20-SOIC (0.295, 7.50mm Width) contains real time clocks.A Tape & Reel (TR) package is used to package time clock.Its supply voltage is 1.8V~4.2V.It is a Clock/Calendar type electrical real time clock.A part of this electronic RTC module is mounted in the way of Surface Mount.Electronic time clocks should be -40°C~85°C degrees Celsius during operation.Electronic time clocks are possible to guarantee Alarm, Leap Year, Square Wave Output, TCXO/Crystal, Watchdog Timer when operating.Transmission lines can be terminated with 20 terminations, which means that the RTC module that terminates the line matches its characteristic impedance.20 pins are present on it.PCF2129 are RTC s family.1.8V~4.2V is the supply voltage of this electrical digital time clock.The power supply is 2/4V.