DS1337U

Real Time Clock Overview

The DS1337U is an I2C serial real-time clock (RTC) IC manufactured by Analog Devices Inc./Maxim Integrated. It provides seconds, minutes, hours, day, date, month, and year information with leap-year compensation valid through 2100. The device operates within a supply voltage range of 1.8V to 5.5V for full functionality, while maintaining timekeeping at voltages as low as 1.3V. Key features include two programmable alarms, a programmable square-wave output defaulting to 32kHz, and an oscillator stop flag. It utilizes an I2C bus interface for data transfer and is housed in an 8-pin µSOP package.

Real Time Clock Feature Summary

• I2C Serial Interface supporting Standard (100kHz) and Fast (400kHz) modes
• Two programmable time-of-day alarms with interrupt capabilities
• Programmable square-wave output (1Hz, 4.096kHz, 8.192kHz, or 32.768kHz)
• Oscillator Stop Flag (OSF) for detecting crystal failure or power loss

Real Time Clock Applications

• Handheld devices such as GPS units, POS terminals, and MP3 players
• Consumer electronics including set-top boxes and digital recorders
• Office equipment like fax machines, printers, and copiers
• Medical devices such as glucometers and medicine dispensers
• Telecommunications infrastructure including routers, switches, and servers

Real Time Clock Procurement Notes

Verify the specific ordering suffix 'U' corresponds to the 8-pin µSOP package configuration. Confirm RoHS compliance status, as '+' denotes lead-free/RoHS-compliant devices while other suffixes may vary. Ensure the selected variant matches the required temperature range of -40°C to +85°C for industrial applications.

Real Time Clock Selection Notes

Select the DS1337U when an external 32.768kHz quartz crystal is preferred over the integrated crystal option found in the DS1337C. This model requires external components for the oscillator circuit but offers flexibility in crystal selection. Ensure the design supports the open-drain I/O requirements for SDA, SCL, INTA, and SQW/INTB pins with appropriate pull-up resistors.

Real Time Clock Part Context

The DS1337U belongs to the Maxim Integrated DS1337 family of serial real-time clocks. It shares core functionalities with variants like the DS1337S (SO package) and DS1337+ (DIP package). The 'U' suffix specifically identifies the micro-small outline package (µSOP), distinguishing it from the DS1337C which integrates the crystal internally in a 16-pin SO package.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material.