NEC LD7249U, LD7249 Datasheet
DATA SHEET
HIGH POWER TRAVELING WAVE TUBE
FOR GROUND TERMINALS
LD7249 SERIES
14 GHz, 350 W/400 W CW, CONDUCTION COOLING, HIGH POWER GAIN
GENERAL DESCRIPTION
NEC LD7249 series of PPM-focused traveling wave tube are designed for use as final amplifiers in the earth-to-
satellite communications transmitter.
Two models of the LD7249 series are capable of delivering an output power of 350 W and 400 W over the range
of 13.75 to 14.5 GHz and provide a high power gain of more than 47 dB at the rated output power level.
Furthermore, this is of rugged and reliable design offering long-life service.
FEATURES
™ High Power Gain
The power gain is typically 54 dB at the rated output power level.
™
Simple Cooling System
The tube is conduction-cooled so that the cooling system is 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. ET0221EJ5V0DS00 (5th edition)
Date Published August 1999 M
Printed in Japan
©
1997
LD7249 SERIES
GENERAL CHARACTERISTICS
ELECTRICAL
Frequency ……………………………………………… 13.75 to 14.5 GHz
Output Power
LD7249 ……………………………………………… 350 W
LD7249U …………………………………………… 400 W
Heater Voltage…………………………………………6.3 V
Heater Current ………………………………………… 1.2 A
Type of Cathode ………………………………………Indirectly heated, Impregnated
Cathode Warm-up Time …………………………… 180 s
MECHANICAL
Dimensions ……………………………………………See outline
Weight ………………………………………………… 4 kg approx.
Focusing ……………………………………………… Periodic Permanent Magnet
Mounting Position …………………………………… Any
Electrical Connections ……………………………… Flying Leads
Heater, Heater-Cathode, (Optionally, the HV lead out let position can be changeable)
Helix, Collector-1, Collector-2
and Thermal Protection
RF Connections
Input ………………………………………………… Type SMA Female
Output ……………………………………………… Mates with UBR-120 Flange, Waveguide : WR-75
Cooling ………………………………………………… Conduction
ABSOLUTE RATINGS (Note 1, 2 and 3 )
ELECTRICAL
Heater Voltage……………………………………… 6.0 6.6 V
Heater Surge Current …………………………… – 3.0 A
Heater Current ……………………………………… 1.0 2.0 A
Heater Warm-up Time …………………………… 180 – s
Helix Voltage ……………………………………… 8.0 9.2 kV
Helix Current ……………………………………… 0 10 mA
Collector-1 Voltage………………………………… 4.0 4.6 kV
Collector-1 Current ………………………………… – 180 mA
Collector-2 Voltage ………………………………… 2.3 3.1 kV
Collector-2 Current ………………………………… – 290 mA
Cathode Current …………………………………… 200 290 mA
RF Drive Power …………………………………… – 5 mW
Load VSWR ………………………………………… – 1.5 : 1
MECHANICAL
Heat Sink Temperature …………………………… –40 +115 °C
ENVIRONMENTAL
Ambient Temperature
Storage …………………………………………… –50 +90 ˚C
Operating ………………………………………… –40 +100 ˚C
min. max. Unit
Min. Max. Unit
Min. Max. Unit
2
DATA SHEET ET0221EJ5V0DS00
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