 15dB

Voltage - Test:: 26 V

Current Rating (Amps):: -

Noise Figure:: -

Current - Test:: 800 mA

Power - Output:: 85W

Voltage - Rated:: 65 V

Grade:: -

Qualification:: -

Mounting Type:: Chassis Mount

Supplier Device Package:: NI-780S

MRF18085ALSR3 FAQ

1.How can I place an order for MRF18085ALSR3 through Aetrix?

Please submit a Request for Quotation (RFQ) for MRF18085ALSR3 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MRF18085ALSR3 reliable?

The price and inventory of MRF18085ALSR3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MRF18085ALSR3 is usually 5 days.

3.What payment methods are accepted for MRF18085ALSR3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MRF18085ALSR3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MRF18085ALSR3?

MRF18085ALSR3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MRF18085ALSR3 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MRF18085ALSR3?

For technical support, including MRF18085ALSR3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MRF18085ALSR3 requirements.

6.How does Aetrix verify that MRF18085ALSR3 is sourced from the original manufacturer or authorized distributors?

All MRF18085ALSR3 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MRF18085ALSR3 meets industry standards.

7.What is the process for return or replacement of MRF18085ALSR3?

All MRF18085ALSR3 units undergo pre-shipment inspection (PSI). If there is an issue with MRF18085ALSR3, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MRF18085ALSR3 part is unused and in its original packaging.

Return procedure for MRF18085ALSR3:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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