Rev 2; 12/04
2
I C RTC with Trickle Charger
General Description
Features
♦ Enhanced Second Source for the ST M41T00
The DS1340 is a real-time clock (RTC)/calendar that is
pin compatible and functionally equivalent to the ST
M41T00, including the software clock calibration. The
device additionally provides trickle-charge capability
♦ Available in a Surface-Mount Package with an
Integrated Crystal (DS1340C)
2
♦ Fast (400kHz) I C Interface
on the V
pin, a lower timekeeping voltage, and
BACKUP
♦ Software Clock Calibration
an oscillator STOP flag. Block access of the register
map is identical to the ST device. Two additional regis-
ters, which are accessed individually, are required for
the trickle charger and flag. The clock/calendar pro-
vides seconds, minutes, hours, day, date, month, and
year information. A built-in power-sense circuit detects
power failures and automatically switches to the back-
up supply. The device is programmed serially through
♦ RTC Counts Seconds, Minutes, Hours, Day, Date,
Month, and Year
♦ Automatic Power-Fail Detect and Switch Circuitry
♦ Trickle-Charge Capability
♦ Low Timekeeping Voltage Down to 1.3V
♦ Three Operating Voltage Ranges (1.8V, 3V, and 3.3V)
♦ Oscillator Stop Flag
2
an I CTM bidirectional bus.
♦ Available in 8-Pin µSOP or SO Packages
♦ Underwriters Laboratory (UL) Recognized
Applications
Ordering Information
Portable Instruments
Point-of-Sale Equipment
Medical Equipment
Telecommunications
TOP
MARK
PART
TEMP RANGE PIN-PACKAGE
DS1340Z-18
DS1340Z-3
DS1340Z-33
-40°C to +85°C 8 SO (0.150in)
-40°C to +85°C 8 SO (0.150in)
-40°C to +85°C 8 SO (0.150in)
D1340-18
DS1340-3
D1340-33
1340
A1-18
1340
A1-3
Typical Operating Circuit
DS1340U-18
DS1340U-3
DS1340U-33
-40°C to +85°C 8 µSOP
-40°C to +85°C 8 µSOP
-40°C to +85°C 8 µSOP
V
CC
1340
A1-33
V
CC
CRYSTAL
1
RPU
RPU
V
CC
DS1340C-18
DS1340C-3
DS1340C-33
-40°C to +85°C 16 SO
-40°C to +85°C 16 SO
-40°C to +85°C 16 SO
1340C-18
1340C-3
2
8
X1
SCL
X2
V
CC
7
3
6
5
1340C-33
D1340-18
DS1340-3
D1340-33
FT/OUT
DS1340Z-18+ -40°C to +85°C 8 SO (0.150in)
DS1340Z-3+ -40°C to +85°C 8 SO (0.150in)
CPU
DS1340
SDA
V
BACKUP
DS1340Z-33+ -40°C to +85°C 8 SO (0.150in)
GND
4
1340
A1-18
RPU = t / C
DS1340U-18+ -40°C to +85°C 8 µSOP
R
B
1340
A1-3
DS1340U-3+
-40°C to +85°C 8 µSOP
1340
A1-33
DS1340U-33+ -40°C to +85°C 8 µSOP
DS1340C-18+ -40°C to +85°C 16 SO
1340C-18
1340C-3
1340C-33
2
2
I C is a trademark of Philips Corp. Purchase of I C compo-
nents from Maxim Integrated Products, Inc., or one of its subli-
censed Associated Companies, conveys a license under the
DS1340C-3+
-40°C to +85°C 16 SO
DS1340C-33+ -40°C to +85°C 16 SO
2
2
Philips I C Patent Rights to use these components in an I C
system, provided that the system conforms to the I C Standard
2
Note: A "+" in the part number and a "+" anywhere on the top
mark indicates a lead-free device.
Specification as defined by Philips.
Pin Configurations appear at end of data sheet.
______________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.