ISL12022M View Datasheet(PDF) - Intersil
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ISL12022M Datasheet PDF : 27 Pages
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ISL12022M
Typical Performance Curves Temperature is +25°C unless otherwise specified. (Continued)
5.5
5.0
FOUT = 32kHz
4.5
4.0
3.5
FOUT = 64Hz
3.0
FOUT = 1Hz
2.5
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
FIGURE 8. IDD vs TEMPERATURE, 3 DIFFERENT FOUT
110
100
90
VBAT = 5.5V
80
70
60
50
VDD = 3.0V
40
30
VDD = 1.8V
20
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
FIGURE 9. IBAT WITH TSE = 1, BTSE = 1 vs TEMPERATURE
110
100
VBAT = 5.5V
90
80
VDD = 3.3V
70
60
VDD = 2.7V
50
40
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
FIGURE 10. IDD WITH TSE = 1 vs TEMPERATURE
General Description
The ISL12022M device is a low power real time clock (RTC)
with embedded temperature sensor and crystal. It contains
crystal frequency compensation circuitry over the operating
temperature range good to ±5ppm accuracy. It also contains a
clock/calendar with Daylight Savings Time (DST) adjustment,
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 internal 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 ISL12022M can be programmed for
automatic Daylight Saving Time (DST) adjustment by
entering local DST information.
The ISL12022M’s alarm can be set to any clock/calendar
value for a match. For example, every minute, every
8
80
60
32ppm
40
62.5ppm
20
0ppm
0
-20
-40
-61.5ppm
-31ppm
-60
-80
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
FIGURE 11. OSCILLATOR CHANGE vs TEMPERATURE AT
DIFFERENT AGING SETTINGS (IATR) (BETA SET
FOR 1ppm STEPS)
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 supercapacitor
with automatic switchover from VDD to VBAT. The ISL12022M
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 ISL12022M 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.
FN6668.5
July 10, 2009
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