Series 195 Octave-Band PIN Diode Attenuator/Modulator

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Application Notes for Microwave Attenuators 

SERIES 195

Series 195 current-controlled attenuator/modulators provide small size with greater than octave-bandwidth performance at low cost. All models except the 1950A* provide a minimum of 60 dB of attenuation with fall times of 20 nsec max, and rise times ranging from 25 nsec for the 1951 and 1952 to 125 nsec max for the 1956 and 1958. The 1950A* provides a minimum of 80 dB of attenuation with a fall time of 50 nsec max and a rise time of 250 nsec max. These characteristics make this series suitable for a wide range of applications including level setting, complex amplitude modulation, pulse modulation and high-speed switching. The eight models in the Series 195 encompass a frequency range from 0.5 to 18 GHz. All models except the 1950A* are capable of extended bandwidth operation, typically 3:1, with only moderate degradation in performance at the band edges.

As shown in figures 1 and 2 below, the RF circuit employed in all models except the Model 1950A* uses two shunt arrays of PIN diodes and two quadrature hybrid couplers. The quadrature hybrids are of a unique GMC microstrip design which are integrated with the diode arrays to yield a minimal package size. The RF circuit employed in the Model 1950A* uses one shunt array of PIN diodes with input and output impedance matching circuits.

*Model 1950A is a special-order product. Consult factory before ordering.

Models 1951-1958 RF schematic diagram

Model 1950A RF schematic diagram

 

  • Absorptive
  • Current controlled
  • 0.5 to 18 GHz frequency range
  • High performance MIC quadrature hybrid design
  • High speed

 

Series 195 Octave Band PIN Diode Attenuator/Modulator

 

MODEL FREQUENCY RANGE (GHz) MAX. INSERTION LOSS MAX. VSWR MAX. FLATNESS (± dB)
AT MEAN ATTENUATION LEVELS UP TO
10 dB 20 dB 40 dB 60 dB 80 dB
1950A* 0.5 - 1.0 1.4 2.0 0.3 0.8 1.7 2.2 3.2
1951 1.0 - 2.0 1.3 1.5 0.3 0.8 1.5 1.6  
0.75 - 2.25(1) 1.4 2.0 0.5 1.4 3.0 3.5
1952 2.0 - 4.0 1.5 1.5 0.3 0.8 1.5 1.6
1.5 - 4.5(1) 1.6 2.0 0.5 1.4 3.0 3.5
1953 2.6 - 5.2 1.7 1.6 0.3 0.8 1.5 1.6
1.95 - 5.85(1) 1.8 2.1 0.5 1.4 3.0 3.5
1954 4.0 - 8.0 2.0 1.7 0.3 0.8 1.5 1.6
3.0 - 9.0(1) 2.1 2.2 0.5 1.4 3.0 3.5
1955 5.0 - 10.0 2.2 1.7 0.5 0.9 1.5 1.6
3.75 - 11.25(1) 2.3 2.2 0.7 1.4 3.0 3.5
1956 6.0 - 12.0 2.3 1.8 0.7 1.0 1.5 1.6
4.5 - 13.5(1) 2.4 2.2 0.9 1.5 3.0 3.5
1958 8.0 - 18.0 2.5(2) 1.8(2) 0.7 1.0 1.5 1.6
6.0 - 18.0(1) 2.5(2) 1.8(2) 0.9 1.5 3.0 3.5

(1) Specifications for the extended frequency ranges are typical.
(2) Except from 16-18 GHz where Insertion loss is 3.5 dB max and VSWR is 2.0 max

*Model 1950A is a special-order product. Consult factory before ordering.

PERFORMANCE CHARACTERISTICS

Mean Attenuation Range
1950A* ..................... 80 dB
All other units ............. 60 dB
Monotonicity .............. Guaranteed
Phase Shift ................. See Application Note
Temperature Effects ... See Fig. 3
Power Handling Capability
   Without Performance Degradation
   1950A*,1951 ............ 10 mW cw or peak
   All other units ........... 100 mW cw or peak
          Survival Power (from -65°C to +25°C;
          see Fig. 4 for higher temperatures)
      All units ................. 1 W average 25W peak (1 µsec max pulse width)
Switching Speed
   Fall Time
     195OA* ..................... 50 nsec max(3)
     All other units ............... 20 nsec max(3)
   Rise Time
     195OA* ..................... 250 nsec max(3)
     All other units ............... 125 nsec max(3)
Bias Current for Maximum Attenuation
      195OA* ...................... 5 to 35 mA
      All other units .............. 15 to 70 mA
 
(3) For attenuation steps of 10 dB or more.

*Model 1950A is a special-order product. Consult factory before ordering.

Series 195 power derating factor diagram

Series 195 typical effects of temperature on attenuation
Fig 3—Series 195, typical effects of temperature on attenuation

OPTION (G09) ENVIRONMENTAL RATINGS
Operating Temperature
   Range
.....................................

-54°C to + 110°C
Non-Operating
   Temperature Range
..........

-65°C to + 125°C
Humidity .............................. MIL-STD-202F, Method 103B, Cond. B (96 hrs. at 95%)
Shock .................................... MIL-STD-202F, Method 213B, Cond. B (75G, 6 msec)
Vibration ............................... MIL-STD-202F, Method 204D, Cond. B (.06" double amplitude or 15G, whichever is less)
Altitude ................................. MIL-STD-202F, Method 105C, Cond. B (50,000 ft.)
Temp. Cycling ........................ MIL-STD-202F, Method 107D, Cond. A, 5 cycles
AVAILABLE OPTIONS
Option No.         Description
3 SMA female bias connector
7 Two SMA male rf connectors
10 One SMA male (J1) and one SMA female (J2) rf connector
64 SMC male bias connector
64A SMB male bias connector
 G09 Guaranteed to meet Environmental Ratings
G12 RoHS Compliant
G16 RoHS Plus REACH Compliant

 

DIMENSIONS AND WEIGHTS
Series 195 Attenuator/Modulator Dimensions and Weights
Dimensional Tolerances, unless otherwise indicated: .XX±.02; .XXX±.005