DS1340U Datasheet, PDF (1/16 Pages) Maxim Integrated Products – I2C RTC with Trickle Charger

DS1340
I²C RTC with Trickle Charger
General Description
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
on the V_BACKUP pin, a lower timekeeping voltage, and
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. Reads and writes are inhibited while the
clock continues to run. The device is programmed seri-
ally through an I²C bidirectional bus.
Portable Instruments
Point-of-Sale Equipment
Medical Equipment
Telecommunications
Applications
Typical Operating Circuit
V_CC
V_CC
CRYSTAL
V_{CC RPU}
R_PU
1
2
8
C1
X1 X2
6 _SCL
V_CC
7
FT/OUT
CPU
DS1340
5 _SDA
R_PU = t_R / C_B
3
V_BACKUP
GND
4
Features
♦ Enhanced Second Source for the ST M41T00
♦ Available in a Surface-Mount Package with an
Integrated Crystal (DS1340C)
♦ Fast (400kHz) I²C Interface
♦ Software Clock Calibration
♦ 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
♦ Available in 8-Pin µSOP or SO Packages
♦ Underwriters Laboratories (UL) Recognized
Ordering Information
PART
TEMP RANGE ^PIN-
TOP MARK^†
PACKAGE
DS1340Z-18+
-40°C to +85°C
8 SO
(0.150in)
D1340-18
DS1340Z-3+ -40°C to +85°C ^{8 SO}
(0.150in)
DS1340-3
DS1340Z-33+ -40°C to +85°C ^{8 SO}
(0.150in)
D134033
DS1340U-18+ -40°C to +85°C 8 μSOP
DS1340U-3+ -40°C to +85°C 8 μSOP
DS1340U-33+ -40°C to +85°C 8 μSOP
DS1340C-18# -40°C to +85°C 16 SO
DS1340C-3# -40°C to +85°C 16 SO
DS1340C-33# -40°C to +85°C 16 SO
1340 -18
1340 -3
1340 -33
DS1340C-18
DS1340C-3
DS1340C-33
+Denotes a lead(Pb)-free/RoHS-compliant package.
#Denotes a RoHS-compliant device that may include lead(Pb)
that is exempt under RoHS requirements. The lead finish is
JESD97 category e3, and is compatible with both lead-based
and lead-free soldering processes.
†A "+" anywhere on the top mark denotes a lead(Pb)-free device.
A "#" denotes a RoHS-compliant device.
Pin Configurations appear at end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim Direct at
1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
19-5578; Rev 8; 4/13