DATA S H E E T
Document No. ET0476EJ1V0DS00 (1st edition)
Date Published September 1999 M
Printed in Japan
6 GHz, 400 W CW, CONDUCTION COOLING, HIGH POWER GAIN
HIGH POWER TRAVELING WAVE TUBE
FOR COMMUNICATIONS
LD7272 SERIES
The information in this document is subject to change without notice.
1999
For safe use of microwave tubes, refer to NEC document "Safety instructions to all personnel
handling electron tubes" (ET0048EJ
V
UM00)
GENERAL DESCRIPTION
The NEC LD7272 series of PPM focused traveling wave tubes are designed for final amplifier in the earth-to-
satellite communication's transmitter.
These are capable of delivering an output power of 400 W over the range of 5.85 to 6.45 GHZ and an output
power of 400 W over the range of 5.85 to 7.1 GHZ with a power gain of more than 49 dB at any power level.
Furthermore, these are rugged and reliable design offering long life services.
FEATURES
TM Lightweight, Compact and Efficient
The tube has dual-depressed collectors and designed to operate at high efficiency across the power output
range. It features state-of-the-art techniques to optimize size and efficiency.
TM Low Distortion
Distortion is a very important factor in multiplex digital signals transmission. NEC has developed techniques
for the correction of non-linear distortion and phase generated in a TWT. As a result, the TWT has an opti-
mum performance across a broad power range and is ideally suited for multi-carrier transmission systems.
TM Simple Cooling System
The tube is conduction cooled, so that the cooling system is simplified.
TM Rugged Construction
The power gain is designed to be rugged, therefore it is suitable for transportable systems.
TM Long Life and High Stability
The tube employs an advanced impregnated cathode with a low operating temperature for long life.
TM Micro-discharge 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.
LD7272 SERIES
2
DATA SHEET ET0476EJ1V0DS00
GENERAL CHARACTERISTICS
ELECTRICAL
Frequency ...................................................... 5.85 to 6.45 GHz
5.85 to 7.1 GHz
Output Power ................................................ 400 W
Heater Voltage ................................................ 6.3 V
Heater Current ................................................ 1.6 A
Type of Cathode ............................................. Indirectly heated, Impregnated
Cathode Warm-up Time
................................. 180 s
MECHANICAL
Dimensions ................................................... See Outline
Weight ......................................................... 3.2 kg approx.
Focusing
...................................................... Periodic Permanent Magnet
Mounting Position .......................................... Any
Electrical Connections .................................... Flying Leads
RF Connections
Input ......................................................... SMA Female
Output ...................................................... CPR-137 Flange
Cooling ......................................................... Conduction
ABSOLUTE RATINGS (Note 1, 2 and 3 )
ELECTRICAL
Min.
Max.
Unit
Heater Voltage .............................................
6.0
6.6
V
Heater Surge Current
.................................
3.0
A
Heater Current .............................................
2.2
A
Heater Warm-up Time .................................
180
s
Helix Voltage
.............................................
8.5
9.2
kVdc
Helix Current
.............................................
15.0
mAdc
Collector-1 Voltage .......................................
4.2
5.5
kVdc
Collector-1 Current .......................................
175
mAdc
Collector-2 Voltage .......................................
2.0
3.2
kVdc
Collector-2 Current .......................................
310
mAdc
RF Drive Power ..........................................
5
dBm
Load VSWR ................................................
1.5 : 1
ENVIRONMENTAL
Min.
Max.
Unit
Heat Sink Temperature .................................
40
+105
C
Ambient Temperature
Storage ......................................................
50
+85
C
LD7272 SERIES
3
DATA SHEET ET0476EJ1V0DS00
TYPICAL OPERATION (Note 2, 3, 4 and 5)
Unit
Frequency ...................................................
6.15
GHz
Output Power .............................................
432
W
Heater Voltage (Note 4)
..............................
6.3
V
Heater Current .............................................
1.55
A
Collector-1 Voltage .......................................
4.5
kVdc
Collector-1 Current .......................................
146
mAdc
Collector-2 Voltage .......................................
2.88
kVdc
Collector-2 Current .......................................
143
mAdc
Cathode Current ..........................................
294
mAdc
Helix Voltage
.............................................
9.0
kVdc
Helix Current
.............................................
3.6
mAdc
Power Gain
at (SSG) ...........................
57.2
dB
at (LSG) ...........................
52.7
dB
Gain Variation
at 40 W ...........................
1.5
dB/600MHz
Gain Slope
at 40 W ...........................
0.015
dB/MHz
AM-PM Conversion
at 40 W ...........................
0.9
deg./dB
at 400 W ...........................
1.4
deg./dB
3rd Order Intermodulation ...........................
26
dBc
(two equal carriers, 100 W total)
Spurious
...................................................
67
dBc
Noise Figure ................................................
25
dB
Overall Efficiency
.......................................
39
%
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.
LD7272 SERIES
4
DATA SHEET ET0476EJ1V0DS00
LD7272 series OUTLINE (Unit in mm)
LEAD COLOR
LEAD CONNECTIONS
LENGTH
BROWN
HEATER
460 mmMIN.
YELLOW
HEATER-CATHODE
460 mmMIN.
ORANGE
COLLECTOR-1
460 mmMIN.
BLUE
COLLECTOR-2
460 mmMIN.
GREEN
HELIX (GROUND)
460 mmMIN.
8
1.0
28
1
23
0.8
46.4
0.8
55
0.8
6
0.3
46 NOM.
61 NOM.
38
1
21
1.5
45.35
0.25
70.75
0.25
96.2
0.25
140.6
0.25
185
0.25
248.6
0.25
312
0.25
375.6
0.25
399.5
3
439
0.25
480
0.76
30.5 NOM.
55.88
1.52
56 NOM.
76.2
0.25
82
1.5
8
4.4
10
5
RF INPUT
TYPE SMA FEMALE
RF OUTPUT
CBR-137 FLANGE WITH
NO.10-32 UNF-2B THREADED HOLES
LD7272 SERIES
5
DATA SHEET ET0476EJ1V0DS00
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