DS1921G Maxim, DS1921G Datasheet - Page 7

• Manufacturer Part Number: DS1921G
• Description: The DS1921G Thermochron® iButton® is a rugged, self-sufficient system that measures temperature and records the result in a protected memory section
• Manufacturer: Maxim

The DS1921G Thermochron iButton is an ideal device
to monitor the temperature of any object it is attached
to or shipped with, such as perishable goods or con-
tainers of temperature-sensitive chemicals. The
read/write NV memory can store an electronic copy of
shipping information, date of manufacture and other
important data written as clear as well as encrypted
files. Note that the initial sealing level of the DS1921G
achieves IP56. Aging and use conditions can degrade
the integrity of the seal over time, therefore, for applica-
tions with significant exposure to liquids, sprays, or
other similar environments, it is recommended to place
Figure 1. Block Diagram
_______________________________________________________________________________________
TEMPERATURE
OSCILLATOR
Detailed Description
32.768kHz
1-Wire PORT
CORE
DS1921G
IO
3V LITHIUM
CONTROL REGISTERS,
AND COUNTERS
CONTROL
TIMEKEEPING,
LOGIC
INTERNAL
FUNCTION
CONTROL
ROM
ALARM TIMESTAMP AND
DURATION LOGGING
DATA-LOG MEMORY
GENERAL-PURPOSE
REGISTER PAGE
the Thermochron in the DS9107 iButton capsule. The
DS9107 provides a watertight enclosure that has been
rated to IP68 (refer to Application Note 4126:
Understanding the IP (Ingress Protection) Ratings of
iButton Data Loggers and Capsule ).
Figure 1 shows the relationships between the major
control and memory sections of the DS1921G. The
device has seven main data components: 64-bit
lasered ROM; 256-bit scratchpad; 4096-bit general-
purpose SRAM; 256-bit register page of timekeeping,
control, and counter registers; 96 bytes of alarm time-
stamp and duration logging memory; 126 bytes of
HISTOGRAM
MEMORY
MEMORY
SRAM
LASERED
Thermochron iButton
64-BIT
ROM
FUNCTION
CONTROL
MEMORY
PARASITE-POWERED
CIRCUITRY
SCRATCHPAD
256-BIT
Overview
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