ISL12022IBZ-T7A

1. Description

The ISL12022IBZ-T7A device is a low power real time clock (RTCs) with embedded temperature sensors. It contains crystal frequency compensation circuitry over the operating temperature range, clock/calendar, power fail and low battery monitors, brownout indicator, 1 periodic or polled alarm, intelligent battery-backup switching and 128 Bytes of battery-backed user SRAM.

The oscillator uses an external, low cost 32.768kHz crystal. The real time clock tracks time with separate registers for hours, minutes and seconds. The device has calendar registers for date, month, year and day of the week. The calendar is accurate through 2099, with automatic leap year correction. In addition, the ISL12022IBZ-T7A can be programmed for automatic Daylight Savings Time (DST) adjustment by entering local DST information.

The ISL12022IBZ-T7A’s alarm can be set to any clock/calendar value for a match, for example, every minute, every Tuesday or at 5:23 AM on March 21. The alarm status is available by checking the Status Register, or the device can be configured to provide a hardware interrupt via the IRQ/FOUT pin. There is a repeat mode for the alarm allowing a periodic interrupt every minute, every hour, every day, etc.

The device also offers a backup power input pin. This VBAT pin allows the device to be backed up by battery or super capacitor with automatic switchover from VDD to VBAT. The ISL12022IBZ-T7A device is specified for VDD = 2.7V to 5.5V and the clock/calendar portion of the device remains fully operational in battery-backup mode down to 1.8V (Standby Mode). The VBAT level is monitored and reported against preselected levels. The first report is registered when the VBAT level falls below 85% of nominal level, the second level is set for 75%. Battery levels are stored in PWR_VBAT registers.

The ISL12022IBZ-T7A offers a “Brownout” alarm once the VDD falls below a pre-selected trip level. This allows system Micro to save vital information to memory before complete power loss. There are six VDD levels that could be selected for initiation of the Brownout alarm. 

2. Features

    1. Real Time Clock/Calendar

          - Tracks Time in Hours, Minutes and Seconds

          - Day of the Week, Day, Month and Year

    2. On-chip Oscillator Compensation Over the Operating Temperature Range

          - ±5ppm Over -40°C to +85°C

    3. 10-bit Digital Temperature Sensor Output

          - ±2°C Accuracy

    4. Customer Programmable Day Light Saving Time

    5. 15 Selectable Frequency Outputs

    6. 1 Alarm

          - Settable to the Second, Minute, Hour, Day of the Week, Day, or Month

          - Single Event or Pulse Interrupt Mode

    7. Battery Reseal™ Function to Extend Battery Shelf Life

    8. Automatic Backup to Battery or Super Capacitor

          - Operation to VBAT = 1.8V

          - 1.0µA Battery Supply Current

    9. Battery Status Monitor

          - 2 User Programmable Levels

          - Seven Selectable Voltages for Each Level

  10. Power Status Brownout Monitor

          - Six Selectable Trip Levels, from 2.295V to 4.675V

  11. Oscillator Failure Detection

  12. Time Stamp for First VDD to VBAT, and Last VBAT to VDD

  13. 128 Bytes Battery-Backed User SRAM

  14. I2C Bus™

          - 400kHz Clock Frequency

  15. 1µA Typical Battery Current

  16. Pb-Free (RoHS Compliant)

3. Pin Configuration

4. Block Diagram