DS1338U-18+

Real Time Clock Overview

The DS1338U-18+ is a low-power serial real-time clock (RTC) and calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It features 56 bytes of battery-backed NV SRAM and communicates via an I2C interface. The device operates with a supply voltage range of 1.71V to 5.5V and includes automatic power-fail detection for seamless switching to a backup supply. Key electrical parameters include a maximum standby current of 100µA at 1.89V, a VBAT input range of 1.3V to 3.7V, and operation within an industrial temperature range of -40°C to +85°C.

Real Time Clock Feature Summary

• Full BCD clock/calendar with leap-year compensation valid up to the year 2100
• 56-byte battery-backed general-purpose RAM with unlimited write cycles
• Built-in power-fail detect and switch circuitry for continuous timekeeping
• Programmable square-wave output signal (1Hz, 4kHz, 8kHz, or 32kHz)

Real Time Clock Applications

• Handheld devices such as GPS units and POS terminals
• 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 and servers

Real Time Clock Procurement Notes

Verify that the component matches the specific 8-pin µSOP package configuration required for the design. Confirm that the ordering suffix indicates lead-free and RoHS compliance. Ensure the primary supply voltage requirements align with the 1.71V minimum threshold specified for this variant before finalizing procurement.

Real Time Clock Selection Notes

Select the DS1338U-18+ when a low-voltage operation starting at 1.71V is required. This variant is distinct from the DS1338U-3+ which requires a higher minimum voltage. Consider the 8-pin µSOP package for space-constrained surface-mount designs. Verify that the system can accommodate the external 32.768kHz crystal connected to the X1 and X2 pins.

Real Time Clock Part Context

This component belongs to the DS1338 family of serial real-time clocks. The 'U' designation identifies the 8-pin µSOP package, while the '-18+' suffix specifies the 1.71V minimum operating voltage and lead-free/RoHS-compliant construction. Other variants in the series include different voltage thresholds and package types such as the SOIC-8 and 16-pin SOIC.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.