Product Overview
DS1302 DIP-8 RTC IC - 3-Wire Serial Interface, 31-Byte SRAM, 2V-5.5V, Arduino Compatible
Condition
Unused NOS. Sourced from an electronics distributor consolidating inventory. Unit is an 8-pin DIP marked DS1302 / 9927A3 / 480AB N - date code indicates week 27, 1999. Pins are straight with no oxidation. No damage or defects observed.
Ships same business day from our Idaho warehouse. Carefully packed.
Backed by our guarantee.
Product Overview
Dallas Semiconductor DS1302 real-time clock IC in an 8-pin DIP package. Tracks seconds, minutes, hours, day, date, month, and year with automatic leap-year correction through 2100. Includes 31 bytes of battery-backed non-volatile SRAM. Communicates via a 3-wire serial interface (RST, I/O, SCLK) and operates from 2V to 5.5V. Requires an external 32.768 kHz crystal and a battery backup - typically a 3V lithium coin cell - to maintain timekeeping and RAM contents when main power is off.
Key Features
- Package: 8-pin DIP (DS1302N) - through-hole, breadboard and PCB compatible
- Operating voltage: 2V to 5.5V
- Interface: 3-wire serial (RST, I/O, SCLK) - not I2C or SPI
- Non-volatile SRAM: 31 bytes, battery-backed
- Timekeeping: seconds, minutes, hours, day, date, month, year with leap-year correction to 2100
- External crystal required: 32.768 kHz
- Temperature range: -40°C to +85°C
- Date code 9927 - manufactured week 27, 1999
Applications
- Arduino, ESP32, and Raspberry Pi timekeeping projects
- Data loggers requiring timestamps and power-loss memory retention
- Embedded systems needing real-time clock and calendar functions
- DIY clocks, alarms, and schedulers in hobbyist and maker builds
- Industrial control systems requiring non-volatile time and date stamping
- Retro computing and vintage electronics restoration
Frequently Asked Questions
Does this use I2C or SPI?
Neither. The DS1302 uses its own 3-wire serial protocol with RST, I/O, and SCLK pins. Most Arduino and microcontroller libraries handle this in software - search for DS1302 libraries compatible with your platform before ordering if you have not used one before.
Is a crystal included?
No. The 32.768 kHz crystal is not included and must be sourced separately. Without it, the chip will not keep time.
Is a battery included?
No. A backup battery - typically a 3V CR2032 or similar lithium coin cell - is not included. Without battery backup, time and SRAM contents will be lost when main power is removed.
What package is this - DIP or SOIC?
This is the DIP-8 variant (DS1302N), confirmed by photo. Through-hole pins, breadboard-ready, approximately 8mm wide. Not the SOIC surface-mount version.
Is this compatible with Arduino?
Yes. The DS1302 is one of the most widely used RTC chips in Arduino and microcontroller projects. Numerous open-source libraries support it across Arduino, ESP32, AVR, ARM, and PIC platforms.
A 1999 date code on a chip that still knows what time it is - this one just needs a crystal, a coin cell, and something worth keeping track of.
