Datasheet LD7249U, LD7249 Datasheet (NEC)

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

LD7249 SERIES

TYPICAL OPERATION (Note 2, 3 and 5)

LD7249 LD7249U Unit
Frequency ……………………………………………… 14.25 14.25 GHz
Output Power ………………………………………… 350 400 W
Heater Voltage (Note 4) ……………………………… 6.3 6.3 V
Heater Current ………………………………………… 1.2 1.2 A
Helix Voltage…………………………………………… 8.6 8.8 kV
Helix Current …………………………………………… 1.5 2.4 mA
Collector-1 Voltage …………………………………… 4.3 4.4 kV
Collector-1 Current …………………………………… 141 147 mA
Collector-2 Voltage …………………………………… 2.7 2.8 kV
Collector-2 Current …………………………………… 94 100 mA
Cathode Current ……………………………………… 237 250 mA
Power Gain at 20 W ……………………… 62 58 dB

at 350 W ……………………… 58 54 dB
Gain Variation at 20 W ……………………… 0.86 1.02 dB/750MHz
Gain Slope at 40 W ……………………… 0.006 0.006 dB/MHz
AM-PM ConversioN

Less than 100 W …………………………… 0.3 0.3 deg./ dB

at 350 W ……………………………………… 2.5 2.5 deg./ dB
3rd Order Intermodulation ………………………… –23 –24 dBc
(two equal carriers, 100 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 ET0221EJ5V0DS00

3

LD7249 SERIES

LD7249 OUTLINE (Unit in mm)

WITH 8. LENGTH 14
(8 SLOTS)

38±0.8

85 max.

76±1

55.9±0.8

22.4±0.2

47.8±0.2

RF OUTPUT
UBR-120 FLANGE

WITH No.6-32 UNC-2B
THREADED HOLES

77.2±1.3
60±0.8

43.5±0.3

11.5±1

431.8±0.8

416.1±0.2

352.6±0.2

289.1±0.2

225.6±0.2

162.1±0.2

φ

8 × 4.85
THRU

73.2±0.2

117.6±0.2

127±0.8

+0.1
–0.0

No.6-32 UNC-2B × 9 DEEP
BOTHSIDE

55.9±1

39.9±0.8

175±0.8

322.8±1.5

LEBEL

PARAMETER

LEBEL

IDENTIFICATION

+0.1

φ

10 × 5 THRU

–0.0

RF INPUT
SMA FEMALE

BeO

CAUTION

LEBEL

19±0.3 6±0.3

38±0.3

45.5±0.8

45.7±0.3
54±0.3

LEAD COLOR
BROWN
YELLOW
RED
BLUE
BLACK
BLUE (SLIM CABLE)
GREEN (SLIM CABLE)

4

DATA SHEET ET0221EJ5V0DS00

LEAD CONECTIONS
HEATER
HEATER-CATHODE
COLLECTOR-1
COLLECTOR-2
HILIX (GROUND)
THERMAL SWITCH-1
THERMAL SWITCH-2

57 max.

LENGTH

650 mm
650 mm
650 mm
650 mm
650 mm
650 mm
650 mm

LD7249 SERIES

DATA SHEET ET0221EJ5V0DS00

5

LD7249 SERIES

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“Standard”, “Special”, and “Specific”. The Specific quality grade applies only to devices developed based
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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.
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Anti-radioactive design is not implemented in this product.