20DBL0451 Datasheet, PDF (4/6 Pages) Mimix Broadband – 8.0-12.0/16.0-24.0 GHz GaAs MMIC Active Doubler

8.0-12.0/16.0-24.0 GHz GaAs MMIC
Active Doubler
April 2005 - Rev 01-Apr-05
20DBL0451
App Note [1] Biasing - It is recommended to separately bias each doubler stage Vd1 through Vd2 at Vd(1,2)=3.5V with Id1=25mA
and Id2=110mA. Separate biasing is recommended if the doubler is to be used at high levels of saturation, where gate rectification
will alter the effective gate control voltage. It is also recommended to use active biasing 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 voltages needed to do this are Vg1=-0.9V and Vg2=-0.3V. 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 -
n
For individual Stage Bias (Recommended for doubler applications) -- Each DC pad (Vd1, 2 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.
tio _{MTTFTables (TBD)}
c ^{These numbers were calculated based on accelerated life test information and thermal model analysis received from the fabricating foundry.}
Backplate
Channel
Rth
MTTF Hours
FITs
Temperature
55 deg Celsius
Temperature
deg Celsius
u_C/W
E+
E+
75 deg Celsius
95 deg Celsius
deg Celsius
deg Celsius
d^C/W
E+
C/W
E+
E+
E+
ro ^{Bias Conditions: Vd1=Vd2=3.5V, Id1=25 mA, Id2=110 mA}
-p
re
P
Mimix Broadband, Inc., 10795 Rockley Rd., Houston, Texas 77099
Tel: [phone] Fax: [phone] mimixbroadband.com
Page 4 of 6
Characteristic Data and Specifications are subject to change without notice. ©2005 Mimix Broadband, Inc.
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