ISL12025IBZ Intersil, ISL12025IBZ Datasheet - Page 23

• Manufacturer Part Number: ISL12025IBZ
• Description: IC RTC/CALENDAR EEPROM 8-SOIC
• Manufacturer: Intersil
• Type: Clock/Calendar/Supervisor/EEPROMr

Specifications of ISL12025IBZ

• Memory Size: 4K (512 x 8)
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Bus Type: Serial (I2C)
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• Operating Temperature Classification: Industrial
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Pin Count: 8
• Mounting: Surface Mount
• Clock Format: HH
• Clock Ic Type: RTC
• Interface Type: I2C, Serial
• Memory Configuration: 512 X 8
• Supply Voltage Range: 2.7V To 5.5V
• Digital Ic Case Style: SOIC
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Backup Battery Operation
Many types of batteries can be used with the Intersil RTC
products. 3.0V or 3.6V Lithium batteries are appropriate, and
sizes are available that can power a Intersil RTC device for
up to 10 years. Another option is to use a Super Cap for
applications where V
short periods of time. Depending on the value of Super Cap
used, backup time can last from a few days to two weeks
(with >1F). A simple silicon or Schottky barrier diode can be
used in series with V
is connected to the V
very low leakages, <1µA desirable. Do not use the diode to
charge a battery (especially lithium batteries!)
There are two possible modes for battery backup operation;
Standard and Legacy Mode. In Standard Mode, there are no
operational concerns when switching over to battery backup
since all other devices functions are disabled. Battery drain
is minimal in Standard Mode and return to Normal V
powered operations predictable. In Legacy modes, the V
pin can power the chip if the voltage is above V
V
communicate with the device under battery backup, but the
supply current drain is much higher than the Standard Mode
and backup time is reduced. During initial power-up, the
default mode is the Legacy Mode.
I
LVR Operation
Operation in Battery Backup Mode and LVR is affected by
the BSW and SBIB bits as described previously. These bits
allow flexible operation of the serial bus and EEPROM in
Battery Backup Mode, but certain operational details need to
be clear before utilizing the different modes. The most
significant detail is that once V
I
is programmed for I
2
2
TRIP
C communications cease regardless of whether the device
C Communications During Battery Backup and
(X1227
MODE
Mode)
A
B
. This makes it possible to generate alarms and
TABLE 9. I
SBIB BIT
0
0
2
2
DD
BAT
C operation in Battery Backup Mode.
DD
C, LV RESET, AND BATTERY BACKUP OPERATION SUMMARY (Shaded Row is same as X1227 operation)
BSW
to charge the supercapacitor, which
may disappear intermittently for
BIT
pin. Try to use Schottky diodes with
0
1
23
DD
V
Standard Mode,
SWITCHOVER
Legacy Mode,
TRIP
goes below V
V
VOLTAGE
DD
VBAT
= 2.2V typ
< V
BAT
DD
RESET
V
and
I
2
BAT
DD
C ACTIVE IN
YES, only if
BACKUP?
BATTERY
, then
> V
BAT
NO
ISL12025
RESET
EE PROM WRITE/READ
IN BATTERY BACKUP?
Table 9 describes four different modes possible with using
the BSW and SBIB bits and how they are affect LVR and
battery backup operation.
• Mode A - In this mode selection bits indicate a low V
• Mode B - In this mode the selection bits indicate
• Mode C - In this mode the selection bits indicate a low
• Mode D - In this mode the selection bits indicate
.
2.7V TO 5.5V
switchover combined with I
Mode. In actuality the V
switching to battery backup, which will disable I
ANYTIME the device goes into Battery Backup Mode.
Regardless of the battery voltage, the I
to the V
switchover to battery backup at V
communications in battery backup. In order to
communicate in Battery Backup Mode, the V
voltage must be less than the V
must be greater than V
bus pins must go to V
the same as the normal operating mode of the X1227
device
V
battery backup. Operation is actually identical to Mode A
with I
communications (see Figure 28).
switchover to battery backup at V
communications in battery backup. This mode is unique in
that there is I
than V
the safest for guaranteeing I
when there is a Valid V
FIGURE 28. SUPER CAPACITOR CHARGING CIRCUIT
DD
YES
NO
switchover combined with no communications in
2
C communications down to V
RESET
RESET
2
or V
C communication as long as V
voltage (see Figure 29).
BAT
V
Operation of I
V
communications. Battery switchover at
V
Operation of I
Mode, but only for
V
Bus must have pull-ups to V
DD
DD
TRIP
BAT
BAT
, whichever is greater. This mode is
V
DD
RESET
= V
DD
SS
.
> V
V
to communicate. This mode is
(see Figure 29).
RESET
2
will go below V
BAT
DD
C operation in Battery Backup
2
C communications only
. Also, pull-ups on the I
> V
2
2
BAT
C bus down to
C bus into Battery Backup
, then below that no
DD
DD
RESET
NOTES
DD
voltage AND V
<V
< V
2
= V
BAT
.
C will work down
BAT
SUPER CAP
RESET
RESET
, and I
, and no I
BAT
RESET
DD
August 13, 2008
2
.
C
is higher
2
, then no
before
C
DD
FN6371.3
2
DD
2
C
C