DS1302N

Overview

The DS1302N is a trickle-charge timekeeping chip manufactured by Analog Devices Inc./Maxim Integrated. It integrates a real-time clock/calendar and 31 bytes of battery-backed static RAM. The device communicates via a simple 3-wire serial interface (CE, I/O, SCLK) compatible with most microcontrollers. It supports 24-hour or 12-hour formats with leap-year compensation valid up to the year 2100. Operating on a supply voltage of 2.0V to 5.5V, it consumes less than 300nA at 2.0V during timekeeping. The industrial temperature grade version operates from -40°C to +85°C in an 8-pin DIP package.

Feature Summary

• Real-time clock/calendar counting seconds, minutes, hours, date, month, day of week, and year with leap-year compensation.
• 31 x 8 byte battery-backed general-purpose RAM for data storage.
• Simple 3-wire synchronous serial interface (CE, I/O, SCLK) supporting single-byte and burst mode transfers.
• Programmable trickle charger for backup battery or supercapacitor charging.

Applications

• Portable instruments requiring precise timekeeping.
• Telecommunication equipment and fax machines.
• Smart meters including multi-rate electricity meters and IC card water/gas meters.

Procurement Notes

Verify the specific suffix 'N' indicates the industrial temperature range (-40°C to +85°C). Confirm the package type matches the required 8-DIP form factor. Ensure the ordering suffix '+' denotes lead-free/RoHS compliance if required by assembly specifications. Check availability as distribution status may vary.

Selection Notes

Select the DS1302N when an industrial temperature range is required compared to the commercial DS1302. Ensure the system design accommodates the 3-wire serial interface constraints. Verify that the external 32.768kHz crystal meets the specified load capacitance of 6pF for accurate timing. Consider the trickle charger configuration if using a rechargeable backup source.

Part Context

The DS1302N is the industrial temperature grade variant of the DS1302 series. It serves as a successor to the DS1202, adding dual power pins and programmable trickle charging capabilities. The 'N' suffix specifically identifies the -40°C to +85°C operating range within the PDIP package lineup.

Replacement Considerations

Direct pin-compatible replacements include other DS1302 variants such as DS1302+ (commercial grade) or DS1302SN+ (industrial SOIC). Ensure the substitute maintains the 3-wire serial interface and voltage requirements.