ISL12027IV27AZ Intersil, ISL12027IV27AZ Datasheet - Page 16

• Manufacturer Part Number: ISL12027IV27AZ
• Description: IC RTC/CALENDAR EEPROM 8-TSSOP
• Manufacturer: Intersil
• Type: Clock/Calendar/Supervisor/EEPROMr

Specifications of ISL12027IV27AZ

• 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-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Standard Mode Power Switchover
• Normal Operating Mode (V
To transition from the V
following conditions must be met:
• Condition 1:
• Condition 2:
• Battery Backup Mode (V
The ISL12027 device will switch from the V
when one of the following conditions occurs:
• Condition 1:
• Condition 2:
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
(ISL12027 DEFAULT)
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
(V
V
where V
V
where V
V
where V
V
where V
FIGURE 13. BATTERY SWITCHOVER WHEN V
FIGURE 14. BATTERY SWITCHOVER WHEN V
V
DD
DD
DD
DD
V
V
V
BAT
V
TRIP
V
TRIP
BAT
BAT
DD
DD
V
< V
< V
> V
> V
BAT
)
BATHYS
TRIP
BATHYS
TRIPHYS
BAT
TRIP
BAT
TRIP
- V
V
BATHYS
TRIP
- V
+ V
≈ 2.2V
+ V
BATHYS
BATHYS
≈ 50mV
≈ 50mV
TRIPHYS
≈ 30mV
BATTERY BACKUP
DD
BAT
BATTERY BACKUP
to V
BAT
16
< V
MODE
DD
DD
MODE
) to Normal Mode (V
BAT
TRIP
) to Battery Backup Mode
to V
mode, both of the
and V
BAT
is simply done by
V
BAT
BAT
TRIP
V
BAT
> V
BAT
BAT
to V
+ V
+ V
ISL12027, ISL12027A
TRIPHYS
TRIP
< V
> V
DD
DD
BATHYS
3.0V
2.2V
2.2V
1.8V
)
TRIP
TRIP
mode
.
changing from Normal to Legacy Mode. If the V
higher than V
and unless the battery is disconnected or the voltage
decreases, the device will no longer operate from V
is the situation on initial power-up, then I
may not be possible. For these applications, the ISL12027A
should be used.
To select the 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:
V
The Legacy Mode power control conditions are illustrated in
Figure 15.
Power On Reset
Application of power to the ISL12027 activates a Power On
Reset Circuit that pulls the RESET pin active. This signal
provides several benefits.
• It prevents the system microprocessor from starting to
• It prevents the processor from operating prior to
• It allows time for an FPGA to download its configuration
• It prevents communication to the EEPROM, greatly
When V
typically 250ms the circuit releases RESET, allowing the
system to begin operation. Recommended slew rate is
between 0.2V/ms and 50V/ms.
NOTE: If the V
minimum of 1.8V and the V
to V
I
power will need to be cycled to 0V together to allow normal
operation again.
2
DD
DD
C communications will not operate. The V
operate with insufficient voltage.
stabilization of the oscillator.
prior to initialization of the circuit.
reducing the likelihood of data corruption on power-up.
V
FIGURE 15. BATTERY SWITCHOVER IN LEGACY MODE
BAT
DD
< V
> V
voltage, then the RESET output may stay low and the
DD
BAT
BAT
exceeds the device V
+V
- V
DD
BAT
BATHYS
BATHYS
, then the device will enter battery back up
OFF
DD
voltage drops below the data sheet
) to Battery Backup Mode (V
DD
V
DD
to V
BAT
DD
) to Normal Mode (V
power cycles to 0V then back
BAT
BAT
RESET
mode, the following
VOLTAGE
to V
2
threshold value for
C communication
DD
BAT
mode when the
BAT
and V
August 12, 2010
ON
BAT
DD
voltage is
DD
FN8232.8
. If that
DD
)
)
IN