Document
DATA S H E E T
HIGH POWER TRAVELING WAVE TUBE FOR COMMUNICATIONS
LD7235 SERIES
30 GHz, 150 W CW, CONDUCTION COOLING, HIGH POWER GAIN
GENERAL DESCRIPTION
The NEC LD7235 series of PPM-focused traveling wave tubes are designed for use as final amplifiers in the earth-to-satellite communications transmitter, LMDS (Local Multipoint Distribution Service) and other advanced communication systems. Three models of the LD7235 series are capable of delivering an output power of 150 W over the range of 26.5 GHz to 31.1 GHz and provide a high power gain of 50 dB at 150 W output power. These are equipped with dual-stage depressed collector for enhancing overall efficiency and a single collector. Furthermore, they are of rugged and reliable design offering long-life service.
FEATURES
™ High Power Gain The power gain is typically 50 dB at 150 W level. ™ Simple Cooling System The tubes are conduction-cooled, so that the cooling systems are greatly simplified. ™ PPM Focusing The tubes are PPM (Periodic Permanent Magnet) -focused, eliminating entirely the focusing power supplies and interlock circuits. ™ Rugged Construction The tubes are designed to be rugged, therefore they are suitable for transportable systems. ™ Long Life and High Stability The tubes employ an advanced impregnated cathode with a low operating temperature for long life. ™ Microdischarge Free The tubes are carefully designed to be free from microdischarge in the electron gun for long term operation, therefore they are 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. ET0215EJ3V0DS00 (3rd edition) Date Published August 1998 M Printed in Japan
©
1996
LD7235 SERIES
GENERAL CHARACTERISTICS
ELECTRICAL Frequency ……………………………………………… 26.5 to 28.6 GHz 27.5 to 30.0 GHz 30.0 to 31.3 GHz Output Power ………………………………………… 150 W Heater Voltage ………………………………………… 6.3 V Heater Current ………………………………………… 1.05 A Type of Cathode ……………………………………… Indirectly heated, Impregnated Cathode Warm-up Time …………………………… 300 s MECHANICAL Dimensions …………………………………………… See Outline Weight ………………………………………………… 3.5 kg approx. Focusing ……………………………………………… Periodic Permanent Magnet Mounting Position …………………………………… Any Electrical Connections ……………………………… Flying Leads RF Connections Input ………………………………………………… Mates with UG-599/U Flange Output ……………………………………………… Mates with UG-599/U Flange Cooling ………………………………………………… Conduction
ABSOLUTE RATINGS (Note 1, 2 and 3 )
ELECTRICAL Heater Voltage ……………………………………… Heater Surge Current …………………………… Heater Current ……………………………………… Heater Warm-up Time …………………………… Helix Voltage ……………………………………… Helix Current ……………………………………… 5 Isolated Anode Type Anode Voltage ……………………………………… Anode Current ……………………………………… 5 Single Collector Type Collector Voltage …………………………………… Collector Current …………………………………… 5 Dual-s.