1338C-18SRI

Overview

The Renesas Electronics Corporation 1338C-18SRI is a Real Time Clock (RTC) integrated circuit designed for clock and calendar applications. It features an I2C, 2-wire serial interface and includes embedded crystal functionality. The device provides 56 bytes of NVSRAM storage and supports leap year compensation. It operates with a supply voltage range of 1.8V to 5.5V and a battery backup voltage of 1.3V to 3.7V. The maximum current consumption is 2µA at 3.3V. The component is housed in a 16-SOIC package with dimensions of 0.295 inches by 7.50mm width. It supports time formats of HH:MM:SS in both 12/24 hour modes and date formats of YY-MM-DD-dd. The operating temperature range is -40°C to 85°C.

Feature Summary

• Integrated RTC with embedded crystal oscillator
• I2C serial interface for data communication
• 56-byte non-volatile SRAM storage capacity
• Automatic leap year compensation

Applications

• Clock and calendar systems requiring precise timekeeping
• Data logging applications needing timestamping
• Battery-powered devices requiring low standby current
• Industrial equipment operating in extended temperature ranges

Procurement Notes

This component is officially listed as obsolete and no longer manufactured by Renesas Electronics. Verification of availability should focus on distributor surplus stock or authorized replacement components. Buyers must confirm the specific suffix variants and ensure compatibility with existing PCB layouts when sourcing alternatives from other manufacturers such as Analog Devices.

Selection Notes

Engineers selecting this part should note its 16-pin SOIC footprint and I2C interface requirements. The embedded crystal simplifies design but limits frequency customization. Consider the 56-byte NVSRAM limit for data storage needs. Verify that the 1.8V to 5.5V supply range aligns with system power rails. Check if the 2µA standby current meets strict power budget constraints for battery-operated end products.

Part Context

The 1338C-18SRI belongs to the 1338 series of real-time clock ICs from Renesas. It is functionally similar to the 1338AC-18SRGI but differs in packaging and specific electrical characteristics. This model represents a legacy solution for timekeeping applications before being superseded by newer generations. It shares architectural similarities with other I2C-based RTCs but is distinct due to its embedded crystal feature.

Replacement Considerations

Analog Devices Inc./Maxim Integrated DS1338C-18# is listed as a direct substitute. Verify pinout compatibility and software register mapping differences between the Renesas and Analog Devices versions before implementation.

FAQ

Does the 1338C-18SRI include an external crystal?

No, the 1338C-18SRI features an embedded crystal oscillator, eliminating the need for an external quartz crystal.

What is the maximum standby current consumption?

The maximum current consumption is 2µA when operating at 3.3V.

Is the device suitable for industrial temperature environments?

Yes, the operating temperature range extends from -40°C to 85°C, making it suitable for industrial applications.