DS1305N+

Real Time Clock Overview

The DS1305N+ is a serial alarm real-time clock (RTC) manufactured by Analog Devices Inc./Maxim Integrated. It provides a full binary coded decimal (BCD) clock/calendar tracking seconds, minutes, hours, date, month, day of week, and year with leap-year compensation valid through 2100. The device includes 96 bytes of battery-backed NV RAM for data storage and features two programmable time-of-day alarms. It operates on a single supply voltage ranging from 2.0V to 5.5V and supports both SPI (Modes 1 and 3) and standard 3-wire serial interfaces. The component is housed in a 16-pin DIP package and is rated for an industrial temperature range of -40°C to +85°C.

Real Time Clock Feature Summary

• Full BCD Clock/Calendar with automatic month-end adjustments and leap-year correction valid up to the year 2100.
• Dual power supply architecture supporting primary (VCC1), secondary (VCC2), and battery (VBAT) inputs with programmable trickle charging.
• Flexible serial interface selectable via SERMODE pin for either SPI or standard 3-wire communication.
• Two independent programmable alarms capable of generating interrupts based on specific combinations of seconds, minutes, hours, and days.

Real Time Clock Applications

• Industrial systems requiring precise timekeeping across wide temperature variations.
• Data logging equipment utilizing the integrated 96-byte NV RAM for non-volatile storage.
• Battery-operated devices leveraging low standby current and backup switching capabilities.
• Microcontroller-based embedded systems interfacing via SPI or 3-wire protocols.

Real Time Clock Procurement Notes

Verify that the ordering suffix 'N' corresponds to the industrial temperature grade (-40°C to +85°C) rather than the commercial grade. Confirm RoHS compliance status as indicated by the '+' suffix in procurement channels. Ensure the selected package matches the 16-pin DIP form factor required by the target PCB layout.

Real Time Clock Selection Notes

Select the DS1305N+ when an industrial temperature range is mandatory for the application environment. Choose this model over commercial variants if the system requires operation below 0°C. Ensure the design accommodates the 16-pin DIP footprint and utilizes the VCCIF pin if interfacing with 3V logic levels in mixed-supply systems.

Real Time Clock Part Context

The DS1305N+ belongs to the DS1305 family of serial alarm RTCs. The 'N' designation specifically identifies the industrial temperature variant (-40°C to +85°C), distinguishing it from the commercial version (DS1305). The '+' suffix indicates lead-free/RoHS-compliant packaging. This part is distinct from other Maxim RTCs like the DS1307, which uses I2C instead of SPI/3-wire.

Real Time Clock Replacement Considerations

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