18.0-30.0 GHz GaAs Receiver
QFN, 7x7 mm
November 2006 - Rev 03-Nov-06
R1002-QB
App Note [1] Biasing - This device is operated with both stages in parallel, and can be biased for low noise performance or high
power performance. Low noise bias is nominally Vd=4.5V, Id=135mA and is the recommended bias condition. More controlled
performance will be obtained by separately biasing Vd1 and Vd2 each at 4.5V, 65mA. Power bias may be as high as Vd=5.5V,
Id=270mA with all stages in parallel, or most controlled performance will be obtained by separately biasing Vd1 and Vd2 each at 5.5V,
135mA. Attenuator bias,Vg3, can be adjusted from 0.0 to -1.2V with 0.0V providing maximum attenuation and -1.2V providing
minimum attenuation. Image reject mixer bias,Vg4, should nominally be -0.8V to minimize sensitivity of mixer performance to LO
level. 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 voltage needed
to do this is -0.5V.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.
MTTFTables
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
Temperature
55 deg Celsius
75 deg Celsius
95 deg Celsius
81 deg Celsius
101 deg Celsius
121 deg Celsius
-
6.77E+11
4.09E+10
3.29E+09
1.48E-03
2.44E-02
3.04E-01
65.0° C/W
-
Bias Conditions: Vd=3.0V, Id=135 mA
Backplate
Channel
Rth
MTTF Hours
FITs
Temperature
Temperature
55 deg Celsius
75 deg Celsius
95 deg Celsius
142 deg Celsius
162 deg Celsius
182 deg Celsius
-
4.11E+08
5.36E+07
8.35E+06
2.43E+00
1.87E+01
1.20E+02
58.9° C/W
-
Bias Conditions: Vd=5.5V, Id=270 mA
Page 5 of 10
Mimix Broadband, Inc., 10795 Rockley Rd., Houston,Texas 77099
Tel: 281.988.4600 Fax: 281.988.4615 mimixbroadband.com
Characteristic Data and Specifications are subject to change without notice. ©2006 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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