DS1687-5

Real Time Clock Overview

The DS1687-5+ is a standalone real-time clock (RTC) in an EDIP-24 package with an embedded lithium battery and crystal. It operates on a +5V supply (4.5V to 5.5V) within a commercial temperature range of 0°C to +70°C. The device features a multiplexed address/data bus interface, 242 bytes of battery-backed NV RAM, and Y2K-compliant timekeeping valid through 2099. Key capabilities include power-on control via alarm or kickstart, a 32kHz square-wave output, and a 64-bit silicon serial number.

Real Time Clock Feature Summary

• Integrated EDIP-24 package containing the RTC chip, 32.768kHz crystal, and lithium battery for self-contained operation.
• +5V operation with 242 bytes of non-volatile user RAM accessible via a multiplexed bus.
• Power-control circuitry supports system wake-up from date/time alarms or external key closures.
• Includes a 64-bit unique silicon serial number and century register for long-term accuracy.

Real Time Clock Applications

• Embedded systems requiring autonomous timekeeping
• Utility meters needing reliable data retention
• Security systems with alarm-based power management
• Network hubs, bridges, and routers

Real Time Clock Procurement Notes

Verify that the specific part number matches the required voltage and temperature grade. The 'DS1687-5' designation indicates a +5V operating device. Ensure the '+ suffix' is present if lead-free/RoHS compliance is mandatory for the assembly process. Confirm the EDIP-24 package dimensions fit the target PCB layout.

Real Time Clock Selection Notes

Select the DS1687-5+ when a self-contained solution with an integrated battery and crystal is preferred over discrete components. This model is suitable for +5V logic systems. For industrial temperature ranges (-40°C to +85°C), the DS1687-5IND+ variant should be selected instead. Verify that the host system can interface with the multiplexed address/data bus architecture.

Real Time Clock Part Context

The DS1687 series serves as a successor to the industry-standard DS1287 PC clock. While the DS1685 is the bare die/chip version, the DS1687 integrates the necessary passive components into a single encapsulated unit. This simplifies design by eliminating external crystal and battery sourcing requirements while ensuring factory-tested timekeeping reliability.

Real Time Clock Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should verify compatibility with existing BIOS implementations if replacing legacy DS1287 units, as the DS1687 maintains functional compatibility for original clock functions.