
1
Low Power RTC with Battery Backed SRAM, Integrated
±5ppm Temperature Compensation and Auto Daylight
Saving
ISL12022MA
The ISL12022MA 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. Backup battery current draw is less
than 1.6A over the temperature range. 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 VDD to VBAT power, and
also from VBAT to VDD power.
The ISL12022MA features enhanced immunity to ESD per the
IEC61000-4-2 standard, and also provides improved resistance
to system leakage related to environmental moisture.
Related Literature
See
TB484 “ISL12022MA Enhanced RTC Module”
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
1.6A Max Battery Current
I2C Bus
RoHS Compliant
Applications
Utility Meters
POS Equipment
Printers and Copiers
Digital Cameras
FIGURE 1. TYPICAL APPLICATION CIRCUIT
GND
NC
GND
NC
VBAT
VDD
GND IRQ/FOUT
NC
SCL
SDA
ISL12022MA
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
SCHOTTKY DIODE
BAT54
BATTERY
3.0V
3.3V
C2
0.1F
C1
0.1F
R1
10k
R2
10k
R3
10k
VDO
SCL
SDA
GND
MCU
INTERFACE
IRQ/FOUT
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
|Copyright Intersil Americas Inc. 2010- 2012. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. I2C Bus is a registered trademark
owned by NXP Semiconductors Netherlands, B.V. All other trademarks mentioned are the property of their respective owners.
September 5, 2012
FN7575.5