ADC driver in a 3×3 mm QFN — what the package tells you
The LTC6401CUD-8#PBF is an ADC driver from Analog Devices, designed to condition analog signals before conversion in data-acquisition chains. It comes in a 16-WFQFN exposed-pad package (3×3 mm body), which means the thermal pad underneath is the primary heat path — the PCB land pattern must include a via array to the ground plane to keep junction temperatures under control at higher supply currents.
Sibling variants for bandwidth matching
The LTC6401 family includes several speed grades — the -8, -20, and -26 suffixes denote different gain-bandwidth or slew-rate options. The LTC6401CUD-20#PBF and LTC6401CUD-26#PBF are the closest functional peers, sharing the same package and pinout. If the -8 variant's bandwidth does not meet the ADC's sampling-rate requirement, one of the higher-speed siblings may be the correct fit without a board respin.