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.
Applications
Power Meters
Industrial Controls
Servers
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
DS1318
Parallel-Interface Elapsed Time Counter
______________________________________________ Maxim Integrated Products
1
DS1318
GND
24
23
22
21
20
19
18
17
16
15
X1
TOP VIEW
X2
V
BAT
V
CC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
TSSOP
DQ2
DQ1
DQ0
A0
A1
A2
A3
1
2
3
4
5
10
9
8
7
6
11
12
14
13
SQW
IRQ
EXT
GND
Pin Configuration
Ordering Information
DS1318
-
CPU
V
CC
V
CC
DQDQ7
A3A0
GND
RPU
SQW
X1
IRQ
WE
OE
CE
X2
EXT
EXTERNAL
COUNTER
ENABLE
(EVENT TIMER)
0.1
µF
V
BAT
Typical Operating Circuit
Rev 0; 2/04
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
DS1318
-40°C to +85°C
24 TSSOP,
4.4mm
DS1318
DS1318
Parallel-Interface Elapsed Time Counter
2
_____________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
RECOMMENDED DC OPERATING CONDITIONS
(V
CC
= V
CC(MIN)
to V
CC(MAX)
, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 1)
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.
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
Soldering Temperature ......................................See IPC/JEDEC
J-STD-020A Specification
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage
V
CC
(Note 2)
3.0
3.3
3.6
V
Battery Voltage
V
CC
(Note 2)
1.6
3.3
3.7
V
Logic 1 Voltage
V
IH
(Note 2)
0.7 x
V
CC
V
CC
+
0.5
V
Logic 0 Voltage
V
IL
(Note 2)
-0.5
+0.3 x
V
CC
V
DC ELECTRICAL CHARACTERISTICS
(V
CC
= V
CC(MIN)
to V
CC(MAX)
, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Logic 0 Output Current
(V
OL
= 0.15 x V
CC
)
I
OL
3
mA
Logic 1 Output Current
(V
OH
= 0.85 x V
CC
)
I
OH
1
mA
SQW, INT Logic 0 Output
(V
OL
= 0.15 x V
CC
)
I
OLSI
5
mA
Input Leakage
I
LI
(Note 3)
1
µA
I/O Leakage
I
LO
(Note 4)
-1
+1
µA
Active Supply Current
I
CCA
(Note 5)
10
mA
Standby Current
I
CCS
(Note 6)
100
150
µA
Battery Input-Leakage Current
I
BATLKG
10
100
nA
Power-Fail Voltage
V
PF
(Note 2)
2.70
2.97
V
DS1318
Parallel-Interface Elapsed Time Counter
_____________________________________________________________________
3
AC ELECTRICAL CHARACTERISTICS
(V
CC
= V
CC
(
MIN)
to V
CC(MAX)
, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Read Cycle Time
t
RC
80
ns
Address Access Time
t
AA
80
ns
CE to DQ Low-Z
t
CEL
0
ns
CE Access Time
t
CEA
80
ns
CE Data Off-Time
t
CEZ
30
ns
OE to DQ Low-Z
t
OEL
0
ns
OE Access Time
t
OEA
70
ns
OE Data Off-Time
t
OEZ
30
ns
Output Hold from Address
t
OH
5
ns
Write Cycle Time
t
WC
80
ns
Address Setup Time
t
AS
0
ns
WE Pulse Width
t
WEW
40
ns
CE Pulse Width
t
CEW
70
ns
Data Setup Time
t
DS
40
ns
Data Hold Time
t
DH
0
ns
Address Hold Time
t
AH
0
ns
WE Data Off-Time
t
WEZ
30
ns
Write Recovery Time
t
WR
10
ns
Oscillator Stop Flag (OSF) Delay
t
OSF
(Note 8)
4
ms
DC ELECTRICAL CHARACTERISTICS
(V
CC
= 0V, V
BACKUP
= 3.7V, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Battery Input Current
(ENOSC = 1)
I
BAT
(Note 7)
750
1100
nA
Battery Input Current
(ENOSC = 0)
I
BATDR
(Note 7)
100
nA
DS1318
Parallel-Interface Elapsed Time Counter
4
_____________________________________________________________________
VALID
DQ0DQ7
OE
CE
A0A4
t
RC
t
AA
t
CEA
t
CEZ
t
OH
t
OEZ
t
OEL
t
CEL
t
OEA
Read Cycle Timing
t
WC
t
WEW
t
WEZ
t
DS
t
DH
t
WR
t
AS
t
AS
t
AH
DATA INPUT
DQ0DQ7
WE
CE
A0A4
DATA OUTPUT
DATA INPUT
VALID
VALID
Write Cycle Timing, Write-Enable Controlled
t
WC
t
DS
t
DH
t
WR
t
AS
t
AS
t
CEW
t
AH
DATA INPUT
DQ0DQ7
WE
CE
A0A4
DATA INPUT
VALID
VALID
Write Cycle Timing, Chip-Enable Controlled
DS1318
Parallel-Interface Elapsed Time Counter
_____________________________________________________________________
5
HIGH-Z
DON'T CARE
t
VCCR
t
REC
VALID
RECOGNIZED
RECOGNIZED
VALID
V
CC
V
PF(MAX)
V
PF(MIN)
t
VCCF
INPUTS
OUTPUTS
Power-Up/Power-Down Timing
POWER-UP/POWER-DOWN CHARACTERISTICS
(T
A
= -40°C to +85°C) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Recovery at Power-Up
t
REC
(Note 9)
150
ms
V
CC
Fall Time; V
PF(MAX)
to
V
PF(MIN)
t
VCCF
300
µs
V
CC
Rise Time; V
PF(MIN)
to
V
PF(MAX)
t
VCCR
0
µs
CAPACITANCE
(T
A
= +25°C)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Capacitance on All Input Pins
C
IN
10
pF
Capacitance on
IRQ, SQW, and
DQ Pins
C
IO
10
pF
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