7.5-25.0/15.0-50.0 GHz GaAs MMIC
Active Doubler
August 2007 - Rev 16-Aug-07
X1000-BD
App Note [1] Biasing
-
It is recommended to separately bias each doubler stage with fixed voltages of Vd(1,2)=5.0V, Vss=-5.0V and
Vg1=-0.6V. The typical DC currents are Id1=80mA, Id2=140mA and Iss=50mA. Vg2 can be used for active control biasing of Vd2, or it
can be left open and Vd2 will self bias at approximately 140mA. Maximum output power is achieved with Vss=-5.0V and Iss=50mA
but the device will operate with reduced bias to Vss=-2.0V and Iss=25mA. It is also recommended to use active biasing on Vd2 with
Vg2 to keep the currents constant as the RF power and temperature vary; this gives the most reproducible results. Depending on the
supply voltage available and the power dissipation constraints, the bias circuit may be a single transistor or a low power operational
amplifier, with a low value resistor in series with the drain supply used to sense the current. The gate of the pHEMT is controlled to
maintain correct drain current and thus drain voltage. The typical gate voltage for Vg2=-0.1V. Typically the gate is protected with
Silicon diodes to limit the applied voltage. Also, make sure to sequence the applied voltage to ensure negative gate bias is available
before applying the positive drain supply.
App Note [2] Bias Arrangement
-
For Individual Stage Bias (Recommended for doubler applications) -- Each DC pad (Vd1, 2, Vss and Vg1, 2) needs to have DC bypass
capacitance (~100-200 pF) as close to the device as possible. Additional DC bypass capacitance (~0.01 uF) is also recommended.
MTTF
1.0E+05
1.0E+04
MTTF (Years)
1.0E+03
1.0E+02
1.0E+01
Bias Conditions:
Vd1=Vd2=4.0V, Id1=40 mA, Id2=140 mA, Vss=-5.0V, Iss=50mA
1.0E+00
55
65
75
Temperature (°C)
MTTF is calculated from accelerated life-time data of single devices and assumes isothermal back-plate.
Bias Conditions: Vd1,2 = 5.0V, Id1,2 = 220 mA, Vss = -5.0V, Iss = 50 mA
85
95
Mimix Broadband, Inc., 10795 Rockley Rd., Houston, Texas 77099
Tel: 281.988.4600 Fax: 281.988.4615 mimixbroadband.com
Page 5 of 7
Characteristic Data and Specifications are subject to change without notice.
©2007
Mimix Broadband, Inc.
Export of this item may require appropriate export licensing from the U.S. Government. In purchasing these parts, U.S. Domestic customers accept
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