National Semiconductor Advanced Peripherals Real Time Clock Handbook 1989 contains the following Datasheets
TCP/RTC Family Comparisons
DP8570A Timer Clock Peripheral (TCP)
DP8571A Timer Clock Peripheral (TCP)
DP8572A Real Time Clock (RTC)
DP8573A Real Time Clock (RTC)
MM58274C Microprocessor Compatible Real Time Clock
MM58167A Microprocessor Real Time Clock
Application Notes
AN-353 MM58167A Real Time Clock Design Guide
AN-365 The MM58274C Adds Reliable Real-Time Keeping to Any Microprocessor System
AN-588 Calibration of the DP8570A Family
AN-589 DP8570A Timer Clock Peripheral Test Mode and Test considerations
AN-595 Flexible Timers on the DP8570A and DP8571A
AB-43 Typical DP8570A Interface to the IBM PC/XT for the Purpose of Engineering Evaluation