ISL12028AIB27Z-T

Real Time Clock Overview

The ISL12028AIB27Z-T is a low-power real-time clock/calendar with I2C bus interface and integrated 512x8-bit EEPROM. It tracks time in hours, minutes, and seconds with calendar registers accurate through 2099, including automatic leap year correction. The device features two non-volatile alarms, intelligent battery backup switching, and on-chip oscillator compensation with a 64-position digital trim capacitor. Operating voltage ranges from 2.7V to 5.5V for VDD and 1.8V to 5.5V for VBAT. Battery supply current is typically 800nA at 1.8V. It includes CPU supervisor functions such as Power-On Reset, Low Voltage Sense, and a Watchdog Timer. The component is housed in a 14-lead SOIC package.

Real Time Clock Feature Summary

• Integrated 512x8-bit (4k-bit) EEPROM with 16-byte page write mode and BlockLock protection
• Two non-volatile alarms settable to second, minute, hour, day of week, day, or month
• On-chip oscillator compensation with 64-position digitally controlled trim capacitor
• CPU Supervisor functions including Power-On Reset, Low Voltage Sense, and Watchdog Timer

Real Time Clock Applications

• Utility Meters
• HVAC Equipment
• Network Routers, Hubs, Switches, Bridges
• POS Equipment
• Computer Products

Real Time Clock Procurement Notes

Verify the specific suffix 'T' indicates tape and reel packaging per manufacturer tech briefs. Confirm the 'A' designation corresponds to Standard Mode power control settings, which are distinct from Legacy Mode variants. Ensure compatibility with systems where VBAT exceeds VDD, as this variant is specified for such configurations. Check for obsolescence status as Intersil products may have limited support.

Real Time Clock Selection Notes

Select this model when VBAT is expected to be greater than VDD, as it utilizes Standard Mode power control settings unlike the legacy ISL12028 variants. Ensure the application requires 512 bytes of non-volatile storage for configuration data. Verify that the 14-lead SOIC package fits the PCB layout constraints. Confirm the need for on-chip oscillator compensation to minimize external component count.

Real Time Clock Part Context

This part belongs to the ISL12028 family of real-time clocks manufactured by Renesas Electronics (formerly Intersil). The 'A' suffix denotes the Standard Mode power control setting, differentiating it from the legacy mode devices. The 'IB27' code specifies the 2.63V reset threshold and -40°C to +85°C operating temperature range. The 'Z' indicates Pb-free/RoHS compliance, and '-T' denotes tape and reel packaging.

Real Time Clock Replacement Considerations

The datasheet explicitly states this product is obsolete with no recommended replacement. Contact Technical Support for alternatives.