C1 couples the RF input signal to the detector input RFIN
which is referenced to VCC. C2 is the peak detector
capacitor connected between PCAP and VCC. The value of
C2 will affect the slew rate and bandwidth. Typically C1 can
equal C2. Ceramic capacitors are recommended for C1
and C2. The values for C1 and C2 are dependent on the
operating RF frequency. The capacitive reactance should
be less than 5W to minimize ripple on C2.