RTC-4543SA Datasheet PDF - Seiko Epson Corp

Built in frequency adjusted 32.768 kHz crystal unit.
Interface type  :  3-wire serial interface
Operating voltage range :  2.5Vto5.5V
Wide Timekeeper voltage range :  1.4Vto5.5V
32.768 kHz frequency output function:  C-MOS output With Control Pin
The various functions include full calendar, timer, and low voltage detection.