Datasheet

Thermochron iButton Device
4 Maxim Integrated
DS1921G
Note 17: 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 fail-
ure 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.
Note 18: The number of temperature conversions (= samples) possible with the built-in energy source depends on the operating and
storage temperature of the device. When not in use for a mission, the RTC oscillator should be turned off and the device
should be stored at a temperature not exceeding +25°C. Under this condition the shelf life time is 10 years minimum.
COMPARISON TABLE
LEGACY VALUES DS1921G VALUES
STANDARD SPEED (μs) OVERDRIVE SPEED (μs) STANDARD SPEED (μs) OVERDRIVE SPEED (μs)
PARAMETER
MIN MAX MIN MAX MIN MAX MIN MAX
t
SLOT
(including
t
REC
)
61 (undefined) 7 (undefined) 65* (undefined) 8* (undefined)
t
RSTL
480 (undefined) 48 80 540 640 58 80
t
PDH
15 60 2 6 15 60 1.1 6
t
PDL
60 240 8 24 60 270 7.5 32
t
W0L
60 120 6 16 60 120 8.5 15
iButton CAN PHYSICAL SPECIFICATION
SIZE See the Package Information section.
WEIGHT Ca. 3.3g
* Intentional change; longer recovery time between time slots.
Note: Numbers in bold are not in compliance with the published iButton device standards.
ELECTRICAL CHARACTERISTICS (continued)
(V
PUP
= +2.8V to +5.25V, T
A
= -40°C to +85°C.)