Adafruit PCF8523 Real Time Clock Assembled Breakout Board

The Adafruit PCF8523 Real-Time Clock Breakout keeps track of time even when your microcontroller loses power, with battery backup, 3.3V/5V compatibility and support for Arduino, CircuitPython and Raspberry Pi. CR1220 battery not included.

This is a great battery-backed real time clock (RTC) that allows your microcontroller project to keep track of time even if it is reprogrammed, or if the power is lost. Perfect for datalogging, clock-building, time stamping, timers and alarms, etc. Equipped with PCF8523 RTC - it can run from 3.3V or 5V power & logic! Works great with an Arduino using Adafruit's RTC library, with CircuitPython or with a Raspberry Pi (or similar single board Linux computer) Please note: This product does not come with a CR1220 coin cell battery. We recommend you purchase a coin cell battery to use with this product. The PCF8523 is simple and inexpensive but not a high precision device. It may lose or gain up to 2 seconds a day. For a high-precision, temperature compensated alternative, please check out the DS3231 precision RTC. If you need a DS1307 for compatibility reasons, check out our DS1307 RTC breakout.

Features

* Battery-backed real time clock (RTC) with PCF8523 chip

* Maintains time during power loss or microcontroller reprogramming

* Compatible with 3.3V or 5V power and logic

* Works with Arduino, CircuitPython, Raspberry Pi and Linux single board computers

* Ideal for datalogging, clocks, time stamping, timers and alarms

* PCB and header included

* Breadboard compatible or connect via wires

* Two mounting holes for secure installation

* Provides timekeeping for 5+ years with coin cell battery

* Accuracy: may lose or gain up to 2 seconds per day

* Coin cell battery (CR1220) sold separately

Specifications

* Mounting holes are 2.2mm (0.086in) diameter, 25mm (0.98in) apart

* This board/chip uses I2C 7-bit address 0x68

* Dimensions: 25.5mm x 21.7mm x 4.8mm

* Weight: 1.2g

Revision History

* As of March 25, 2022, this board now may come with a PCB version that has HVSON or SOIC-8 chip package depending on what chip is available in the market. Both are identical functionality!

* As of Aug 30, 2017 we have updated the design to have an RC filter on the power supply to reduce accidental resetting if power drops too fast!

Resources

* Detailed guide

Package Contents

* 1x Adafruit PCF8523 Real Time Clock Assembled Breakout Board

CR1220 battery not included.