DS1318 Datasheet, PDF (1/15 Pages) Dallas Semiconductor – Parallel-Interface Elapsed Time Counter

19-5664; Rev 1; 12/10
Parallel-Interface Elapsed Time Counter
General Description
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.
Power Meters
Industrial Controls
Servers
Applications
Typical Operating Circuit
V_CC
RPU
V_CC
SQW
IRQ
WE
EXT
OE
CPU
CE
DS1318
V_BAT
A3–A0
X1
DQ–DQ7
GND
X2
0.1μF
EXTERNAL
COUNTER
ENABLE
(EVENT TIMER)
Features
♦ 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
♦ +3.3V Operation
♦ Industrial Temperature Range: -40°C to +85°C
♦ Underwriters Laboratories (UL) Recognized
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
DS1318E+
-40°C to +85°C 24 TSSOP
DS1318E+T&R
-40°C to +85°C 24 TSSOP
+Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
Pin Configuration
TOP VIEW
X1
1+
X2
2
GND
3
EXT
4
A3
5
A2
6
A1
7
A0
8
DQ0
9
DQ1
10
DQ2
11
GND
12
DS1318
TSSOP
(4.4mm)
24
V_CC
23
V_BAT
22
IRQ
21
SQW
20
WE
19
OE
18
CE
17
DQ7
16
DQ6
15
DQ5
14
DQ4
13
DQ3
______________________________________________ Maxim Integrated Products 1
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or visit Maxim’s website at www.maxim-ic.com.