The key to electromagnetic interference (EMI) emission and electromagnetic susceptibility (EMS) lies in the selection of analog and logic active devices. It is essential to note the inherent sensitive characteristics and electromagnetic emission characteristics of active devices.
Active devices can be categorized into tuned devices and basic band devices. Tuned devices function as band-pass components, with frequency characteristics including: center frequency, bandwidth, selectivity, and out-of-band spurious response. Basic band devices act as low-pass components, with frequency characteristics including: cutoff frequency, passband characteristics, out-of-band suppression characteristics, and spurious response. Additionally, there are input impedance characteristics and balance-unbalance characteristics at the input terminals.
The sensitivity characteristics of analog devices depend on sensitivity (based on the device’s inherent noise) and bandwidth.
The sensitivity characteristics of logic devices depend on DC noise margin and noise immunity.
