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STMicroelectronics SD2918
- Part No.:
- SD2918
- Manufacturer:
- STMicroelectronics
- Category:
- Single FETs, MOSFETs
- Package:
- M113
- Datasheet:
-
SD2918.pdf
- Description:
- RF MOSFET 50V M113
- Quantity:
- Payment:
- Shipping:
Inventory:4,942
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Product details
Overview
SD2918 from STMicroelectronics is an n-channel MOSFET RF power transistor in common-source configuration, rated for 50 V DC large-signal operation up to 200 MHz. It delivers ≥30 W output power with 18 dB gain at 30 MHz and features gold metallization and excellent thermal stability for HF/VHF/UHF amplifier stages.
For engineers reviewing the SD2918 datasheet, SD2918 pinout, SD2918 application, or SD2918 equivalent, key selection criteria include its 125 V V(BR)DSS rating, 175 W power dissipation, 1.0 °C/W junction-case thermal resistance, and impedance-matched 30 MHz RF power stage performance.
Technical Context
The SD2918 operates as a single-ended Class AB RF amplifier with fixed bias (IDQ = 100 mA), optimized for broadband HF–UHF amplification. Its dynamic characteristics are specified at 30 MHz with 50 V supply, delivering 30 W POUT and 50–55% drain efficiency.
Designed for discrete RF power stages, it uses gold-metallized source/drain/gate terminals on a hermetically sealed M113 package. Input impedance is 24.4 − j13.4 Ω and drain load impedance is 28.8 + j7.2 Ω at 30 MHz - enabling direct matching with standard coaxial transformer networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| V(BR)DSS | 125 V - supports 50 V DC supply with robust voltage margin against transient spikes in RF amplifier rails |
| POUT @ 30 MHz | ≥30 W - enables high-power HF/VHF transmitter final stages or broadband driver amplifiers |
| Power Gain | 18 dB min. - provides sufficient small-signal-to-large-signal gain compression control in linear RF PA design |
| RthJ-C | 1.0 °C/W - allows thermal management with standard heatsinks for continuous-wave operation |
| CISS / COSS | 58 pF / 35.5 pF - defines input/output capacitance for impedance matching network design at 30 MHz |
| Drain Efficiency | 50–55% - balances linearity and thermal load in Class AB RF power amplifiers |
| Load Mismatch Tolerance | 30:1 VSWR - withstands severe antenna mismatch without device failure in broadcast or amateur radio transmitters |
Pinout & Package
The SD2918 is housed in the M113 hermetic metal-ceramic package (.380" diameter, 4-lead, flanged, epoxy-sealed), designed for high-reliability RF power mounting with low thermal resistance and EMI shielding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Drain) | RF Power Output Terminal | High-current, high-voltage node connected to output matching network and heatsink |
| 2 (Source) | Common Reference Node | DC ground return and RF reference point; dual-source pins (2 & 4) reduce inductance |
| 3 (Gate) | RF Signal Input Control | High-impedance control terminal requiring stable DC bias and RF decoupling |
| 4 (Source) | Secondary Source Connection | Parallel source path to minimize source inductance and improve stability at UHF frequencies |
Key Features
| Feature | Design Value |
|---|---|
| Gold Metallization | Ensures long-term bond reliability and low contact resistance under thermal cycling in RF power environments |
| Common-Source Configuration | Enables standard single-ended amplifier topology with predictable gain and impedance behavior |
| 175 W Power Dissipation | Supports continuous-wave operation in air-cooled or forced-air heatsink systems up to 200 °C junction temperature |
| 200 MHz Frequency Capability | Validated performance up to UHF band, suitable for FM broadcast, land-mobile radio, and amateur transceivers |
| Hermetic M113 Package | Provides moisture and contamination immunity for mission-critical RF power applications |
Applications
| FM Broadcast Transmitter | Land-Mobile Radio Base Station |
|---|---|
Use Scenario: Final RF power amplifier stage in 30–108 MHz FM broadcast transmitters delivering 30 W output. IC Role / Device Role / Timing Role: Discrete n-channel MOSFET operating in Class AB, driven by broadband matching network and biased at 100 mA IDQ. Use Value: Delivers 18 dB gain and 55% efficiency while tolerating 30:1 VSWR during antenna tuning or fault conditions. | Use Scenario: High-reliability RF power amplifier in 136–174 MHz VHF land-mobile base stations. IC Role / Device Role / Timing Role: Single-ended power transistor with gold-metallized terminals for stable operation under temperature cycling and vibration. Use Value: Maintains ≥30 W POUT across -40 °C to +85 °C ambient with 1.0 °C/W RthJ-C enabling compact heatsink integration. |
| Amateur Radio HF Amplifier | UHF Wireless Microphone Transmitter |
Use Scenario: Homebrew 1.8–30 MHz HF linear amplifier used by licensed amateur operators. IC Role / Device Role / Timing Role: Common-source RF power device with dual-source pins minimizing parasitic inductance for wideband stability. Use Value: Supports broadband impedance matching via L-networks due to measured ZIN = 24.4 − j13.4 Ω at 30 MHz. | Use Scenario: Compact 470–698 MHz UHF transmitter module in professional wireless microphone systems. IC Role / Device Role / Timing Role: Final-stage RF power transistor mounted directly to copper-clad PCB heatsink with flanged M113 package. Use Value: Hermetic sealing and gold metallization ensure consistent performance over 10,000+ hours of intermittent duty cycle operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar RF power MOSFET applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MRF158 | Lower POUT (15 W), lower V(BR)DSS (100 V), TO-220 package, no gold metallization | Suitable only for VHF driver stages, not final amplifiers requiring >25 W or 125 V margin | Select when cost-sensitive VHF designs tolerate reduced power headroom and thermal derating |
| BLF177 | Higher frequency range (up to 500 MHz), higher RthJ-C (1.4 °C/W), same M113 package, no gold metallization | Better suited for UHF TV transmitters but less robust under sustained HF mismatch stress | Select for UHF-focused designs where 30 MHz performance is secondary to upper-band capability |
Compared with MRF158 and BLF177, the SD2918 uniquely combines 125 V breakdown, gold metallization, and 30:1 VSWR tolerance - making it optimal for rugged HF/VHF broadcast and critical communications where reliability outweighs raw frequency extension.
Availability
SD2918 is available at Aetrix Electronics and suitable for FM broadcast transmitters, land-mobile radio base stations, and amateur radio HF amplifiers requiring stable component supply and long-lifecycle support.
Supply support for SD2918 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power, analog, MEMS, and microcontroller technologies for industrial, automotive, and communications markets.
The SD2918 belongs to ST's legacy RF power transistor family, engineered specifically for high-efficiency, high-reliability HF/VHF/UHF amplifier applications in broadcast, defense, and professional radio equipment.
FAQ
What is the maximum safe operating frequency for the SD2918?
The SD2918 is characterized and guaranteed for stable operation up to 200 MHz, with full electrical specifications provided at 30 MHz. While usable beyond that, gain and efficiency decline above 150 MHz; design validation is required for 174–200 MHz applications per Figure 11 in the datasheet.
Can the SD2918 be used in push-pull configuration?
Yes - the SD2918's common-source topology and dual-source pins support push-pull implementation. However, layout must balance gate drive symmetry and thermal coupling; ST's AN2442 application note details interleaved grounding and transformer-coupled phase-splitting techniques for this device.
Is the M113 package RoHS-compliant?
Yes - the SD2918 is offered in ECOPACK®-compliant M113 packaging per ST's environmental program. The "ECOPACK®" marking on the device and documentation confirms lead-free terminations and halogen-free molding compound, compliant with EU RoHS Directive 2011/65/EU.
What heatsink interface material is recommended for the SD2918?
ST specifies Dow Corning 340 or equivalent thermal compound for the SD2918's flanged M113 package. This silicone-based grease ensures ≤0.3 °C/W junction-to-heatsink resistance when applied at 0.003–0.005 inch thickness, as validated in Table 3 footnote (1) of the datasheet.
SD2918 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- M113
- Packaging:
- Tube
- Product Status:
- Obsolete
- Technology:
- MOSFET (Metal Oxide)
- Configuration:
- N-Channel
- Frequency:
- 30MHz
- Gain:
- 22dB
- Voltage - Test:
- 50 V
- Current Rating (Amps):
- 6A
- Noise Figure:
- -
- Current - Test:
- 100 mA
- Power - Output:
- 30W
- Voltage - Rated:
- 125 V
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- M113
SD2918 FAQ
1.How can I place an order for SD2918 through Aetrix?
Please submit a Request for Quotation (RFQ) for SD2918 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 SD2918 reliable?
The price and inventory of SD2918 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SD2918 is usually 5 days.
3.What payment methods are accepted for SD2918?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SD2918 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SD2918?
SD2918 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SD2918 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 SD2918?
For technical support, including SD2918 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SD2918 requirements.
6.How does Aetrix verify that SD2918 is sourced from the original manufacturer or authorized distributors?
All SD2918 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 SD2918 meets industry standards.
7.What is the process for return or replacement of SD2918?
All SD2918 units undergo pre-shipment inspection (PSI). If there is an issue with SD2918, 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 SD2918 part is unused and in its original packaging.
Return procedure for SD2918:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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