DS1501WSN+

Real Time Clock Overview

The DS1501WSN+ is a Y2K-compliant real-time clock/calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It features a parallel interface, 256 bytes of NVSRAM, and operates within a voltage range of 3V to 3.6V at temperatures from -40°C to +85°C. The device provides automatic leap-year compensation up to the year 2100, programmable watchdog timers, alarms, and power-control circuitry. It utilizes a 32.768kHz crystal for timekeeping and includes battery backup capabilities with auxiliary input support.

Real Time Clock Feature Summary

• Y2K-compliant RTC with automatic leap-year correction valid until 2100
• 256-byte battery-backed NVSRAM with parallel byte-wide interface
• Programmable watchdog timer and day-of-week/date alarm functions
• Power-control circuitry supporting system wakeup via alarm or kickstart

Real Time Clock Applications

• Remote systems requiring precise timekeeping
• Battery-backed embedded systems
• Telecom switches
• Office equipment
• Consumer electronics

Real Time Clock Procurement Notes

Verify component authenticity through authorized distributors. Confirm RoHS compliance status as indicated by the '+' suffix. Check for specific revision errata on the manufacturer's website prior to integration. Ensure supply chain stability due to potential end-of-life status variations across channels.

Real Time Clock Selection Notes

Select this model for applications requiring a 3.3V parallel interface RTC with integrated memory. Ensure external crystal load capacitance matches the CS bit configuration (6pF or 12.5pF). Verify that system power sequencing accommodates the specified power-fail trip points and reset timing requirements.

Real Time Clock Part Context

This part belongs to the DS1501/DS1511 family of Y2K-compliant real-time clocks. The 'W' suffix denotes 3.3V operation in a TSOP package, while 'SN' indicates industrial temperature range (-40°C to +85°C) in a SOIC package. The '+' suffix confirms lead-free/RoHS compliance.

Real Time Clock Replacement Considerations

Direct pin-compatible replacements include other DS1501 variants with different voltage ratings (e.g., DS1501YN+ for 5V) or packages. Verify register compatibility and interface timing parameters when substituting with similar RTCs from the same manufacturer.

Real Time Clock FAQ

How does the DS1501WSN+ handle leap years?

The device automatically corrects for the number of days in each month, including leap year adjustments, valid up to the year 2100.

What is the function of the VBAUX pin?

The VBAUX pin serves as an auxiliary battery input to power kickstart and square-wave output features during main power loss, or can act as the primary backup source if VBAT is grounded.

Can the oscillator be stopped to save power?

Yes, the EOSC bit in the month register (05h) can be set to logic 1 to stop the oscillator, though it resets to 0 upon power-up.