DS1302S

Overview

The DS1302S is a real-time clock/calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It provides seconds, minutes, hours, date, month, day of the week, and year information with leap-year compensation valid up to 2100. The device features a simple 3-wire serial interface compatible with TTL logic at VCC = 5V. It includes 31 bytes of battery-backed static RAM for general-purpose data storage. Operating on a supply voltage range of 2V to 5.5V, it supports low-power timekeeping with current consumption less than 300nA at 2.0V. The component is housed in an 8-SOIC package.

Feature Summary

• Real-time clock/calendar with automatic leap-year compensation
• 31-byte battery-backed static RAM
• Simple 3-wire serial interface (CE, I/O, SCLK)
• Low power operation: <300nA at 2.0V

Applications

• Portable instruments requiring precise timekeeping
• Data logging systems needing non-volatile memory
• Battery-powered embedded devices

Procurement Notes

Verify the specific suffix against the manufacturer's ordering table to confirm temperature grade and package dimensions. The 'S' designation indicates an 8-pin SO package with 208 mil width. Confirm RoHS compliance status based on the '+' suffix if required. Check lead times as availability may vary by distributor.

Selection Notes

Select this component when a low-cost, low-power RTC with integrated RAM is needed. Ensure the microcontroller supports synchronous serial communication via three pins. Verify that the operating temperature range of 0°C to +70°C meets system requirements; otherwise, consider industrial grade variants like DS1302SN+.

Part Context

The DS1302 series serves as a successor to the DS1202, adding dual power pins and programmable trickle charging capabilities. It is widely used in applications where space is limited and minimal pin count is preferred. The device simplifies interfacing by handling all timekeeping functions internally.

Replacement Considerations

Direct replacements include other DS1302 variants such as DS1302N+ (DIP-8) or DS1302Z+ (SO-8 150 mil). Industrial temperature versions are DS1302SN+ and DS1302ZN+. Ensure pin compatibility and software register mapping remain identical across these variants.