ISL12028IB27Z-T Intersil, ISL12028IB27Z-T Datasheet - Page 16

• Manufacturer Part Number: ISL12028IB27Z-T
• Description: IC RTC/CALENDAR EEPROM 14-SOIC
• Manufacturer: Intersil
• Type: Clock/Calendar/Supervisor/EEPROMr

Specifications of ISL12028IB27Z-T

• 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: 14-SOIC (3.9mm Width), 14-SOL
• 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
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ISL12028IB27Z-TTR

for up to a month. See “Application Section” on page 22 for
more information.
There are two options for setting the change-over conditions
from V
register controls this operation.
Option 1 - Standard Mode (Default for ISL12028A)
Option 2 - Legacy Mode (Default for ISL12028)
Note that applications that have V
ISL12028A (standard mode) for proper start-up. Note that
the I
backup, that function is controlled by the SBIB bit. That
operation is covered after the power control section.
OPTION 1 - STANDARD POWER CONTROL MODE
(DEFAULT FOR ISL12028A)
In the Standard mode, the supply will switch over to the
battery when V
lower. In this mode, accidental operation from the battery is
prevented since the battery backup input will only be used
when the V
To select Option 1, BSW bit in the Power Register must be
set to “BSW = 0”. Following is a description of power
switchover.
Standard Mode Power Switchover
• Normal Operating Mode (V
To transition from the V
following conditions must be met:
• Battery Backup Mode (V
The ISL12028 device will switch from the V
when one of the following conditions occurs:
TABLE 7. V
BSW BIT
(V
- Condition 1:
- Condition 2:
- Condition 1:
- Condition 2:
2
BAT
V
where V
V
where V
V
where V
V
where V
0
1
C may or may not be operational during battery
DD
DD
DD
DD
DD
)
< V
< V
> V
> V
to Battery back-up mode. The BSW bit in the PWR
DD
BAT
BATHYS
TRIP
BATHYS
TRIPHYS
V
BAT
TRIP
BAT
TRIP
BAT
DD
supply is shut off.
V
TRIP POINT WITH DIFFERENT BSW SETTING
- V
+ V
DD
≈ 2.2V
+ V
TRIP POINT
drops below V
(V)
2.2
BATHYS
< V
BATHYS
≈ 50mV
≈ 50mV
TRIPHYS
≈ 30mV
BAT
DD
to V
BAT
16
DD
) to Normal Mode (V
BAT
Standard Mode (ISL12028A)
) to Battery Backup Mode
POWER CONTROL SETTING
Legacy Mode (ISL12028)
TRIP
BAT
mode, both of the
or V
> V
BAT
DD
BAT
, whichever is
will require the
to V
ISL12028, ISL12028A
DD
DD
)
mode
There are two discrete situations that are possible when
using Standard Mode: V
These two power control situations are illustrated in
Figures 13 and 14.
OPTION 2 - LEGACY POWER CONTROL MODE
(DEFAULT FOR ISL12028)
The Legacy Mode follows conditions set in X1226 products.
In this mode, switching from V
comparing the voltages and the device operates from
whichever is the higher voltage. Care should be taken when
changing from Normal to Legacy Mode. If the V
higher than V
unless the battery is disconnected or the voltage decreases,
the device will no longer operate from V
situation on initial power-up, then I
be possible. For these applications, the ISL12028A should be
used.
To select Option 2, BSW bit in the Power Register must be
set to “BSW = 1”
• Normal Mode (V
To transition from the V
conditions must be met:
V
• Battery Backup Mode (V
The device will switch from the V
following condition occurs:
DD
FIGURE 13. BATTERY SWITCHOVER WHEN V
FIGURE 14. BATTERY SWITCHOVER WHEN V
V
V
V
V
V
TRIP
< V
V
TRIP
BAT
BAT
DD
DD
V
BAT
BAT
- V
- V
DD
V
BATHYS
TRIP
BATHYS
, then the device will enter battery backup and
DD
) to Battery Backup Mode (V
BATTERY BACKUP
DD
BAT
to V
BAT
BATTERY
< V
MODE
BACKUP
DD
MODE
) to Normal Mode (V
BAT
TRIP
BAT
to V
2
C communication may not
mode, the following
and V
BAT
to V
DD
is simply done by
DD
. If that is the
V
BAT
TRIP
V
mode when the
BAT
BAT
November 30, 2010
> V
BAT
BAT
+ V
+ V
TRIPHYS
BAT
TRIP
voltage is
< V
> V
DD
BATHYS
3.0V
2.2V
2.2V
1.8V
)
)
FN8233.9
TRIP
TRIP
.