ISL1221

Low Power RTC with Battery Backed SRAM and Event Detection

OVERVIEW

The ISL1221 device is a low power real time clock with Event Detect and Time Stamp function, timing and crystal compensation, clock/calendar, power fail indicator, periodic or polled alarm, intelligent battery backup switching with separate FOUT output and 2 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.

KEY FEATURES

  • Real Time Clock/Calendar
  • Tracks Time in Hours, Minutes, and Seconds
  • Day of the Week, Day, Month, and Year
  • Security and Event Functions
  • Tamper detection with Time Stamp in Normal and Battery Backed modes
  • Event Detection During Battery Backed or Normal Modes
  • Selectable Event Input Sampling Rates Allows Low Power Operation
  • Selectable Glitch Filter on Event Input Monitor
  • Separate FOUT pin with 15 Selectable Frequencies
  • Single Alarm
  • Settable to the Second, Minute, Hour, Day of the Week, Day, or Month
  • Single Event or Pulse Interrupt Mode
  • Automatic Backup to Battery or Super Cap
  • Power Failure Detection
  • On-Chip Oscillator Compensation
  • 2 Bytes Battery-Backed User SRAM
  • I2C Interface
  • 400kHz Data Transfer Rate
  • 400nA Battery Supply Current
  • Small Package
  • 10 Ld MSOP
  • Pb-Free (RoHS Compliant)

BLOCK DIAGRAM

 Block Diagram

PARAMETRICS

Parameters
ISL1221
Basic Information
Production Status
Mass Production
Supply Voltage Vcc (Min) (V)
2.7
Supply Voltage Vcc (Max) (V)
5.5
VBAT (min)
1.8 V
VBAT (max)
5.5 V
IBAT (nA)
400
Alarms
1
Crystal Frequency Trimming
Yes
Selectable Frequency Output
15
CPU Supervisory Function POR
No
CPU Supervisory Function Watchdog Timer
No
Battery Seal
Yes
Battery Backup
Yes
IRQ_Bar
IRQ_bar/EVDET_bar
FOUT
FOUT
RESET_bar
No
Oscillator Compensation (ppm)
-94 to +140
SRAM
2 Bytes
Other Functions
Event Detect, Time Stamp
Memory Type
RAM
Bus/Output Interface
I2C
Time Keeping Current
1.2 µA
IRQ Pin
Yes
Freq. Out Pin
Yes
Timer
No
Tamper Detect
Yes
Reset
No
Qualification Level
Standard
Battery Voltage Range (V)
1.8 to 5.5
Supply Voltage Vcc Range (V)
2.7 to 5.5
Can Sample
YES
Temperature Range
-40 to +85

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