The Maxim Integrated MAX7419EUA+ is a 5th-order Bessel low-pass switched-capacitor filter in an 8-uMAX/uSOP surface-mount package. The Bessel response preserves group-delay flatness through the passband, so a 20 kHz audio signal passes with minimal phase distortion — useful when you need the waveform shape intact, not just the amplitude.
It will not run from 3.3 V, so if your board is all 3.3 V logic, you need a separate 5 V supply or a different filter. The 45 kHz cutoff is set by an internal clock divided from an external capacitor — no external resistor tuning, but the clock-to-cutoff ratio is fixed, so the accuracy depends on that capacitor tolerance.
Housed in an 8-TSSOP or 8-MSOP (0.118", 3.00 mm width) package, the MAX7419EUA+ is a compact surface-mount part for dense PCBs. The supplier device package is 8-uMAX/uSOP. It ships in Tube form — not Tape & Reel, so factor that into your pick-and-place planning if you are ordering production quantities.