MAX9930_09 Datasheet, PDF (14/16 Pages) Maxim Integrated Products – 2MHz to 1.6GHz 45dB RF-Detecting Controllers and RF Detector

2MHz to 1.6GHz 45dB RF-Detecting
Controllers and RF Detector
Waveform Considerations
The MAX9930–MAX9933 family of logarithmic amplifiers
respond to voltage, not power, even though input levels
are specified in dBm. It is important to realize that input
signals with identical RMS power but unique waveforms
result in different log amp outputs. Differing signal wave-
forms result in either an upward or downward shift in the
logarithmic intercept. However, the logarithmic slope
remains the same; it is possible to compensate for known
waveform shapes by baseband process.
It must also be noted that the output waveform is generat-
ed by first rectifying and then averaging the input signal.
This method should not be confused with RMS or peak-
detection methods.
Layout Considerations
As with any RF circuit, the layout of the MAX9930–
MAX9933 circuits affects performance. Use a short 50Ω
line at the input with multiple ground vias along the
length of the line. The input capacitor and resistor
should both be placed as close as possible to the IC.
V_CC should be bypassed as close as possible to the IC
with multiple vias connecting the capacitor to the
ground plane. It is recommended that good RF compo-
nents be chosen for the desired operating frequency
range. Electrically isolate RF input from other pins
(especially SET) to maximize performance at high
frequencies (especially at the high power levels of
the MAX9932).
Chip Information
PROCESS: High-Frequency Bipolar
Block Diagram
SHDN
V_CC
RFIN
LOG
DETECTOR
SET
GND
V-I*
MAX9930
MAX9931
MAX9932
OUTPUT-
ENABLE
DELAY
g_m
BLOCK
x1
BUFFER
SHDN
V_CC
RFIN
LOG
DETECTOR
OUTPUT-
ENABLE
DELAY
g_m
BLOCK
x1
BUFFER
MAX9933
V-I*
GND
*INVERTING VOLTAGE TO CURRENT CONVERTER.
OUT
C_CLPF
OUT
C_CLPF
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