7) Enable the output powers of the RF signal generators.
8) Using the calibration results from step 4, set the
generator outputs to produce -30dBm into RFINA
and RFINB.
9) Verify that an output voltage at VOUTA and VOUTB
of approximately 1.3V is measured on the volt-
meters.
10) Verify that an output voltage at VOUTD of approxi-
mately 1V is measured on the voltmeter.
11) Adjust the signal-generator power levels up and
down to see a corresponding change in VOUTA,
VOUTB, and VOUTD.
Detailed Description
The MAX2016 EV kit is a fully assembled and tested
surface-mount PCB that evaluates the MAX2016 dual
logarithmic detector/controller. The RF inputs utilize
50Ω SMA connectors for convenient connections to test
equipment.
Individual Log Amps (VOUTA and VOUTB)
The MAX2016 uses two individual log amps to measure
the input power applied to RFINA and RFINB. These
amplifiers are normally configured in detector mode to
provide an output signal proportional to the applied
input power level. The individual log amp output can
also be operated in a controller mode, if desired, to
control an external device using the input power as the
control parameter.
Detector Mode
The MAX2016 EV kit is assembled with a 0Ω resistor for
R1 and R2. This sets the slope of the individual log amp
output signal to approximately 18mV/dB (RF =
100MHz). To increase the slope of either individual out-
put signals, VOUTA or VOUTB, increase the value of R1
or R2, respectively. For example, if a 40kΩ resistor is
used for R1, the slope for the VOUTA signal increases
to 36mV/dB.
Power-Controller Mode
For operation of either VOUTA or VOUTB in controller
mode, remove R1 or R2. A set-point voltage must then
be applied to the SETA or SETB inputs. Use a DAC, an
external precision voltage supply, or the internal refer-
ence output and resistor-divider string to apply the set-
point voltage to SETA or SETB. Operate SETA or SETB
at voltages between 0.6V and 1.6V. RFINA or RFINB
are connected to the RF source and the VOUTA or
VOUTB is connected to the gain-control pin of the sys-
tem under control.
In the power-controller mode (Figure 2), the DC voltage
at OUTA or OUTB controls the gain of the PA leading to
a constant output power level. (Note: Only one con-
troller channel is shown within the figure. Since the
MAX2016 is a dual controller/detector, the second
channel can be easily implemented by using the adja-
cent set of input and output connections).
Difference Amplifier (VOUTD)
Comparator
The MAX2016 integrates two comparators to monitor
the difference in power levels (gain) of the RFINA and
RFINB. By default, R4 and R5 are set to be 0Ω.
Therefore, CSETL and CSETH are connected to V
CC,
thus disabling the comparator operations. To enable
the comparator operations, R4 and R5 must be
removed. Load C16 and C17 with 0.1µF capacitors.
Use the reference voltage from the MAX2016 to gener-
ate two voltages through a resistor-divider network
(R7/R8 and R9/R10) to set the CSETH and CSETL trip
points. Alternately, R4, R5, and R7–R10 can be
removed and external voltages applied at CSETH and
CSETL to set the comparator trip points. Be sure to
observe the voltage limits specified in the MAX2016
data sheet.
The logic outputs at each comparator monitor the gain
independently. The COR output, (A + B), ORs the out-
puts of both comparators to tell whether the gain of the
amplifier falls in the range. For more information, refer to
the Applications Information section in the MAX2016
data sheet.
Evaluates: MAX2016
MAX2016 Evaluation Kit
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