Filter type and cutoff — what the 45 kHz Butterworth means for your signal chain
The MAX7420CUA+ is a 5th-order Butterworth low-pass switched-capacitor filter with a 45 kHz cutoff frequency. The Butterworth response delivers maximally flat passband gain — no ripple up to the corner — making it a clean choice for anti-aliasing or reconstruction in audio-bandwidth data-acquisition paths where amplitude flatness matters more than a sharp roll-off. Switched-capacitor architecture means the cutoff is set by an internal clock, so no external RC network is needed. The 45 kHz corner suits applications like ADC pre-filtering for signals up to about 20 kHz, leaving margin for the filter's transition band before aliasing components fold in.
Supply and package — board-fit constraints
Supplied in tube packaging. The 8-pin MSOP/TSSOP-compatible land pattern is widely supported; no special thermal pad or exposed paddle to route.