NXP Semiconductors BGA7210, Руководство пользователя

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UM10480 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
User manual Rev. 2 — 26 July 2011 7 of 13
NXP Semiconductors
UM10480
Variable gain amplifier BGA7210
6. BGA7210 evaluation
Remark: The RF evaluation board output is configured with a shunt capacitor to yield
optimal linearity at approximately 2 GHz. It is recommended that the shunt capacitor is
removed at other operating frequencies. Please refer to the BGA7210 data sheet for
performance information.
6.1 Calibration
The calibration port can be used to determine the PCB losses.
6.2 S-parameters and output compression point
Both S-parameters and the output compression point (P1 dB) are measured with a
NetWork Analyzer (NWA); see
Figure 4 .
The P1 dB is measured by sweeping the input power, and observing where the S21 of the
device is compressed by 1 dB compared to the linear gain. In order for this measurement
to accurately measure the input power, the input must first be calibrated with a power
head. The output power of the device is calculated using equation
Equation 1 .
(1)
The drive power can be optionally enhanced with a driver amplifier. To prevent the output
signal driving the NWA receiver into compression, an attenuator can be inserted at the
NWA input. Both driver amplifier and attenuator should be included in the calibration path.
In order to maintain small signal conditions for the S-parameter measurements, an input
power of

20 dBm is applied.
Fig 4. S-parameter and output compression power set-up
P
out
dBm
 
P
in
dBm
 
s
21
dB
 
+ =
019aac408
OPTIONAL
PRE-AMPLIFIER
POWER
SUPPLY
MMIC
DUT
PORT 1 PORT 2
2 PORT (or 4 PORT) NETWORK ANALYZER
OPTIONAL
ATTENUATOR