The DS1318 parallel-interface elapsed time counter
(ETC) is a 44-bit counter that maintains the amount of
time that the device operates from main and/or backup
power or during an external event. The internal
frequency of the counter clock is 4.096kHz, which pro-
vides a 244µs resolution and a maximum count of over
136 years. A built-in power-sense circuit detects power
failures, automatically switches to the backup supply,
and controls the timer. If an external event timer is
desired, the control input EXT can control the counter
operation. An open-drain output provides an interrupt,
and a square-wave output provides a programmable
square wave. The DS1318 is accessed through a byte-
wide parallel interface, and operates over the industrial
temperature range.
♦
Byte-Wide Parallel Interface
♦
44-Bit Binary Counter Provides Timer with 244µs
Resolution
♦
Automatic Power-Fail Detect and Switch Circuitry
Selects Power Source from the Primary Power
and the Battery, and Write Protects the Internal
Registers
♦
Internal Power-Fail Circuit Allows Timer to
Provide Primary or Battery Operation Times
♦
Timer can Alternately Provide an Event Timer of
Either an Active-High or Active-Low Pulse
♦
Interrupt Output Generated Periodically or When
the Upper 32 Bits of the Counter Match an Alarm
Register
♦
Square-Wave Output with 16 Selectable
Frequencies from 32.768kHz to 0.5Hz
Features
DS1318
Applications
Power Meters
Industrial Controls
Servers
♦
+3.3V Operation
♦
Industrial Temperature Range: -40°C to +85°C
♦
Underwriters Laboratories (UL) Recognized
Ordering Information
PART
DS1318E+
DS1318E+T&R
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
24 TSSOP
24 TSSOP
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
Typical Operating Circuit
TOP VIEW
V
CC
RPU
0.1μF
V
CC
SQW
EXT
X1
X2
GND
EXT
A3
A2
A1
A0
DQ0
DQ1
DQ2
GND
1
2
3
4
5
6
7
8
9
10
11
12
Pin Configuration
+
IRQ
WE
CPU
OE
CE
A3–A0
DQ–DQ7
GND
DS1318
V
BAT
X1
-
EXTERNAL
COUNTER
ENABLE
(EVENT TIMER)
DS1318
X2
24
23
22
21
20
19
18
17
16
15
14
13
V
CC
V
BAT
IRQ
SQW
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
TSSOP
(4.4mm)
______________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Parallel-Interface Elapsed Time Counter
DS1318
ABSOLUTE MAXIMUM RATINGS
Voltage Range on any Pin Relative to Ground ......-0.3V to +6.0V
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
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TSSOP (multilayer board)
Junction-to-Ambient Thermal Resistance (θ
JA
) ............72°C/W
Junction-to-Case Thermal Resistance (θ
JC
) .................13°C/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
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.) (Note 2)
PARAMETER
Supply Voltage
Battery Voltage
Logic 1 Voltage
Logic 0 Voltage
SYMBOL
V
CC
V
BAT
V
IH
V
IL
(Note 3)
(Note 3)
(Note 3)
(Note 3)
CONDITIONS
MIN
3.0
1.6
0.7 x
V
CC
-0.5
TYP
3.3
3.3
MAX
3.6
3.7
V
CC
+
0.5
+0.3 x
V
CC
UNITS
V
V
V
V
DC ELECTRICAL CHARACTERISTICS
(V
CC
= V
CC(MIN)
to V
CC(MAX)
, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
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