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bq4802Y
bq4802LY
SLUS464C 鈥?AUGUST 2000 鈥?REVISED JUNE 2002
PARALLEL REAL-TIME CLOCK WITH CPU SUPERVISOR AND
EXTERNAL SRAM NONVOLATILE MEMORY BACKUP
FEATURES
D
Real-Time Clock Counts Seconds Through
Centuries in BCD Format
鈥?bq4802Y: 5-V Operation
鈥?bq4802LY: 3.3-V Operation
On-Chip Battery-Backup Switchover Circuit
With Nonvolatile Control for External SRAM
Less Than 500 nA of Clock Operation Current
in Backup Mode
Microprocessor Reset With Push-Button
Override
Independent Watchdog Timer With
Programmable Time-Out Period
Power-Fail Interrupt Warning
Programmable Clock Alarm Interrupt Active
in Battery-Backup Mode
Programmable Periodic Interrupt
Battery-Low Warning
28-pin SOIC, TSSOP, and SNAPHAT Package
Options
5 k鈩?/div>
APPLICATIONS
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Telecommunications Base Stations
Servers
Handheld Data Collection Equipment
Medical Equipment
Handheld Instrumentation
Test Equipment
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DESCRIPTION
The bq4802Y/bq4802LY real-time clock is a low-power
microprocessor peripheral that integrates a time-of-
day clock, a century-based calendar, and a CPU super-
visor, with package options including a 28-pin SOIC,
TSSOP, or SNAPHAT that requires the bq48SH-28x6
to complete the two-piece module. The bq4802Y/
bq4802LY is ideal for fax machines, copiers, industrial
control systems, point-of-sale terminals, data loggers,
and computers.
TYPICAL APPLICATION
VCC
bq4802
RST
TO
碌P
WDO
ADDRESS BUS
DATA BUS
FROM
ADDRESS
DECODE
LOGIC
A0鈥揂3
DQ0鈥揇Q7
CS
INT
CMOS SRAM
62256L
ADDRESS BUS
A0鈥揂3
DQ0鈥揇Q7
VCC
CE
OE WR
CEIN
DATA BUS
FROM
碌P
I/O LINE
VOUT
WDI
CEOUT
OE
WE
X1
BC
3V
LITHIUM
CELL
X2
VSS
32.768 kHz
CRYSTAL
READ/
WRITE
CONTROL
FROM
碌P
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
Copyright
錚?/div>
2002, Texas Instruments Incorporated
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