DS1305EN+

Real Time Clock Overview

The DS1305EN+ is a serial alarm real-time clock (RTC) in a 20-pin TSSOP package, rated for industrial temperatures (-40°C to +85°C). It provides binary coded decimal (BCD) timekeeping including seconds, minutes, hours, date, month, day of week, and year with leap-year compensation through 2100. The device includes 96 bytes of battery-backed NV RAM and two programmable time-of-day alarms. It operates on a single supply voltage from 2.0V to 5.5V and supports both SPI (Modes 1 and 3) and standard 3-wire serial interfaces via the SERMODE pin.

Real Time Clock Feature Summary

• Full BCD clock/calendar with leap-year compensation valid up to 2100
• 96-byte battery-backed nonvolatile RAM for data storage
• Dual power supply pins (VCC1, VCC2) with optional trickle charge output for backup sources
• Supports SPI Modes 1/3 or 3-wire interface with burst mode access

Real Time Clock Applications

• Industrial systems requiring precise timekeeping in wide temperature ranges
• Data logging applications utilizing the 96-byte NV RAM
• Systems needing dual-power redundancy with supercapacitor or rechargeable battery backup

Real Time Clock Procurement Notes

Verify the ordering suffix 'EN+' confirms the -40°C to +85°C industrial temperature range and lead-free/RoHS compliance. Confirm the 20-pin TSSOP package matches the design footprint. Ensure the specific revision of the datasheet aligns with the manufactured lot, as electrical characteristics may vary slightly between revisions.

Real Time Clock Selection Notes

Select this component when an industrial temperature range is required alongside SPI or 3-wire connectivity. The DS1305EN+ differs from the commercial variant (DS1305E+) by its extended temperature rating. Ensure the system logic voltage is compatible with the VCCIF pin if interfacing with 3V logic while operating at higher primary supply voltages.

Real Time Clock Part Context

The DS1305 series is part of Analog Devices' (formerly Maxim Integrated) line of serial RTCs. The 'EN+' designation specifically identifies the industrial grade version in the 20-pin Thin Shrink Small Outline Package (TSSOP). This distinguishes it from the DIP package variants and the commercial temperature range versions within the same functional family.

Real Time Clock Replacement Considerations

Direct pin-compatible replacements include other DS1305 variants such as DS1305N (DIP, industrial) or DS1305E (TSSOP, commercial), provided the temperature requirements are met. Cross-family replacements require verification of interface compatibility and register mapping.