Datasheet

MAX2204
The MAX2204 has high input impedance to allow
for high-value resistive tapping from a power amplifier.
This coupling method is the lowest cost and lowest
power loss when used with an isolator. See Figure 2 for
the typical application circuit.
The MAX2204 input impedance over frequency is listed
in Table 1.
Layout
The MAX2204 is not particularly sensitive to the layout,
since it only needs 5dBm for maximum output voltage.
However, there are two areas that need attention: the
GND pin and the supply bypassing. The GND pin should
be connected to the PCB ground with a GND via as
close as possible, and the supply bypass capacitor
should be close to the part.
RF Power Detector
6 _______________________________________________________________________________________
Table 1. MAX2204 Input Impedance Over Frequency
P
IN
= -16dBm P
IN
= +5dBm
FREQUENCY (GHz)
REAL (Ω) IMAG (jΩ) REAL (Ω) IMAG (jΩ)
0.4 109.3 -556.5 120.0 -563.3
0.6 80.5 -369.0 91.0 -379.3
0.8 73.4 -300.3 80.8 -310.7
1.0 64.1 -260.2 75.6 -275.8
1.2 65.8 -216.4 79.9 -231.3
1.4 62.3 -194.9 64.4 -202.8
1.6 48.9 -177.5 53.9 -192.3
1.8 33.1 -157.4 39.9 -174.6
2.0 21.8 -142.2 25.9 -158.3
2.2 15.2 -131.2 18.3 -144.5
2.4 10.6 -116.8 10.6 -131.9
2.6 11.8 -99.8 10.6 -115.6
TO ANT
PA
OUTPUT
TO ADC
ISOLATOR
C
FILTER
PEAK
DETECT
BUFFER
BIAS
ENABLE
MAX2204
Figure 2. Typical Application Circuit Using Resistive Tapping
from a Power Amplifier