Microwave Diode and Capacitors - Cobham plc

Ceramic GaAs Hyperabrupt Tuning Varactor Diodes
The ML4572 and ML4580 Series of tuning varactors are hyperabrupt junction gallium arsenide devices. These
series off especially high “Q factors” (up to 4000) that permit excellent tuning performance from VHF to 40GHz.
With these devices, linear tuning of frequency with bias voltage can be achieved for VCOs with moderate tuning
bands using transistors, Gunns or IMPATTs as well as with tunable filters and amplifiers. These diodes are an
excellent choice for modulators applications where better linearity or nearly constant modulation sensitivity is
desired.
Specifications @ +25°C
Capacitance C T-4 (pF)
Type
Number Min. Typical Max
Total
Capacitance
Ratio
C TO /C TVB
Max.
Quality
Factory
Min.
Breakdown
Voltage
(V) Min.
Standard
Case Style
ML4572 0.40 0.57 0.74 5.5. 4000 25 96
ML4573 0.75 0.87 0.99 6.0 3500 25 96
ML4574 1.00 1.25 1.49 7.0 3000 25 96
ML4575 1.50 1.75 1.99 8.5 3000 25 96
ML4576 2.00 2.25 2.49 9.0 2500 25 96
ML4577 2.50 2.75 2.99 9.0 2500 25 96
ML4578 3.00 3.50 3.99 9.5 2000 25 96
ML4579 4.00 4.50 4.99 9.5 2000 25 30
ML4580 5.00 5.50 5.99 10.0 2000 25 30
Notes:
1. The capacitance law of the diode chip is of the form.
C (V R = 0.1V) = 2.75 pF
C (V R = 0.3V) = 2.6A pF
C (V R = 1.0V) = 1.85A pF Where A =
C (V R = 4.0V) = 0.485A pF
C (V R = 10V) = 0.30A pF
C d = total capacitance
C p = case capacitance
C (V R = 25V) = 0.26A pF
2. GaAs Hyperabrupt Tuning Varactors are available in alternative case styles as well as in chip form.
When ordering specify the desired case by adding the case designation as a suffix to the type number
for example ML4572-96.
Cobham MAL Ltd trading as Cobham Sensor Systems www.cobham.com/sensorsystems
© Cobham plc, 2010.
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