Communication Concepts MRF154 User Manual

Page 1
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
Designed primarily for linear large signal output stages in the 2.0 to 100 MHz frequency range.
N–Channel enhancement mode MOSFET
Specified 50 volts, 30 MHz characteristics
Output power = 600 watts Power gain = 17 dB (typ.) Efficiency = 45% (typ.)
M/A-COM Products
Released - Rev. 07.07
Product Image
1
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Page 2
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
M/A-COM Products
Released - Rev. 07.07
2
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Page 3
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
M/A-COM Products
Released - Rev. 07.07
3
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Page 4
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
M/A-COM Products
Released - Rev. 07.07
4
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Page 5
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
M/A-COM Products
Released - Rev. 07.07
5
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Page 6
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
M/A-COM Products
Released - Rev. 07.07
6
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Page 7
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
RF POWER MOSFET CONSIDERATIONS
The physical structure of a MOSFET results in capacitors between the terminals. The metal oxide gate structure de­termines the capacitors from gate–to–drain (Cgd), and gate–to–source (Cgs). The PN junction formed during the fabrication of the RF MOSFET results in a junction capaci­tance from drain–to–source (Cds).
These capacitances are characterized as input (Ciss), output (Coss) and reverse transfer (Crss) capacitances on data sheets. The relationships between the inter–terminal capacitances and those given on data sheets are shown below. The
Ciss can be specified in two ways:
1.Drain shorted to source and positive voltage at the gate.
2.Positive voltage of the drain in respect to source and
zero volts at the gate. In the latter case the numbers are lower. However, neither method represents the actual oper­ating conditions in RF applications.
LINEARITY AND GAIN CHARACTERISTICS
In addition to the typical IMD and power gain data pre­sented, Figure 5 may give the designer additional informa­tion on the capabilities of this device. The graph represents the small signal unity current gain frequency at a given drain current level. This is equivalent to fT for bipolar tran­sistors. Since this test is performed at a fast sweep speed, heating of the device does not occur. Thus, in normal use, the higher temperatures may degrade these characteristics to some extent.
DRAIN CHARACTERISTICS
One figure of merit for a FET is its static resistance in the full–on condition. This on–resistance, VDS(on), occurs in the linear region of the output characteristic and is specified under specific test conditions for gate–source voltage and drain current. For MOSFETs, VDS(on) has a positive tem­perature coefficient and constitutes an important design consideration at high temperatures, because it contributes to the power dissipation within the device.
M/A-COM Products
Released - Rev. 07.07
GATE CHARACTERISTICS
The gate of the RF MOSFET is a polysilicon material, and is electrically isolated from the source by a layer of oxide. The input resistance is very high — on the order of 109 ohms — resulting in a leakage current of a few nanoamperes. Gate control is achieved by applying a positive voltage slightly in excess of the gate–to–source threshold voltage, VGS(th).
Gate Voltage Rating — Never exceed the gate voltage rating. Exceeding the rated VGS can result in permanent damage to the oxide layer in the gate region.
Gate Termination — The gates of these devices are es­sentially capacitors. Circuits that leave the gate open– circuited or floating should be avoided. These conditions can result in turn–on of the devices due to voltage build–u p on the input capacitor due to leakage currents or pickup.
Gate Protection — These devices do not have an internal monolithic zener diode from gate–to–source. If gate protec­tion is required, an external zener diode is recommended.
MOUNTING OF HIGH POWER RF POWER TRANSISTORS
The package of this device is designed for conduction
cooling. It is extremely important to minimize the thermal resistance between the device flange and the heat dissipa­tor.
Since the device mounting flange is made of soft copper, itmay be deformed during various stages of handling or during transportation. It is recommended that the user makes a final inspection on this before the device installa­tion. ±0.0005, is considered sufficient for the flange bottom.
The same applies to the heat dissipator in the device mounting area. If copper heatsink is not used, a copper head spreader is strongly recommended between the de­vice mounting surfaces and the main heatsink. It should be at least 1/4, thick and extend at least one inch from the flange edges. A thin layer of thermal compound in all inter­faces is, of course, essential. The recommended torque on the 4–40 mounting screws should be in the area of 4–5 lbs.–inch, and spring type lock washers along with flat washers are recommended.
For die temperature calculations, the Δ temperature from a corner mounting screw area to the bottom center of the flange is approximately 5°C and 10°C under normal operat­ing conditions (dissipation 150 W and 300 W respectively).
The main heat dissipater must be sufficiently large and have low Rθ for moderate air velocity, unless liquid cooling is employed.
7
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
Page 8
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
CIRCUIT CONSIDERATIONS
At high power levels (500 W and up), the circuit layout becomes critical due to the low impedance levels an d high RF currents associated with the output matching. Some of the components, such as capacitors and inductors must also withstand these currents. The component losses are directly proportional to the operating frequency. The manu­facturers
M/A-COM Products
Released - Rev. 07.07
specifications on capacitor ratings should be consulted on these aspects prior to design.
Push–pull circuits are less critical in general, since the ground referenced RF loops are practically eliminated, and the impedance levels are higher for a given power output. High power broadband transformers are also easier to de­sign than comparable LC matching networks.
8
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
Page 9
MRF154
Broadband RF Power MOSFET 600W, to 80MHz, 50V
M/A-COM Products
Released - Rev. 07.07
9
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions is considering for development. Performance is based on target specifications, simulated results, and/or prototype measurements. Commitment to develop is not guaranteed. PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology Solutions has under development. Performance is based on engineering tests. Specifications are typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available. Commitment to produce in volume is not guaranteed.
North America Tel: 800.366.2266 / Fax: 978.366.2266
Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Loading...