Rainbow Electronics DS1340 - Manual

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. The device is programmed serially through
a 2-wire bidirectional bus.
Applications
Portable Instruments
Point-of-Sale Equipment
Medical Equipment
Telecommunications
Features
♦ Enhanced Second Source for the ST M41T00
♦ Fast (400kHz) 2-Wire 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
DS1340
2-Wire RTC with Trickle Charger
______________________________________________ Maxim Integrated Products 1
1
2
3
4
8
7
6
5
V CC
FT/OUT
SCL
SDA
V
BACKUP
GND
X2
X1
TOP VIEW
DS1340
SO, µ SOP
Pin Configuration
Ordering Information
4
CPU
V CC
V CC
V CC
5
6
8 1 2
SDA
SCL
GND
X2 X1
V CC
RPU RPU
CRYSTAL
FT/OUT
V BACKUP
3
7
RPU = t R / C B
DS1340
Typical Operating Circuit
Rev 0; 6/03
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.
PART TEMP RANGE
PIN-
PACKAGE TOP
MARK
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) D1340-33
DS1340U-18 -40°C to +85°C 8 µSOP
1340
A1-18
DS1340U-3 -40°C to +85°C 8 µSOP
1340
A1-3
DS1340U-33 -40°C to +85°C 8 µSOP
1340
A1-33