ISL12022M_10 Datasheet, PDF (1/31 Pages) Intersil Corporation – Low Power RTC with Battery Backed SRAM,Integrated ±5ppm Temperature Compensation and Auto Daylight Saving

Low Power RTC with Battery Backed SRAM,
Integrated ±5ppm Temperature Compensation and
Auto Daylight Saving
ISL12022M
The ISL12022M device is a low power real time clock
(RTC) with an embedded temperature sensor and
crystal. Device functions include oscillator compensation,
clock/calendar, power fail and low battery monitors,
brownout indicator, one-time, periodic or polled alarms,
intelligent battery backup switching, Battery Reseal™
function and 128 bytes of battery-backed user SRAM.
The device is offered in a 20 Ld SOIC module that
contains the RTC and an embedded 32.768kHz quartz
crystal. The calibrated oscillator provides less than
±5ppm drift over the full -40°C to +85°C temperature
range.
The RTC tracks time with separate registers for hours,
minutes, and seconds. The calendar registers track date,
month, year and day of the week and are accurate
through 2099, with automatic leap year correction.
Daylight Savings time adjustment is done automatically,
using parameters entered by the user. Power fail and
battery monitors offer user-selectable trip levels. The
time stamp function records the time and date of
switchover from V_DD to V_BAT power, and also from V_BAT
to V_DD power.
Related Literature*(see page 30)
• See AN1549 “Addressing Power Issues in Real Time
Clock Applications”
Features
• Embedded 32.768kHz Quartz Crystal in the Package
• 20 Ld SOIC Package (for DFN version, refer to the
ISL12020M)
• Calendar
• On-chip Oscillator Temperature Compensation
• 10-bit Digital Temperature Sensor Output
• 15 Selectable Frequency Outputs
• Interrupt for Alarm or 15 Selectable Frequency
Outputs
• Automatic Backup to Battery or Supercapacitor
• VDD and Battery Status Monitors
• Battery Reseal™ Function to Extend Battery Shelf
Life
• Power Status Brownout Monitor
• Time Stamp for Battery Switchover
• 128 Bytes Battery-Backed User SRAM
• I²C-Bus™
• RoHS Compliant
Applications*(see page 30)
• Utility Meters
• POS Equipment
• Printers and Copiers
• Digital Cameras
Typical Application Circuit
SCHOTTKY DIODE
BAT54
BATTERY
3.0V
C2
0.1µF
1 _NC
NC ²⁰
2 _NC
NC ¹⁹
3 _NC
NC ¹⁸
4 _NC
NC ¹⁷
5 _NC
NC ¹⁶
6 _GND
GND ¹⁵
7 _{VBAT VDD} 14
8 _{GND IRQ/FOUT} 13
9 _NC
SCL ¹²
10 _NC
SDA ¹¹
ISL12022M
3.3V
C1
0.1µF R1 R2 R3
10k 10k 10k
VDD
SCL MCU
INTERFACE
SDA
GND
IRQ/FOUT
Performance Curve
5
OSCILLATOR ERROR vs TEMPERATURE
4
3
2
1
0
V_BAT = 5.5V
-1
V_DD = 2.7V
-2
-3
V_DD = 3.3V
-4
-5
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
June 4, 2010
FN6668.7
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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