36.0-42.0 GHz GaAs Transmitter
SMT, 7x7 mm
April 2009 - Rev 15-Apr-09
U1006-QB
App Note [1] Biasing
- App Note [1] Biasing - The device is operated by biasing VD=4.0V with ID=240mA. Additionally, a mixer and doubler
bias are also required with VG2 = -0.5V. Adjusting Vg2 above or below this value can adversely affect conversion gain, image rejection and
intercept point performance. The VC bias pin controls an integrated attenuator where VC=-1.3 V provides the minimum attenuation and
VC = 0.0 V provides the maximum attenuation (approximately 25 dB).
It is 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 VG1= -0.4V.
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.
MTTF
MTTF is calculated from accelerated life-time data of single devices and assumes an isothermal back-plate.
XU1006-QB, MTTF (yrs) vs. Backplate Temperature (°C)
1.0E+05
1.0E+04
MTTF (Years)
1.0E+03
1.0E+02
1.0E+01
1.0E+00
55
65
75
Temperature (°C)
85
95
Bias Conditions:
Vd=4.0V, Id=240 mA
Typical Application
RF OUT
37.0-39.5 GHz
XP1005
XU1006-QB
Coupler
IF In
2 GHz
Mixer
X
Buffer
X2
LO(+2.0dBm)
17.5-18.75 GHz (USB Operation)
19.5-20.75 GHz (LSB Operation)
Mimix Broadband MMIC-based 35.0-45.0 GHz Transmitter Block Diagram
(Changing LO and IF frequencies as required allows design to operate as high as 42 GHz)
Mimix Broadband's 36.0-42.0 GHz XU1006-QB GaAs Transmitter can be used in saturated radio applications and linear modulation
schemes up to 128 QAM. The transmitter can be used in upper and lower sideband applications from 36.0-42.0 GHz.
Mimix Broadband, Inc., 10795 Rockley Rd., Houston, Texas 77099
Tel: 281.988.4600 Fax: 281.988.4615 mimixbroadband.com
Page 7 of 9
Characteristic Data and Specifications are subject to change without notice.
©2009
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
their obligation to be compliant with U.S. Export Laws.
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