X1286V14
| Model | X1286V14 |
| Description | Intersil Real Time Clock/Calendar/CPU Supervisor with EEPROM X1286 |
| PDF file | Total 25 pages (File size: 362K) |
| Chip Manufacturer | INTERSIL |
X1286
devices have an IRQ- output which can be checked by
setting an alarm for each minute. Using the pulse
interrupt mode setting, the once-per-minute interrupt
functions as an indication of proper oscillation.
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 supercapacitor for applications where Vcc
may disappear intermittently for short periods of time.
Depending on the value of supercapacitor 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 Vcc to charge the superca-
pacitor, which is connected to the Vback pin. Do not
use the diode to charge a battery (especially lithium
batteries!).
Table 9. Battery Backup Operation
1. Example Application, Vcc = 5V, Vback = 3.0V
V
SS
Figure 16. Supercapactor charging circuit
2.7-5.5V
V
CC
V
back
Supercapacitor
Since the battery switchover occurs at Vcc=Vback-
0.1V (see Figure 16), the battery voltage must always
be lower than the Vcc voltage during normal operation
or the battery will be drained.
The summary of conditions for backup battery opera-
tion is given in Table 9:
Condition
a. Normal Operation
b. Vcc on with no battery
c. Backup Mode
Vcc
5.00
5.00
0-1.8
Vback
3.00
0
1.8-3.0
Vtrip
4.38
4.38
4.38
Iback
<<1µA
0
<2µA
Notes
Timekeeping only
2. Example Application, Vcc = 3.3V,Vback = 3.0V
Condition
a. Normal Operation
b. Vcc on with no battery
c. Backup Mode
d. UNWANTED - Vcc ON, Vback
powering
Vcc
3.30
3.30
0-1.8
2.65 - 3.30
Vback
3.00
0
1.8-3.0*
> Vcc
Vtrip
2.65
2.65
2.65
2.65
Iback
<<1µA
0
<2µA*
up to 3mA
Timekeeping only
Internal Vcc=Vback
*since Vback>2.65V is higher than Vtrip, the battery is powering the entire device
22
FN8101.0
March 29, 2005
Related PDFs
| Model | Description | Manufacturer | Operation |
|---|---|---|---|
 X1286V14I
|
Intersil Real Time Clock/Calendar/CPU Supervisor with EEPROM X1286 | INTERSIL | Preview |
|
X1286V14I-T1
|
1 TIMER(S), REAL TIME CLOCK, PDSO14, 4.40 MM, PLASTIC, TSSOP-14 | RENESAS | Preview |
|
X1286V14ZT1
|
1 TIMER(S), REAL TIME CLOCK, PDSO14, 4.40 MM, ROHS COMPLIANT, PLASTIC, TSSOP-14 | RENESAS | Preview |
