DATA S H E E T
HIGH POWER TRAVELING WAVE TUBE
FOR COMMUNICATIONS
LD7260
6 GHz, 2.25 kW CW, PPM FOCUSING, HIGH POWER GAIN
GENERAL DESCRIPTION
The NEC LD7260 is a PPM-focused traveling wave tube designed for use as final amplifiers in the earth-to-
satellite communications transmitter.
This is capable of delivering an output power of 2.25 kW over the range of 5.85 to 6.425 GHZ and provides a
power gain of 44 dB at rated output power. This is equipped with dual-stage depressed collector for enhancing
overall efficiency.
Furthermore, this is of rugged and reliable design offering long-life service.
FEATURES
™
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.
™
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.
™
Rugged Construction
The power gain 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.
™
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.
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. ET0478EJ1V0DS00
Date Published September 1999 M
Printed in Japan
©
1999
LD7260
GENERAL CHARACTERISTICS
ELECTRICAL
Frequency ……………………………………………… 5.850 to 6.425 GHz
Output Power ………………………………………… 2.25 kW
Heater Voltage ………………………………………… 6.3 V
Heater Current ………………………………………… 1.5 A
Type of Cathode ……………………………………… Indirectly heated, Impregnated
Cathode Warm-up Time …………………………… 180 s
MECHANICAL
Dimensions …………………………………………… See Outline
Weight ………………………………………………… 11 kg approx.
Focusing ……………………………………………… Periodic Permanent Magnet
Mounting Position …………………………………… Any
Electrical Connections ……………………………… AMP LGH 1I Receptacle
RF Connections
Input ………………………………………………… Type SMA Female
Output ……………………………………………… Mates with CPR-137F Flange
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 ………………………………………
Collector-1 Voltage …………………………………
Collector-1 Current …………………………………
Collector-2 Voltage …………………………………
Collector-2 Current …………………………………
Cathode Current ……………………………………
RF Drive Power ……………………………………
Load VSWR …………………………………………
ENVIRONMENTAL
Operating Temperature ……………………………
Storage Temperature ………………………………
Min.
–20
–62
Max.
+52
+80
Unit
˚C
˚C
Min.
6.0
–
–
180
12.0
–
9.0
–
4.0
–
–
–
–
Max.
6.6
5.0
5.0
–
16.0
25.0
11.0
600
6.0
925
1000
90
1.5 : 1
Unit
V
A
A
s
kV
mA
kV
mA
kV
mA
mA
mW
–
2
DATA SHEET ET0478EJ1V0DS00
LD7260
TYPICAL OPERATION (Note 2, 3, 4 and 5)
Unit
Frequency ……………………………………………
Output Power ………………………………………
Heater Voltage (Note 4) ……………………………
Heater Current ………………………………………
Helix Voltage ………………………………………
Helix Current ………………………………………
Collector-1 Voltage …………………………………
Collector-1 Current …………………………………
Collector-2 Voltage …………………………………
Collector-2 Current …………………………………
Cathode Current ……………………………………
Power Gain
Gain Variation
Gain Slope
at 225 W ………………………
at 2.25 kW ……………………
at 225 W ………………………
At 225 W
……………………
5.850–6.425
2.25
6.3
1.5
15.0
12
9.75
430
5.25
420
862
54
48
0.7
0.01
1.5
5.0
–29
GHz
W
V
A
kV
mA
kV
mA
kV
mA
mA
dB
dB
dB
dB/MHz
deg./dB
deg./dB
dBc
AM-PM Conversion
at 225 W ………………………
at 2.25 kW ……………………
3rd Order Intermodulation ………………………
(two equal carries, 225 W total)
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.
DATA SHEET ET0478EJ1V0DS00
3
LD7260
LD7260 OUTLINE
(Unit in mm)
No.8-32 UNC-2B X 7.6 DEEP MAX.
(4 PLACES)
135.6±0.8
No.8-32 UNC-2B X 6.35 DEEP MIN.
(4 PLACES-OPPOSITESIDE)
RF OUTPUT
CPR-137F FLANGE WITH
No.10-32 UNF-2B
THREADED HOLES
126.5±1
50.8
±
0.8
101.6
±
0.5
31.8
±
0.5
327.05 REF
108± 0.5
127
THERMAL SWITCH CONNECTOR
DEUTCH DN9601-3P
50.8±0.8
101.6±0.5
98.5±0.8
HANDLE
101.6
±
0.5
24.1 MAX.
76.2
17.5±0.8
19
185.6
±
1.5
203.2
±
0.5
176.3
76
±
13
304.8
±
0.5
406.4
±
0.5
416
±
5
560 MAX.
439
±
3
508
±
0.5
19
12.7
±
0.5
238.2
±
1
139.7
±
0.5
NO.6-32 UNC-2B
X 6.9 DEEP MIN.
(8 PLACE)
66.5
±
4
RF INPUT
TYPE SMA FEMALE
CAPTIVE FIXING SCREWS
No.8-32 UNC-2A (7 PLACE)
18.3±0.8
HELIX (GROUND)
M3 WITH NUTS
6.35±0.5
5.6±0.8
18.3±0.8
69.1±0.5
COLLECTOR-2
COLLECTOR-1
HEATER CATHODE
4 H.V. CONNECTOR
AMP LGH 1I RECEPTACLE
FOR 22.4 (0.88) ENGAGEMENT
HEATER
122
87.4±0.8
106.6±1.5
4
DATA SHEET ET0478EJ1V0DS00
165.1
±
1.5
127
LD7260
DATA SHEET ET0478EJ1V0DS00
5
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