DATA S H E E T HIGH POWER TRAVELING WAVE TUBE FOR DBS GROUND TERMINALS LD7237 DBS Band, 400 W CW, PPM FOCUSING, HIGH POWER GAIN GENERAL DESCRIPTION NEC LD7237 is PPM-focused traveling wave tube designed for use as final amplifier in the earth-to-satellite communications transmitter. This is capable of delivering an output power of 400 W over the range of 17.3 to 18.1 GHz and provides a high power gain of 53 dB at 400 W output power. Furthermore, this is of rugged and reliable design offering long-life service. LD7237 is fully compatible with TH3694B. FEATURES ™ High Power Gain The power gain is typically 53dB at 400 W level. ™ Simple Cooling System The tube is 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 the 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. ET0159EJ2V1DS00 Date Published August 1998 M Printed in Japan © 1996 LD7237 GENERAL CHARACTERISTICS ELECTRICAL Frequency .................................................................................. 17.3 to 18.1 GHz Output Power ............................................................................ 400 W Heater Voltage ........................................................................... 6.3 V Heater Current ........................................................................... 1.4 A Type of Cathode ........................................................................ Indirectly heated, Impregnated Cathode Warm-up Time ........................................................... 300 s MECHANICAL Dimensions ................................................................................ See Outline Drawing Weight ........................................................................................ 6.0 kg approx. Focusing .................................................................................... Periodic Permanent Magnet Mounting Position .................................................................... Any Electrical Connections .............................................................. AMP 861647-8 multi-pin connector Heater, Heater-Cathode Helix, Anode, Collector and Thermal Protection RF Connections Input ................................................................................... Mates with SMA-Female Output ................................................................................ Mates with UBR-140 Flange Cooling ....................................................................................... Forced Air 2 LD7237 ABSOLUTE RATINGS (Note 1, 2 and 3) ELECTRICAL Min. Max. Unit Heater Voltage .................................................................. 6.0 6.6 V Heater Surge Current ...................................................... – 4.5 A Heater Current .................................................................. – 3.0 A Heater Warm-up Time ..................................................... 300 – s Helix Voltage .................................................................... 9.5 10.75 kV Helix Current .................................................................... – 15 mA Anode Voltage .................................................................. 8.55 10.25 kV Anode Current .................................................................. – 0.5 mA Collector Voltage .............................................................. 4.0 5.5 kV Cathode Current ............................................................... – 350 mA mW RF Drive Power ................................................................ – 25 Load VSWR ...................................................................... – 1.5 Min. Max. Temperature at output Flange ........................................ – 100 ˚C Air Flow ............................................................................ 195 – kg/hr Storage ..................................................................... –40 +80 ˚C Operation .................................................................. –10 +50 ˚C MECHANICAL Unit Ambient Temperature 3 LD7237 TYPICAL OPERATION (Note 2, 3 and 5) Unit Frequency ............................................................................... 17.3 to 18.1 GHz Output Power ......................................................................... 400 W Heater Voltage (Note 4) ........................................................ 6.3 V Heater Current ........................................................................ 1.4 A Helix Voltage ........................................................................... 10 kV Helix Current ........................................................................... 2 mA Anode Voltage ........................................................................ 9.5 kV Anode Current ........................................................................ 0.1 mA Collector Voltage .................................................................... 4.7 kV Cathode Current ..................................................................... 290 mA at small signal .................................................................. 58 dB at rated output power ..................................................... 53 dB Gain Variation at small signal ............................................... 2 dB/800 MHz Gain Slope at small signal .................................................... 0.01 dB/MHz at small signal .................................................................. 0.5 °/dB at rated output power ..................................................... 2.0 °/dB Power Gain AM-PM Conversion 3rd Order Intermodulation (two equal carriers, 40 W total) ...................................... –32 dBc Cooling Air Flow .................................................................... 195 kg/hr Pressure Drop ......................................................................... 650 Pa 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 refferred 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. 4 LD7237 900 ± 50 LD7237 OUTLINE (Unit in mm) 85 MAX. 29 AMP861647-8 MULTI-PIN CONNECTOR 157 101 178 4-M4 101 505 MAX. 210 MAX. RF INPUT SMA FEMALE 10- φ 6 101 175 RF OUTPUT Mates with UBR-140 FLANGE 6 110 MAX. 19 111 127 MAX. 55 PIN CONNECTION 87.5 MAX. 86 66 98 7 1 2 6 φ 3 5 4 AMP861647-8 CONNECTOR 4-M3 83 AIR OUTLET PIN ASSIGNMENT Pin No. LEAD NAME 1 HEATER / CATHODE 2 HEATER 3 COLLECTOR 4 THERMAL PROTECTION 5 OPEN (NO CONNECTION) 6 HELIX (GROUND) 7 ANODE NOTE THERMAL PROTECTION : N / C (Normally Closed) CONTACT 5 LD7237 6 LD7237 7 LD7237 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 Conponents, 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 Conponents, 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: Aircrafis, 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.