Operating Temperature Range ........................+15°C to +140°C
Junction Temperature ......................................................+150°C
Storage Temperature Range............................-25°C to +140°C*
*Storage
or operation above +50°C significantly reduces battery life with an upper limit of 300hr cumulative at +140°C. The recom-
mended storage temperature for maximum battery lifetime is between +5°C and +35°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.
Electrical Characteristics
PARAMETER
Operating Temperature
I/O PIN GENERAL DATA
1-Wire Pullup Resistance
Input Capacitance
Input Load Current
High-to-Low Switching Threshold
Input Low Voltage
Low-to-High Switching Threshold
Switching Hysteresis
Output Low Voltage
T
A
(V
PUP
= 3.0V to 5.25V, unless otherwise noted.)
SYMBOL
CONDITIONS
DS1922E (Note 1)
(Notes 2, 3)
(Note 4)
I/O pin at V
PUP
(Notes 5, 6)
(Notes 2, 7)
(Notes 5, 8)
(Note 9)
At 4mA (Note 10)
Standard speed, R
PUP
= 2.2k
Recovery Time
(Note 2)
t
REC
Overdrive speed, R
PUP
= 2.2k
Overdrive speed, directly prior to reset
pulse; R
PUP
= 2.2k
t
REH
t
SLOT
(Note 11)
Standard speed
Time Slot Duration (Note 2)
Overdrive speed, V
PUP
> 4.5V
Overdrive speed (Note 12)
Standard speed, V
PUP
> 4.5V
Standard speed (Note 12)
Reset Low Time (Note 2)
t
RSTL
Overdrive speed, V
PUP
> 4.5V
Overdrive speed (Note 12)
Presence-Detect High Time
t
PDH
Standard speed, V
PUP
> 4.5V
Standard speed (Note 12)
Overdrive speed (Note 12)
5
2
µs
5
0.6
65
8
9.5
480
690
48
70
15
15
2
720
720
µs
80
80
60
63.5
7
µs
µs
2.0
µs
0.7
0.09
0.4
100
6
MIN
+15
TYP
MAX
+140
2.2
800
10
3.2
0.3
3.4
N/A
0.4
UNITS
°C
k
pF
µA
V
V
V
V
V
R
PUP
C
IO
I
L
V
TL
V
IL
V
TH
V
HY
V
OL
Rising-Edge Hold-Off Time
I/O PIN 1-Wire RESET, PRESENCE-DETECT CYCLE
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(
Maxim Integrated | 2
2
2.0
S
T
O
65
µs
DS1922E
R
S
iButton High-Temperature Logger
480
720
with 8KB Datalog Memory
80
60
6
7
MIN
1.5
1.5
0.15
60
60
7
7
65
71.5
8
60
6
7.5
5
1
5
1
t
RL
+
t
RL
+
TYP
MAX
5
8
1
240
287
24
28
75
75
9
120
12
12
15
µs
1.95
15 -
µs
1.95 -
15
µs
1.95
µs
µs
µs
µs
UNITS
Electrical Characteristics (continued)
S
(V
PUP
= 3.0V to 5.25V, unless otherwise noted.)
PARAMETER
Presence-Detect Fall Time
(Note 13)
SYMBOL
t
FPD
CONDITIONS
Standard speed, V
PUP
> 4.5V
Standard speed
Overdrive speed
Standard speed, V
PUP
> 4.5V
Standard speed (Note 12)
Presence-Detect Low Time
t
PDL
Overdrive speed, V
PUP
> 4.5V (Note 12)
Overdrive speed (Note 12)
Standard speed, V
PUP
> 4.5V
Standard speed
Overdrive speed
Presence-Detect Sample Time
(Note 2)
I/O PIN 1-Wire WRITE
t
MSP
Standard speed
Write-Zero Low Time
(Notes 2, 14)
Write-One Low Time
(Notes 2, 14)
I/O PIN 1-Wire READ
Read Low Time
(Notes 2, 15)
Read Sample Time
(Notes 2, 15)
REAL-TIME CLOCK (RTC)
Accuracy
Frequency Deviation
TEMPERATURE CONVERTER
Conversion Time
(Note 16)
Thermal Response Time
Constant (Note 17)
Conversion Error (Notes 18, 19)
+110°C to +140°C
Temperature Cycles
Operating Lifetime
N
TCY
t
LIFE
Cycle = ramp from +25°C to > +125°C
and back to +25°C (Note 21)
Temperature > +125°C (Note 21)
8-bit mode
t
CONV
16-bit mode (11 bits)
Can package
+15°C to +110°C (Note 20)
F
t
W0L
Overdrive speed, V
PUP
> 4.5V (Note 12)
Overdrive speed (Note 12)
Standard speed
Overdrive speed
Standard speed
t
W1L
t
RL
t
MSR
Overdrive speed
Standard speed
Overdrive speed
See the
RTC Accuracy
graph
0°C to +125°C
-600
30
240
130
±7
+60
75
Min/
Month
ppm
ms
600
s
°C
-1.5
+1.5
300
300
Cycles
Hours
RESP
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Maxim Integrated | 3
DS1922E
iButton High-Temperature Logger
with 8KB Datalog Memory
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
Note 13:
Note 14:
Note 15:
Note 16:
Note 17:
Note 18:
Note 19:
Note 20:
Note 21:
Operation above +125°C is restricted to mission operations only. Communication and 1-Wire pin specifications are not
specified for operation above +125°C.
System requirement.
Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1-Wire recovery
times. The specified value here applies to systems with only one device and with the minimum 1-Wire recovery times. For
more heavily loaded systems, an active pullup such as that in the DS2480B can be required.
Capacitance on the data pin could be 800pF when V
PUP
is first applied. If a 2.2k resistor is used to pull up the data line
2.5µs after V
PUP
has been applied, the parasite capacitance does not affect normal communications.
V
TL
and V
TH
are a function of the internal supply voltage, which is a function of V
PUP
and the 1-Wire recovery times. The
V
TH
and V
TL
maximum specifications are valid at V
PUPMAX
(5.25V). In any case, V
TL
< V
TH
< V
PUP
.
Voltage below which, during a falling edge on I/O, a logic 0 is detected.
The voltage on I/O must be less than or equal to V
ILMAX
whenever the master drives the line low.
Voltage above which, during a rising edge on I/O, a logic 1 is detected.
After V
TH
is crossed during a rising edge on I/O, the voltage on I/O must drop by V
HY
to be detected as logic 0.
The I-V characteristic is linear for voltages less than 1V.
The earliest recognition of a negative edge is possible at t
REH
after V
TH
has been previously reached.
Numbers in
bold
are
not
in compliance with the published iButton device standards. See the
Comparison Table.
Interval during the negative edge on I/O at the beginning of a presence-detect pulse between the time at which the volt-
age is 90% of V
PUP
and the time at which the voltage is 10% of V
PUP
.
e
in Figure 13 represents the time required for the pullup circuitry to pull the voltage on I/O up from V
IL
to V
TH
. The actual
maximum duration for the master to pull the line low is t
W1LMAX
+ t
F
-
e
and t
W0LMAX
+ t
F
-
e,
respectively.
d
in Figure 13 represents the time required for the pullup circuitry to pull the voltage on I/O up from V
IL
to the input high
threshold of the bus master. The actual maximum duration for the master to pull the line low is t
RLMAX
+ t
F
.
To conserve battery power, use 8-bit temperature logging whenever possible.
This number was derived from a test conducted by Cemagref in Antony, France, in July 2000:
www.cemagref.fr/English/index.htm Test Report No. E42.
Includes +0.1°C/-0.2°C calibration chamber measurement uncertainty.
Warning:
Maxim data-logger products are 100% tested and calibrated at time of manufacture to ensure that they meet all
data sheet parameters, including temperature accuracy. As with any sensor-based product, user shall be responsible for
occasionally rechecking the temperature accuracy of the product to ensure it is still operating properly. Furthermore, as
with all products of this type, when deployed in the field and subjected to handling, harsh environments, or other hazards/
use conditions, there may be some extremely small but nonzero logger failure rate. In applications where the failure of any
logger is a concern, user shall assure that redundant (or other primary) methods of testing and determining the handling
methods, quality, and fitness of the articles and products are implemented to further mitigate any risk.
Guaranteed by design and not production tested.
Devices leave the factory after having been run through a few cycles above +125°C. This is required for calibration of the
device but should not affect lifetime of the device as specified. However, this process results in a nonzero value in the
Device Samples Counter register (0223h–0225h), which provides evidence the device has been factory calibrated.
www.maximintegrated.com
Maxim Integrated | 4
DS1922E
Comparison Table
PARAMETER
iButton High-Temperature Logger
with 8KB Datalog Memory
LEGACY VALUES
OVERDRIVE SPEED
(µs)
MIN
7
48
2
8
6
MAX
(undefined)
80
6
24
16
DS1922E VALUES
STANDARD SPEED
(µs)
MIN
65
*
STANDARD SPEED
(µs)
MIN
MAX
(undefined)
(undefined)
60
240
120
61
480
15
60
60
OVERDRIVE SPEED
(µs)
MIN
9.5
70
2
7
7.5
MAX
(undefined)
80
7
28
12
MAX
(undefined)
720
63.5
287
120
t
SLOT
(including t
REC
)
t
RSTL
t
PDH
t
PDL
t
W0L
690
15
60
60
*Intentional
change; longer recovery time requirement due to modified 1-Wire front-end.
Note:
Numbers in
bold
are
not
in compliance with the published iButton device standards.
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