DS1315E-33+

Real Time Clock Overview

The DS1315E-33+ is a Phantom Time Chip combining a CMOS real-time clock and nonvolatile memory controller. It tracks hundredths of seconds, seconds, minutes, hours, day, date, month, and year with automatic leap year correction valid to 2100. Operating at +3.3V in the 0°C to +70°C range, it uses a 64-bit serial pattern recognition sequence for access. The device supports battery backup for external CMOS SRAM via VCCO and includes redundant battery inputs (BAT1, BAT2) for high-reliability applications.

Real Time Clock Feature Summary

• Integrated Real-Time Clock tracking time up to hundredths of seconds with automatic leap year correction.
• Nonvolatile Controller providing power management and write protection for external CMOS SRAM or ROM.
• Serial Interface using a unique 64-bit pattern recognition sequence for secure communication.
• Redundant Battery Support with dual inputs (BAT1, BAT2) for high-reliability systems.

Real Time Clock Applications

• Systems requiring precise timekeeping with nonvolatile data storage.
• High-reliability industrial equipment with redundant power sources.
• Embedded controllers needing isolated time and memory functions.

Real Time Clock Procurement Notes

Verify the package type matches the design requirements, as the DS1315 family includes 16-pin PDIP, 16-pin SO, and 20-pin TSSOP variants. Confirm the voltage suffix (+33 for 3.3V, +5 for 5V) and temperature grade (standard vs. industrial 'N') align with the system specifications before ordering.

Real Time Clock Selection Notes

Select the DS1315E-33+ specifically for 3.3V operation within the commercial temperature range (0°C to +70°C). For industrial temperatures (-40°C to +85°C), choose the DS1315EN-33+. Ensure the host interface can generate the required 64-bit serial pattern for chip enable.

Real Time Clock Part Context

This component belongs to the Maxim Integrated DS1315 Phantom Time Chip family. It integrates timekeeping and memory control functions into a single serial interface device, eliminating the need for separate RTC and NV RAM controllers in specific embedded architectures.

Real Time Clock Replacement Considerations

Direct pin-compatible replacements include other DS1315 variants such as DS1315N-33+ (16-pin PDIP) or DS1315S-33+ (16-pin SO), provided the package footprint and operating voltage/temperature ranges are compatible with the existing design.

Real Time Clock FAQ

How does the DS1315 handle access to its internal registers?

Access requires a specific 64-bit serial pattern recognition sequence on the Data In (D) pin. Until this pattern is matched, all accesses are directed to the external memory via the CEO pin.

What is the function of the VCCO pin?

VCCO is a switched supply output that provides uninterrupted power to external CMOS SRAM during main power failure, switching automatically from VCCI or the highest voltage battery input.

Does the DS1315 support 12-hour and 24-hour modes?

Yes, the hours register allows selection between 12-hour mode (with AM/PM indicator) and 24-hour mode via bit configuration.