This post explains for the Real Time Clock IC.
The Part Number is ISL12021.
The function of this semiconductor is Real Time Clock with On Chip Temp Compensation ±5ppm.
The Pinout: 14 LD TSSOP Type
Manufacturer: Intersil Corporation
Preview images :
The ISL12021 device is a low power real time clock with an embedded Temp sensor for oscillator compensation, clock/calendar, power fail, low battery monitor, brown out indicator, single periodic or polled alarms, intelligent battery backup switching and 128 bytes of battery-backed user SRAM.
A Real-Time Clock IC (RTC IC) is a specialized integrated circuit designed to keep track of time with a high degree of accuracy, even when the device it is used in is powered off. RTC ICs are commonly used in various electronic devices and systems that require accurate timekeeping and time-related functions.
The oscillator uses an external, low-cost 32.768kHz crystal. The real time clock tracks time with separate registers for hours, minutes, and seconds. The device has calendar registers for date, month, year and day of the week. The calendar is accurate through 2099, with automatic leap year correction.
1. Accurate Timekeeping: RTC ICs use highly accurate internal oscillators, often based on crystal resonators, to keep track of time. They can maintain timekeeping accuracy within seconds or even milliseconds per month, depending on the specific IC.
• Real Time Clock/Calendar
– Tracks Time in Hours, Minutes and Seconds
– Day of the Week, Day, Month and Year
• On-chip Oscillator Compensation Over the Operating Temp Range
: ±5ppm over -20°C to +70°C
• Day Light Saving Time
– Customer Programmable
• Separate FOUT pin
– 15 Selectable Frequency Outputs
• Utility Meters
• POS Equipment
• Medical Application
• Security Related Application
• Vending Machine
• White Goods
Other data sheets are available within the file: ISL12021IVZ, ISL12021CVZ, 2021IVZ, 12021CVZ