AI agents & screen readers: for a machine-readable, text-only catalogue, start at /llms.txt. Products are available as Markdown (/products.md, /products/{handle}.md) and JSON (/products.json, /products/{handle}.json).
Store

Adafruit

$10.40 |
In stock
No reviews yet

Keep track of time even when your project loses power or gets reprogrammed. This updated PCF8523 Real Time Clock breakout features STEMMA QT / Qwiic connecto...

Stock availability

Ready to ship from Sydney
2 in stock
Available with leadtime
100 available
Genuine AU stock · Ships from Sydney AU warranty GST tax invoice
Estimated Delivery
Arrives
Order within 3h 37m for same-day dispatch
Disclaimer
View Markdown
Secure checkout

Keep track of time even when your project loses power or gets reprogrammed. This updated PCF8523 Real Time Clock breakout features STEMMA QT / Qwiic connectors for solderless I2C wiring, plus traditional breadboard headers. It works with both 3.3 V and 5 V power and logic, making it compatible with virtually any microcontroller or SBC.

Works 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.

Key Features

  • PCF8523 RTC Chip – Battery-backed real-time clock with I2C interface
  • STEMMA QT / Qwiic Connectors – Solderless I2C connection, compatible with SparkFun Qwiic
  • 3.3 V and 5 V Compatible – Works with both power and logic levels
  • CR1220 Battery Backup – Keeps time for 5+ years on a coin cell (battery not included)
  • Breadboard Friendly – Header strip included for breadboard mounting
  • Two Mounting Holes – For permanent installation
Note: CR1220 coin cell battery and STEMMA QT cable are not included. 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.

Compatibility

  • Arduino (Adafruit RTClib library)
  • CircuitPython / Python
  • Raspberry Pi and other Linux SBCs
  • Any microcontroller with I2C support

Ideal For

  • Datalogging with accurate timestamps
  • Clock and alarm projects
  • Scheduled task execution
  • STEMMA QT / Qwiic I2C projects

Package Contents

  • 1× Adafruit PCF8523 Real Time Clock Breakout, fully assembled and tested
  • 1× Header strip for breadboard mounting

Resources

Jargon buster

Plain-language definitions for the technical terms used above.

breakout
A breakout board carries a small or fine-pitched component and brings its connections out to standard, breadboard- and header-friendly pins. Describing a part as a breakout means it can be wired into a project without soldering directly to the component's tiny contacts.
CircuitPython
A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.
Headers
Rows of connector contacts on a fixed pitch (commonly 2.54 mm) used to link a board to a breadboard, jumper wires, or another board. They come as male pin headers and female socket headers; when a module ships with pre-soldered headers it can be used straight away, whereas bare pads require soldering the pins yourself.
I2C
I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
microcontroller
A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.
Qwiic
Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
RTC
A Real-Time Clock keeps track of time even when the main processor is asleep or powered down, usually with a small backup battery. It matters for data logging and tracking projects that need accurate timestamps.
STEMMA
A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.
STEMMA QT
A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.

introducing adafruit stemma qt

Document · 1.5 MB · Click any page to view full size

Download PDF

adafruit pcf8523 real time clock

Document · 5.3 MB · Click any page to view full size

Download PDF

Related Tutorials

Free guides on learn.littlebird.com.au

Stella
Stella Expert

Ask me anything about this product

Maddy, co-founder of Little Bird

Need help? We're here for you!

Hi, I'm Maddy. My team and I are ready to help with your order or any questions.