DS17485SN-5

Real Time Clock Overview

The DS17485SN-5 is a real-time clock (RTC) IC from the DS17x85 family, designed as a successor to the industry-standard DS12885. It provides a multiplexed byte-wide interface for accessing timekeeping and memory functions. The device operates with a primary supply voltage range of 4.5V to 5.5V or 2.7V to 3.7V. It features 4096 bytes of battery-backed nonvolatile SRAM, in addition to 114 bytes of general-purpose RAM. Key specifications include automatic leap year compensation through 2099, a 64-bit silicon serial number, and power-control circuitry for system wake-up capabilities.

Real Time Clock Feature Summary

• Multiplexed byte-wide address/data bus interface
• 4096 bytes of extended battery-backed NV SRAM plus 114 bytes general-purpose RAM
• Automatic date adjustment including leap year correction through 2099
• Power-control circuitry supporting system power-on via alarm or kickstart input
• 64-bit unique silicon serial number integrated into the device

Real Time Clock Applications

• Embedded systems requiring precise timekeeping
• Utility meters for data logging and billing cycles
• Security systems needing event timestamping
• Network hubs, bridges, and routers for synchronization

Real Time Clock Procurement Notes

Verify the specific suffix 'SN' against official manufacturer documentation to confirm package type and temperature range variations. Confirm RoHS compliance status as manufacturing statuses may vary by production batch. Ensure primary and auxiliary battery connections adhere to specified voltage limits to prevent reverse charging damage.

Real Time Clock Selection Notes

Select this component when a parallel multiplexed interface is required instead of serial alternatives like I2C or SPI. Ensure the design supports the 24-pin SOIC package footprint. Verify that the system can provide the necessary VBAT and VBAUX supplies for backup operations. Consider the 4KB SRAM capacity against application memory requirements compared to the 2KB or 8KB variants in the same family.

Real Time Clock Part Context

This part belongs to the DS17x85 series, which includes the DS17285 (2KB RAM), DS17485 (4KB RAM), and DS17885 (8KB RAM). These devices are successors to the DS12885/DS12887 standards. The 'S' indicates an SOIC package, while 'N' typically denotes a specific tape-and-reel or tube variation depending on the distributor's coding, though the datasheet primarily lists PDIP, SO, and TSOP options.

Real Time Clock Replacement Considerations

Direct functional substitutes within the same family include the DS17285SN-5+ (2KB RAM) and DS17885SN-5+ (8KB RAM). These parts share identical pinouts and interface protocols but differ in nonvolatile memory capacity. Verify that the replacement variant meets the specific storage requirements of the target application.