The section "Programming the Fractional N- Synthesizer" in the MAX2121 datasheet on sheets 16 and 17 can serve as a reference for the MAX2112.
MAX2121
Recommended for New Designs
The MAX2121 low-cost, direct-conversion tuner IC is designed for satellite set-top and VSAT applications. The device directly converts the satellite signals...
Datasheet
MAX2121 on Analog.com
MAX2121B
Production
The MAX2121B low-cost, direct-conversion tuner IC is
designed for satellite set-top and VSAT applications.
The device directly converts the satellite...
Datasheet
MAX2121B on Analog.com
MAX2112
Not Recommended for New Designs
The MAX2112 low-cost, direct-conversion tuner IC is designed for satellite set-top and VSAT applications. The IC is intended for 8PSK and Digital Video...
Datasheet
MAX2112 on Analog.com