DATASHEET
REAL-TIME CLOCK WITH SERIAL I
2
C INTERFACE
General Description
The IDT1339 serial real-time clock (RTC) is a low-power
clock/date device with two programmable time-of-day
alarms and a programmable square-wave output. Address
and data are transferred serially through an I
2
C bus. The
clock/date provides seconds, minutes, hours, day, date,
month, and year information. The date at the end of the
month is automatically adjusted for months with fewer than
31 days, including corrections for leap year. The clock
operates in either the 24-hour or 12-hour format with
AM/PM indicator. The IDT1339 has a built-in power-sense
circuit that detects power failures and automatically
switches to the backup supply, maintaining time, date, and
alarm operation.
IDT1339
Features
•
Real-Time Clock (RTC) counts seconds, minutes, hours,
day, date, month, and year with leap-year compensation
valid up to 2100
•
Packaged in 8-pin MSOP, 8-pin SOIC, or 16-pin SOIC
(surface-mount package with an integrated crystal)
Applications
•
Handhelds (GPS, POS terminals)
•
Consumer Electronics (Set-Top Box, Digital Recording,
Network Applications)
•
•
•
•
•
•
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Fast mode I
2
C Serial interface
Two time-of-day alarms
Programmable square-wave output
Oscillator stop flag
Automatic power-fail detect and switch circuitry
Trickle-charge capability
Industrial temperature range (-40 to +85°
C)
•
•
•
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Office (Fax/Printers, Copiers)
Medical (Glucometer, Medicine Dispensers)
Telecomm (Routers, Switches, Servers)
Other (Thermostats, Vending Machines, Modems, Utility
Meters)
Block Diagram
Crystal inside package
for 16-pin SOIC ONLY
1 Hz/4.096 kHz/
8.192 kHz/32.768 kHz
X1
32.768 kHz
Oscillator and
Divider
MUX/
Buffer
SQW/INT
X2
GND
VCC
Trickle
Charger
Power
Control
Control
Logic
Clock,
Calendar
Counter
V
BACKUP
SDA
I
2
C
Interface
Trickle
Charger
Byte
SCL
1 Byte
Control
7 Bytes
Buffer
7 Bytes
Alarm
1 Byte
Status
IDT®
REAL-TIME CLOCK WITH SERIAL I
2
C INTERFACE
1
IDT1339
REV K 032910
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
