ISL12028IV27AZ

Real Time Clock Overview

The ISL12028IV27AZ is a low-power Real Time Clock (RTC) and calendar integrated circuit manufactured by Renesas Electronics. It features an I2C bus interface with a maximum data transfer rate of 400kHz. The device includes two non-volatile alarms, intelligent battery backup switching, and CPU supervisor functions such as Power-On Reset and Watchdog Timer. It integrates 512x8-bit EEPROM for data storage. The oscillator utilizes an external 32.768kHz crystal with on-chip compensation. Operating voltage ranges from 2.7V to 5.5V for VDD and 1.8V to 5.5V for VBAT. The component is housed in a 14-lead TSSOP package.

Real Time Clock Feature Summary

• Real-time clock/calendar tracking hours, minutes, seconds, date, month, year, and day of week with automatic leap year correction through 2099.
• Integrated 512x8-bit EEPROM with 16-byte page write mode, BlockLock protection, and >2,000,000 cycle endurance.
• Intelligent battery backup switching with power-fail detection and low battery supply current of 800nA typical at 1.8V.
• On-chip oscillator compensation with 64-position digitally controlled trim capacitors for frequency adjustment within ±30ppm.

Real Time Clock Applications

• Utility meters
• HVAC equipment
• Network routers, hubs, switches, and bridges
• Cellular infrastructure equipment
• POS equipment

Real Time Clock Procurement Notes

Verify the specific suffix 'AZ' against official Renesas documentation, as standard listings often use 'Z' or 'Z-T'. Confirm availability status, as many variants in this family are marked as obsolete or limited supply. Ensure the selected package matches the 14-lead TSSOP form factor required for the design.

Real Time Clock Selection Notes

Select the ISL12028 variant based on the required VRESET threshold; the '27' suffix indicates a 2.63V reset level. Choose the 'IV' prefix for TSSOP packaging. Consider the ISL12028A series if the application requires Standard Mode settings where VBAT exceeds VDD. Verify I2C compatibility and pull-up resistor requirements for the target system voltage.

Real Time Clock Part Context

This component belongs to the ISL12028 family of real-time clocks. It shares core functionality with the ISL12028A but differs in power control settings, utilizing Legacy Mode. The device is designed for applications requiring precise timekeeping with non-volatile memory and supervisory capabilities in a compact surface-mount package.

Real Time Clock Replacement Considerations

The datasheet explicitly states this product is obsolete with no recommended replacement. Contact Renesas Technical Support for potential alternatives. Cross-referencing with other RTCs may require significant schematic and firmware modifications due to unique register maps and EEPROM interfaces.