DS1302SN/T&R

Overview

The DS1302SN/T&R is a trickle-charge real-time clock (RTC) 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 the year 2100. The device features 31 bytes of battery-backed static RAM and communicates via a simple 3-wire serial interface (CE, I/O, SCLK). Operating on a supply voltage range of 2V to 5.5V, it consumes less than 300nA at 2.0V during timekeeping. The component is housed in an 8-SOIC package (0.209" width) and supports an industrial temperature range of -40°C to +85°C.

Feature Summary

• Real-time clock/calendar with automatic end-of-month adjustment and leap-year correction through 2100
• 31-byte battery-backed general-purpose static RAM for data retention
• Simple 3-wire synchronous serial interface compatible with most microcontrollers
• Programmable trickle charger for backup power source maintenance

Applications

• Clock and timing systems requiring low-power operation
• Data logging devices needing persistent timestamping
• Industrial control panels operating in wide temperature environments

Procurement Notes

Verify that the specific order suffix corresponds to the Tape & Reel (TR) packaging format as indicated in the product parameters. Confirm the industrial temperature grade (-40°C to +85°C) matches the system requirements, as commercial variants exist with different thermal limits. Ensure the 8-SOIC footprint dimensions align with the PCB layout specifications.

Selection Notes

Select this component when a microcontroller lacks dedicated hardware SPI or I2C peripherals, as the DS1302 utilizes generic GPIO pins for its 3-wire interface. Consider the internal pull-down resistors on CE, SCLK, and I/O pins during schematic design. Verify crystal load capacitance requirements (6pF typical) for accurate timekeeping performance.

Part Context

The DS1302 serves as the successor to the DS1202 RTC chip. It retains basic timekeeping functions while adding dual power pins for primary and backup supplies, a programmable trickle charger, and additional scratchpad memory. The 'SN' designation indicates the SOIC package variant, while the '/T&R' suffix specifies the reel-based packaging configuration.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.