{"title":"Adafruit PCF8523 Real Time Clock Assembled Breakout Board","handle":"adafruit-pcf8523-real-time-clock-assembled-breakout-board","url":"/products/adafruit-pcf8523-real-time-clock-assembled-breakout-board","description":"Keep track of time even when your project loses power or gets reprogrammed. The PCF8523 Real Time Clock breakout is a battery-backed RTC that communicates over I2C and works with both 3.3 V and 5 V power and logic. Perfect for datalogging, clock building, time stamping, timers, and alarms.\n\nWorks with Arduino (using the Adafruit RTC library), CircuitPython, and Raspberry Pi or other single-board Linux computers. For higher precision (temperature-compensated), see the DS3231 Precision RTC. For DS1307 compatibility, see the DS1307 RTC Breakout.\n\nKey Features\n\n\nPCF8523 RTC Chip – Battery-backed real-time clock with I2C interface\n\n3.3 V and 5 V Compatible – Works with both power and logic levels\n\nCR1220 Battery Backup – Keeps time for 5+ years on a coin cell (battery not included)\n\nBreadboard Friendly – PCB and header included, plugs straight into a breadboard\n\nTwo Mounting Holes – For permanent installation\n\n\n\nNote: CR1220 coin cell battery is not included and must be purchased separately. The PCF8523 is not a high-precision device — it may lose or gain up to 2 seconds per day. For temperature-compensated accuracy, use the DS3231 Precision RTC.\n\n\nCompatibility\n\nArduino (Adafruit RTClib library)\nCircuitPython / Python\nRaspberry Pi and other Linux SBCs\nAny microcontroller with I2C support\n\n\nIdeal For\n\nDatalogging with accurate timestamps\nClock and alarm projects\nScheduled task execution\nTime-stamped sensor readings\n\n\nPackage Contents\n\n1× Adafruit PCF8523 Real Time Clock Breakout, assembled with header\n\n\nResources\n\n\nPCF8523 RTC Learn Guide – Code, libraries, schematics, and wiring diagrams\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":12441,"title":"Default Title","sku":"AF-3295","price":14.32,"on_sale":false,"in_stock":true,"available_quantity":100,"option1":"Default Title"}]}