DS1747-70IND

Real Time Clock Overview

The DS1747-70IND is a Y2K-compliant, nonvolatile timekeeping RAM integrating a real-time clock (RTC) and 512k x 8 static RAM. It operates on a single 5V supply within an industrial temperature range of -40°C to +85°C. The device features a parallel interface with a 70ns access time. RTC registers are mapped to the top eight RAM locations in BCD format, providing century, year, month, date, day, hours, minutes, and seconds data with automatic leap year compensation valid through 2100. An integrated lithium energy source ensures over 10 years of data retention without power.

Real Time Clock Feature Summary

• Integrated NV SRAM, RTC, crystal, power-fail control circuit, and lithium battery
• Y2K compliant with automatic leap year compensation valid up to 2100
• Standard JEDEC byte-wide 512k x 8 static RAM pinout
• Power-fail write protection allows for ±10% VCC power-supply tolerance

Real Time Clock Applications

• Industrial systems requiring precise timekeeping and nonvolatile storage
• Embedded controllers needing integrated calendar and memory functions
• Equipment requiring extended data retention during power outages

Real Time Clock Procurement Notes

Verify the specific package variant required, as the DS1747 series includes both standard DIP modules and PowerCap module boards. Confirm that the ordering suffix IND corresponds to the industrial temperature range (-40°C to +85°C). Ensure compatibility with the 32-pin EDIP package dimensions if using the standard DIP version. Check for lead-free compliance markings if RoHS standards are mandatory for the assembly process.

Real Time Clock Selection Notes

Select the DS1747-70IND when a 512k capacity is required alongside RTC functionality. Compare against other densities in the DS174x family for pin compatibility. Consider the PowerCap option if surface-mount assembly is preferred to protect the internal crystal and battery from reflow temperatures. Verify that the system can accommodate the 32-pin DIP footprint or the separate PowerCap board layout.

Real Time Clock Part Context

The DS1747 belongs to the Maxim Integrated DS174x family of Y2K-compliant nonvolatile timekeeping RAMs. This family offers various memory densities while maintaining pin-for-pin compatibility across different package styles. The DS1747 specifically provides the highest density (512k x 8) in this series, combining extensive storage with comprehensive timekeeping features in a single component.

Real Time Clock Replacement Considerations

Other members of the DS174x family offer pin-compatible alternatives with different memory capacities. Verify that the replacement part matches the required voltage level (5V vs 3.3V) and temperature range. If using a PowerCap module, ensure the separate battery/crystal unit is compatible with the selected base chip.