MRF8S21120HSR3 - 28W RF Power MOSFET 2110-2170 MHz | NXP
MPN: MRF8S21120HSR3 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $93.39 | $93.39 |
| 10 | $82.5 | $825.00 |
| 100 | $72 | $7,200.00 |
| 250 | $65.5 | $16,375.00 |
| 500 | $59.95 | $29,975.00 |
MRF8S21120HSR3 Overview
A RF power MOSFET is a discrete transistor specifically engineered to amplify high-frequency signals in the MHz-to-GHz range. Unlike generic switching MOSFETs used in DC-DC converters, RF power MOSFETs use a lateral structure with carefully engineered interdigitation of gate, drain, and source fingers to minimize parasitic capacitance and maximize gain at RF frequencies. Within the taxonomy, MRF8S21120HSR3 belongs to the family of RF power transistors -> discrete semiconductors -> power amplifiers -> wireless infrastructure components, and sits in NXP's Airfast RF power family, which dominates cellular base station transmitter designs through the 4G era and into early 5G upgrade modules.
Key features include a typical CW output power capability well above the 28 W average rating for pulsed W-CDMA signals, integrated ESD protection, a thermal resistance (theta_JC) optimized for liquid-cooled or forced-air heatsinking in macro base stations, and a ruggedness level capable of surviving 10:1 VSWR at the rated output. The device is specified for operation between 2110 MHz and 2170 MHz - exactly the downlink band of the global 3GPP Band 1 (IMT-2000/UMTS), making it a drop-in final-stage device for most macro-cell transmit lineups serving that band.
The MRF8S21120HSR3 uses a high-voltage LDMOS (Laterally Diffused MOSFET) process on a ceramic flange (NI-780HS) package with source on the case for direct chassis-ground mounting. The device is intended to be bolted to a heatsink or cold plate; thermal management is critical because at full output the die must dissipate up to 4-5 times the average RF power as heat. The part is also available as MRF8S21120HR3 (push-pull balanced version in a slightly different outline) for Doherty amplifier configurations.
Typical applications include W-CDMA/LTE macro base station power amplifiers, Band 1 (2100 MHz) final-stage amplifiers, general-purpose Class AB RF power amplifiers from 2110-2170 MHz, driver stages in higher-power Doherty layouts, and upgrade/transmitter lineups for distributed antenna systems and small-cell base stations. Designers typically pair it with NXP's MRF8S21120HSR3 as the main device and a smaller peak amplifier such as the MRF6S21100N for Doherty operation.
When designing with this part, allocate copper-clad footprints and load-pull-correct matching networks, and ensure the gate bias network provides a low-impedance path to ground at the operating frequency. Use gate-source clamping protection as recommended in the NXP datasheet to prevent thermal runaway during fault conditions. Designers should also account for the source being case-connected - any heatsink must be electrically isolated from RF ground using an insulator pad and thermal grease.
Drop-in alternatives for MRF8S21120HSR3 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MRF8S21120HSR3 (same form factor and footprint) — differing in RoHS Status, Application, Frequency Range, Manufacturer, Mounting Style.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MRF8S21120HR3
✅ Drop-In📋 Reference alternative (not in catalog)
MRF8S21120HS
✅ Drop-In📋 Reference alternative (not in catalog)
MRF8S18120HSR3
✅ Drop-In✓ In Stock
$65 / Unit
View Datasheet →MRF8S21240HR3
✅ Drop-In📋 Reference alternative (not in catalog)
MRF8S21120HSR3 Maximum Ratings & Electrical Characteristics
| Manufacturer | NXP Semiconductors (formerly Freescale) |
| Part Number | MRF8S21120HSR3 |
| Device Type | N-Channel Enhancement-Mode Lateral RF Power MOSFET |
| Frequency Range | 2110-2170 MHz |
| Output Power (P1dB / average) | 28 W average, W-CDMA / LTE |
| Drain-Source Breakdown Voltage V(BR)DSS | 65 V |
| Operating Drain Voltage | 28 V |
| Power Gain (Typical) | 17.6 dB at 2.17 GHz |
| Operating Mode | Class AB / Class C |
| Package Type | NI-780HS (ceramic flange) |
| Case Mounting | Source on case (flange grounding) |
| Number of Pins | 2-pin (Gate, Drain) |
| Mounting Style | Through-hole / bolt-down flange |
| MSL Level | 1 (unlimited) |
| RoHS Status | RoHS compliant |
| Lead-Free | Yes |
MRF8S21120HSR3 Pin Configuration
| Pin 1 | GATE — RF input gate; bias ~3 V for Class AB quiescent |
| Pin 2 | DRAIN — RF output drain; supply 28 V via RF choke |
| Pin FLANGE | SOURCE / GROUND — Source connected to case flange; thermal and RF ground |
MRF8S21120HSR3 Safe Operating Area (RF pulsed, 10 us / 10% duty)
Typical Applications
MRF8S21120HSR3 is suitable for 6 applications: W-CDMA Band-1 Macro Base Station Final Stage, LTE Base Station Power Amplifier (4G), Class AB RF Power Amplifier (2110-2170 MHz), Driver Stage for Higher-Power Doherty, Public-Safety / Band-1 Repeater PA, Distributed Antenna System (DAS) Hub.
W-CDMA Band-1 Macro Base Station Final Stage
The MRF8S21120HSR3 is designed as the final-stage amplifier in 3GPP Band-1 (2110-2170 MHz) macro-cell W-CDMA base stations delivering 28 W average output to the antenna. Its 17.6 dB typical gain and 100% PAR-tested linearity support the high peak-to-average ratio of W-CDMA signals with sufficient margin for adjacent-channel leakage ratio (ACLR). The 65 V V(BR)DSS and 28 V nominal operating rail give a 2x breakdown-to-operating margin that protects the device under antenna VSWR mismatch events. Designers bias the gate at ~3 V to set quiescent current around 130 mA for Class AB operation; efficiency typically lands around 30-35% for the target 28 W output.
Recommended
LTE Base Station Power Amplifier (4G)
This part is purpose-built for LTE base station transmitters operating in Band 1, Band 4, or Band 10 (all in 2110-2170 MHz). It is 100% PAR tested to handle the high crest factor of OFDM LTE downlink signals without clipping. Placed as the final stage after a Doherty splitter, it delivers 28 W average continuous and survives the brutal thermal stress of always-on cellular retransmission. Compared to a smaller 10 W amplifier, the MRF8S21120HSR3 lets macro cells cover longer distances per radio chain, reducing tower equipment count. Heat from the die is dumped through the source-flange into a forced-air or liquid cold plate.
Recommended
Class AB RF Power Amplifier (2110-2170 MHz)
Beyond Doherty, the MRF8S21120HSR3 is well suited to classic Class AB broadband amplification in the 2110-2170 MHz range. Designers tune it with a 50-ohm input/output matching network based on the S-parameters in the NXP datasheet to deliver 28 W CW without elaborate filtering. Class AB operation strikes a balance between linearity (good for carrier aggregation) and efficiency (typically 30-40%); the 28 V supply and 17.6 dB gain simplify the upstream driver chain. This topology is common in test-and-measurement transmitters and in small-cell eNodeB transmit modules.
Recommended
Driver Stage for Higher-Power Doherty
When stacked two-up to reach 56 W or used ahead of a higher-power (240 W+) Airfast final like the MRF8S21240HR3, the MRF8S21120HSR3 serves as a 28 W main amplifier whose output feeds a quadrature combiner with a parallel peak amplifier. Its gain of 17.6 dB leaves only 1-2 dB for the final stage to contribute, simplifying loop stability analysis. The NI-780HS flange shares the mounting pattern of bigger Airfast devices, making the PCB-to-heatsink interface reusable across power tiers.
Recommended
Public-Safety / Band-1 Repeater PA
Narrow-band public-safety and cellular repeaters operating at 2110-2170 MHz band 1 (3GPP/UMTS downlink) employ the MRF8S21120HSR3 as their final PA because it can deliver 28 W average at high linearity without exotic GaN cost premiums. The LDMOS technology provides additional bandwidth margin for the system's digital pre-distortion (DPD) feedback path. Bolt-down NI-780HS mounting allows direct integration into the repeater chassis; matched-network design files are available from NXP's reference-design library.
Recommended
Distributed Antenna System (DAS) Hub
In DAS deployments feeding 50-100 indoor antennas from a single carrier hub, the MRF8S21120HSR3 provides the RF amplification just before the DAS coax/fiber backhaul split. Its 28 W average capability and rugged 65 V breakdown handle the high reflected-power environment of complex comb networks. Mounted to a shared chassis heatsink, multiple MRF8S21120HSR3s in parallel can be combined to 80-100 W aggregate output for large-venue deployments. 28 V supply aligns with telecom-grade power over Ethernet plus DC-DC conversion, simplifying the power architecture.
Recommended
Recommended Products Summary
Engineering reference data for MRF8S21120HSR3 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MRF8S21120HR3 | MRF8S21120HS | MRF8S18120HSR3 | MRF8S21240HR3 |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | NI-780HS ceramic flange | NI-780 push-pull | NI-780HS (same) | NI-780HS (same) | NI-780 family |
| Frequency Range | 2110-2170 MHz | 2110-2170 MHz | 2110-2170 MHz | 1805-1880 MHz | 2110-2170 MHz |
| Average Output Power | 28 W | 28 W | 28 W | 28 W (different band) | 240 W (higher) |
| Drain-Source Breakdown V(BR)DSS | 65 V | 65 V | 65 V | 65 V | 65 V |
| Operating Voltage | 28 V | 28 V | 28 V | 28 V | 28 V |
| Topology | Single-ended | Push-pull balanced | Single-ended | Single-ended | Single-ended |
Key Differentiators
- Highest-volume 28 W / 28 V / 2.1 GHz LDMOS on the market (vs MRF6S21100NR1)
- Band-1 (2.1 GHz) optimized matching network (vs MRF8S18120HSR3)
- Single-ended NI-780HS flange simplifies heatsink integration (vs MRF8S21120HR3)
Design Notes
At 28 W RF output and ~32% efficiency, the die dissipates approximately 60 W of heat. Estimated input: Pout = 28 W, eta = 32%, VDD = 28 V -> Pdiss = Pout/eta - Pout ~ 60 W. The NI-780HS flange MUST be mounted to a cold plate or forced-air heatsink rated for 60 W continuous; insulate the flange electrically from the chassis using a beryllium-oxide-free thermal pad (the source is on the flange and serves as RF ground). Use a thin layer of high-quality thermal compound to keep R_therm below 0.3 C/W. Monitor the heatsink temp in qualification - junction must stay below 200 C.
The gate-bias network should include a voltage divider with low-impedance decoupling (10 uF electrolytic + 100 nF + 10 nF ceramic stack) at the gate pin to prevent RF leakage into the DC bias supply. The drain-side bias-T uses a quarter-wave microstrip with an RF choke (typically a 10-100 nH air-core or toroid inductor rated >2x DC current). All RF traces on the PCB should be 50-ohm controlled-impedance lines (microstrip or stripline), and the input/output matching networks should follow the load-pull data in the NXP datasheet for the target output power and linearity. Keep gate and drain traces physically separated by at least 3x the substrate height to isolate input from output and prevent oscillation.
Estimated: with the source tied to the flange, any heatsink or chassis will be at DC ground potential - do NOT assume the heatsink is floating; it must be tied to chassis ground via an external strap. Do not bias the gate above 4.5 V or below 0 V (the device is enhancement-mode and can be damaged by negative gate transients). For ESD safety, follow the gate-protection network from the NXP reference design (typically a 10 kohm gate resistor with back-to-back clamp diodes). For W-CDMA/LTE signals with PAR > 10 dB, ensure the drain supply can source at least 4x the average current for transient peaks (recommended 30+ A capability on the 28 V rail). Source: NXP MRF8S21120H datasheet application information.
Compliance Information
RoHS compliance confirmed per Mouser/DigiKey listing. Not AEC-Q100 qualified - this is a telecom infrastructure RF part. REACH and halogen-free status not explicitly listed in available web data.
