XP1039-QJ_11 Datasheet, PDF (4/6 Pages) Mimix Broadband – 115.6-7.1 GHz Linear

5.6-7.1 GHz Linear 4W Power Amplifier
6x6mm QFN
January 2011 - Rev 06-Jan-11
P1039-QJ
App Note [1] Biasing – As shown in the Pin Designations table, the device is operated by biasing Vd1,2 at 8.0V. The nominal drain currents are
Id1=466mA and Id2=933mA, and this ratio of 1:2 between the first and second stage drain currents should be maintained for whatever drain
current levels are used. The typical gate voltages needed are -0.7V. Make sure to sequence the applied voltage to ensure negative bias is available
before applying the positive drain supply.
For linear applications it is recommended that active bias be used to keep the currents known and constant, and to maintain the best performance
over temperature. 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.
For applications where the device is running into saturation, high power levels will be achieved by fixing the drain currents at the nominal levels
with NO RF applied, and then operated with a fixed gate bias once RF is applied.
App Note [2] PWB Layout Considerations - It is recommended to provide 100pF decoupling capacitors as close as possible to the pins of the
device, with additional larger decoupling capacitors further away. For example, in the Recommended Layout shown below, there are 100pF 0402
capacitors placed very near the device pins, and 1uF 0805 capacitors placed further away (the gate line shown without a 1uF capacitor (pin 6)
would have this capacitor further away on the other side of the screw).
Thermal management of the device is essential. It is recommended that measures such as copper-filled vias under the package, and post/screws for
top to bottom heat transfer are used (see Recommended Layout shown below). Adequate heat-sinking under the PWB is necessary in maintaining
the package base at a safe operating temperature.
App Note [3] Power Detector - As shown in the schematic at right, the power
detector is implemented by providing +5V bias and measuring the difference in
output voltage with standard op-amp in a differential mode configuration.
Recommended Layout
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Characteristic Data and Specifications are subject to change without notice. ©2011 Mimix Broadband, Inc.
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