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 I
2
C bidirectional bus.
Features
♦
Enhanced Second Source for the ST M41T00
♦
Available in a Surface-Mount Package with an
Integrated Crystal (DS1340C)
♦
Fast (400kHz) I
2
C 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
Applications
Portable Instruments
Point-of-Sale Equipment
Medical Equipment
Telecommunications
DS1340Z-18+
DS1340Z-3+
PART
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
8 SO
(0.150in)
8 SO
(0.150in)
8 SO
(0.150in)
TOP MARK
†
D1340-18
DS1340-3
D134033
1340 -18
1340 -3
1340 -33
DS1340C-18
DS1340C-3
DS1340C-33
Typical Operating Circuit
DS1340Z-33+
V
CC
CRYSTAL
V
CC
R
PU
R
PU
1
X1
6 SCL
CPU
5 SDA
R
PU
= t
R
/ C
B
GND
4
2
X2
8
V
CC
FT/OUT
7
C1
V
CC
DS1340U-18+
DS1340U-3+
DS1340U-33+
DS1340C-18#
DS1340C-3#
DS1340C-33#
-40°C to +85°C 8 μSOP
-40°C to +85°C 8 μSOP
-40°C to +85°C 8 μSOP
-40°C to +85°C 16 SO
-40°C to +85°C 16 SO
-40°C to +85°C 16 SO
DS1340
V
BACKUP
3
+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
DS1340
I
2
C RTC with Trickle Charger
ABSOLUTE MAXIMUM RATINGS
Voltage Range on V
CC
or V
BACKUP
Pins
Relative to Ground.............................................-0.3V to +6.0V
Voltage Range on SDA, SCL, and FT/OUT
Relative to Ground..................................-0.3V to (V
CC
+ 0.3V)
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-55°C to +125°C
Lead Temperature (soldering, 10s) .................................+260°C
Soldering Temperature (reflow) .......................................+260°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED DC OPERATING CONDITIONS
(V
CC
= V
CC MIN
to V
CC MAX
, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
CC
= 3.3V, T
A
= +25°C, unless
otherwise noted.) (Note 1)
PARAMETER
Supply Voltage (Note 2)
Input Logic 1 (SDA, SCL)
Input Logic 0 (SDA, SCL)
Supply Voltage, Pullup
(FT/OUT, SDA, SCL), V
CC
= 0V
Backup Supply Voltage (Note 2)
SYMBOL
DS1340-18
V
CC
V
IH
V
IL
V
PU
DS1340-3
DS1340-33
(Note 2)
(Note 2)
(Note 2)
DS1340-18
V
BACKUP
R1
Trickle-Charge Current-Limiting
Resistors
R2
R3
Power-Fail Voltage (Note 2)
Input Leakage (SCL, CLK)
I/O Leakage (SDA, FT/OUT)
SDA Logic 0 Output
V
PF
I
LI
I
LO
I
OLSDA
V
CC
> 2V; V
OL
= 0.4V
1.7V < V
CC
< 2V; V
OL
= 0.2 x V
CC
V
CC
> 2V; V
OL
= 0.4V
1.7V < V
CC
< 2V; V
OL
= 0.2 x V
CC
1.3V < V
CC
< 1.7V; V
OL
= 0.2x V
CC
DS1340-18; V
CC
= 1.89V
Active Supply Current (Note 7)
I
CCA
DS1340-3; V
CC
= 3.3V
DS1340-33; V
CC
= 5.5V
DS1340-18; V
CC
= 1.89V
Standby Current (Note 8)
V
BACKUP
Leakage Current
I
CCS
DS1340-3; V
CC
= 3.3V
DS1340-33; V
CC
= 5.5V
I
BACKUPLKG
V
BACKUP
= 3.7V
72
108
192
60
81
100
DS1340-3
DS1340-33
(Notes 3, 4)
(Note 5)
(Note 6)
DS1340-18
DS1340-3
DS1340-33
1.51
2.45
2.70
-1
-1
1.3
1.3
1.3
250
2000
4000
1.6
2.6
2.88
1.71
2.7
2.97
+1
+1
3.0
3.0
3.0
3.0
250
150
200
300
100
125
150
100
nA
μA
μA
μA
μA
mA
mA
μA
V
CONDITIONS
MIN
1.71
2.7
2.97
0.7 x V
CC
-0.3
TYP
1.8
3.0
3.3
MAX
5.5
5.5
5.5
V
CC
+ 0.3
+0.3 x V
CC
5.5
3.7
3.7
5.5
V
V
V
V
V
UNITS
FT/OUT Logic 0 Output
I
OLSQW
2
Maxim Integrated
DS1340
I
2
C RTC with Trickle Charger
DC ELECTRICAL CHARACTERISTICS
(V
CC
= 0V, V
BACKUP
= 3.7V, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 1)
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