isl12022m Intersil Corporation, isl12022m Datasheet - Page 8

• Manufacturer Part Number: isl12022m
• Description: Real Time Clock With Embedded Crystal, ??5ppm Accuracy
• Manufacturer: Intersil Corporation

Typical Performance Curves
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
FIGURE 8. I
100
110
5.5
5.0
4.5
4.0
3.5
3.0
2.5
90
80
70
60
50
40
FIGURE 10. I
-40
-40
DD
-20
-20
vs TEMPERATURE, 3 DIFFERENT F
V
DD
DD
WITH TSE = 1 vs TEMPERATURE
= 2.7V
0
0
TEMPERATURE (°C)
TEMPERATURE (°C)
F
OUT
V
BAT
8
20
= 32kHz
20
= 5.5V
F
OUT
= 1Hz
40
40
F
OUT
Temperature is +25°C unless otherwise specified. (Continued)
60
V
60
= 64Hz
DD
= 3.3V
OUT
80
80
ISL12022M
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/F
a periodic interrupt every minute, every hour, every day, etc.
The device also offers a backup power input pin. This V
pin allows the device to be backed up by battery or
supercapacitor with automatic switchover from V
The ISL12022M device is specified for V
and the clock/calendar portion of the device remains fully
operational in battery backup mode down to 1.8V (Standby
Mode). The V
preselected levels. The first report is registered when the
V
is set for 75%. Battery levels are stored in V
The ISL12022M offers a “Brownout” alarm once the V
below a pre-selected trip level. This allows system Micro to
save vital information to memory before complete power loss.
There are six V
the Brownout alarm.
BAT
FIGURE 9. I
FIGURE 11. OSCILLATOR CHANGE vs TEMPERATURE AT
level falls below 85% of nominal level; the second level
100
OUT
110
-20
-40
-60
-80
80
60
40
20
90
80
70
60
50
40
30
20
0
-40
-40
pin. There is a repeat mode for the alarm allowing
BAT
DIFFERENT AGING SETTINGS (IATR) (BETA SET
FOR 1ppm STEPS)
BAT
DD
V
-20
DD
-20
WITH TSE = 1, BTSE = 1 vs TEMPERATURE
level is monitored and reported against
levels that could be selected for initiation of
= 3.0V
-61.5ppm
32ppm
V
0ppm
BAT
0
0
TEMPERATURE (°C)
TEMPERATURE (°C)
= 5.5V
V
DD
= 1.8V
20
20
62.5ppm
-31ppm
40
40
DD
BATM
= 2.7V to 5.5V
60
December 18, 2008
60
DD
registers.
to V
DD
FN6668.4
80
80
BAT
BAT
falls
.