DATA S H E E T HIGH POWER TRAVELING WAVE TUBE FOR COMMUNICATIONS LD7261 20 GHz, 250 W CW, PPM FOCUSING, HIGH POWER GAIN GENERAL DESCRIPTION The NEC LD7261 is a PPM-focused traveling wave tube designed for use as final amplifier in the earth-tosatellite communications transmitter. This is capable of delivering an output power of 250 W over the range of 18.0 to 21.7 GHz and provides a power gain of more than 40 dB at 250 W. Furthermore, it is rugged and reliable design offers long-life service. FEATURES ™ High Power Gain The power gain is typically 40 dB at 250 W level. ™ Simple Cooling System All the tubes are forced-air-cooled, so that the cooling systems are greatly simplified. ™ PPM Focusing The tube is PPM (Periodic Permanent Magnet) -focused, eliminating entirely the focusing power supplies and interlock circuits. ™ Rugged Construction The tube is designed to be rugged, therefore it is suitable for transportable systems. ™ Long Life and High Stability The tube employs an advanced impregnated cathode with a low operating temperature for long life. ™ Microdischarge Free The tube is carefully designed to be free from microdischarge in the electron gun for long term operation, therefore it is suitable for digital communication service. For safe use of microwave tubes, refer to NEC document “Safety instructions to all personnel handling electron tubes” (ET0048EJ∗V∗UM00) The information in this document is subject to change without notice. Document No. ET0397EJ1V0DS00 Date Published August 1998 M Printed in Japan © 1998 LD7261 GENERAL CHARACTERISTICS ELECTRICAL Frequency ……………………………………………… 18.0 to 21.7 GHz Output Power ………………………………………… 250 W Heater Voltage ………………………………………… 6.3 V Heater Current ………………………………………… 1.42 A Type of Cathode ……………………………………… Indirectly heated, Impregnated Cathode Warm-up Time …………………………… 300 s MECHANICAL Dimensions …………………………………………… See Outline Weight ………………………………………………… 6.0 kg approx. Focusing ……………………………………………… Periodic Permanent Magnet Mounting Position …………………………………… Any Electrical Connections ……………………………… Flying Leads RF Connections Input ………………………………………………… SMA Female Output ……………………………………………… Mates with WR-51 waveguide (see outline) Cooling ………………………………………………… Forced Air ABSOLUTE RATINGS (Note 1, 2 and 3 ) ELECTRICAL Heater Voltage ……………………………………… Heater Surge Current …………………………… Heater Current ……………………………………… Heater Warm-up Time …………………………… Helix Voltage ……………………………………… Helix Current ……………………………………… Anode Voltage ……………………………………… Anode Current ……………………………………… Collector Voltage …………………………………… Collector Current …………………………………… Cathode Current …………………………………… RF Drive Power …………………………………… RF Output Power ………………………………… Load VSWR ………………………………………… Min. 6.0 – – 300 9.5 – 8.0 – 4.0 – – – – – Max. 6.6 2.5 1.8 – 10.8 15.0 10.25 0.5 5.8 350 350 25 400 1.2 : 1 Unit V A A s kV mA kV mA kV mA mA mW W – Min. –40 195 Max. +110 – Unit ˚C kg/hour –40 –10 +80 +50 ˚C ˚C ENVIRONMENTAL Temperature at output Flange …………………… Air Flow ……………………………………………… Ambient Temperature Storage …………………………………………… Operation ………………………………………… 2 LD7261 TYPICAL OPERATION (Note 2, 3, 4 and 5) Unit Frequency …………………………………………… 20.0 GHz Output Power ……………………………………… 250 W Heater Voltage (Note 4) …………………………… 6.3 V Heater Current ……………………………………… 1.42 A Helix Voltage ……………………………………… 10.6 kV Helix Current ……………………………………… 0.7 mA Anode Voltage ……………………………………… 8.6 kV Anode Current ……………………………………… 0.01 mA Collector Voltage …………………………………… 5.0 kV Collector Current …………………………………… 264 mA Cathode Current …………………………………… 265 mA Power Gain at 25 W ……………………… 49 dB at 250 W ……………………… 46 dB Gain Variation at 25 W ……………………… 5 dB Gain Slope at 25 W ……………………… 0.012 dB/MHz AM-PM Conversion at 25 W ……………………… 1.5 deg./dB at 250 W ……………………… 6.0 deg./dB 3rd Order Intermodulation ……………………… (two equal carries, 25 W total) –30 dBc Note 1 : Absolute rating should not be exceeded under continuous or transient conditions. A single absolute rating may be the limitation and simultaneous operation at more than one absolute rating may not be possible. Note 2 : The tube body is at ground potential in operation. Note 3 : All voltages are referred to the cathode potential except the heater voltage. Note 4 : The optimum operating parameters are shown on a test performance sheet for each tube. Note 5 : These characteristics and operating values may be changed as a result of additional information or product improvement. NEC should be consulted before using this information for equipment design. This data sheet should not be referred to a contractual specification. 3 4 76.2 83 ± 0.5 Lead No. 1 2 3 4 5 6 (75.5 TYP.) Element Heater Heater-Cathode Anode Collector Helix (GROUND) Thermal Protection (Normal Close) Color Brown Yellow Blue Red Black White 19 101 ± 0.5 174 ± 1 101 ± 0.5 33 12.62 25.24 101 ± 0.5 179 ± 2 505 MAX. (500 TYP.) RF Input SMA Female 157 ± 0.5 900 ± 50 y t r e w q (110) 8-32 UNC-2B Threaded Holes 10 Pics. (For screw part) 108 MAX. 87.5 MAX. 83 ± 0.5 Cover Plate 55 ± 2 Air Output with Slit 19.8 ± 0.5 99 ± 1 98.5 87 ± 0.5 M3-4 Holes Air Inlet Interface RF Output WR-51 Waveguide 6-32 UNC-2B Thru 4 Pics. Air Inlet 23 10 Lead Connections 11.4 6.4 5.6 152 ± 0.5 31.8±0.5 25.4 50.8 ± 0.2 76.2 ± 0.5 127 165.1 ± 1.5 6-32 UNC-2B Threaded Holes 8 Pics. LD7261 LD7261 OUTLINE (Unit in mm) 91 ± 0.5 24.28 12.14 33 6 LD7261 5 LD7261 No part of this document may be copied or reproduced in any form or by any means without the prior written consent of NEC Corporation. NEC Corporation assumes no responsibility for any errors which may appear in this document. NEC Corporation does not assume any liability for infringement of patents, copyrights or other intellectual property rights of third parties by or arising from use of a device described herein or any other liability arising from use of such device. No license, either express, implied or otherwise, is granted under any patents, copyrights or other intellectual property rights of NEC Corporation or others. While NEC Corporation has been making continuous effort to enhance the reliability of its electronic components, the possibility of defects cannot be eliminated entirely. To minimize risks of damage or injury to persons or property arising from a defect in an NEC electronic component, customers must incorporate sufficient safety measures in its design, such as redundancy, fire-containment, and anti-failure features. NEC devices are classified into the following three quality grades: “Standard”, “Special”, and “Specific”. The Specific quality grade applies only to devices developed based on a customer designated “quality assurance program” for a specific application. The recommended applications of a device depend on its quality grade, as indicated below. Customers must check the quality grade of each device before using it in a particular application. Standard: Computers, office equipment, communications equipment, test and measurement equipment, audio and visual equipment, home electronic appliances, machine tools, personal electronic equipment and industrial robots Special: Transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster systems, anti-crime systems, safety equipment and medical equipment (not specifically designed for life support) Specific: Aircrafts, aerospace equipment, submersible repeaters, nuclear reactor control systems, life support systems or medical equipment for life support, etc. The quality grade of NEC devices is "Standard" unless otherwise specified in NEC's Data Sheets or Data Books. If customers intend to use NEC devices for applications other than those specified for Standard quality grade, they should contact an NEC sales representative in advance. Anti-radioactive design is not implemented in this product. Printed on recycled paper