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SPECIAL FEATURES
256-bit Electrically Erasable Programmable
Read Only Memory (EEPROM)
communicates with the economy of one
signal plus ground
EEPROM organized as one 256-bit page
64-bit one-time programmable application
register is automatically write-protected after
programming
Reduces control, address, data, power, and
programming signals to a single data pin
8-bit family code specifies DS1971
communications requirements to reader
Reads and writes over a wide voltage range
of 2.8V to 6.0V from -40°C to +85°C
F3 MicroCan
F5 MicroCan
COMMON iButton FEATURES
Unique, factory-lasered and tested 64-bit
registration number (8-bit family code + 48-
bit serial number + 8-bit CRC tester) assures
absolute traceability because no two parts are
alike
Multidrop controller for MicroLAN
Digital identification and information by
momentary contact
Chip-based data carrier compactly stores
information
Data can be accessed while affixed to object
Economically communicates to bus master
with a single digital signal at 16.3kbps
Standard 16mm diameter and 1-Wire
protocol ensure compatibility with iButton
family
Button shape is self–aligning with cup-
shaped probes
Durable stainless steel case engraved with
registration number withstands harsh
environments
Easily affixed with self-stick adhesive
backing, latched by its flange, or locked with
a ring pressed onto its rim
Presence detector acknowledges when reader
first applies voltage
ORDERING INFORMATION
DS1971-F3+ F3 MicroCan
DS1971-F5+ F5 MicroCan
+Denotes a lead(Pb)-free/RoHS-compliant package.
EXAMPLES OF ACCESSORIES
DS9096P Self-Stick Adhesive Pad
DS9101 Multi-Purpose Clip
DS9093RA Mounting Lock Ring
DS9093F Snap-in Fob
DS9092 iButton Probe
DS1971
256-Bit EEPROM iButton
iButton and 1-Wire are registered trademarks of Maxim Integrated Products, Inc.
19-4734; Rev 7/09
DS1971
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iButton DESCRIPTION
The DS1971 256-bit EEPROM iButton is a rugged read/write data carrier that identifies and stores
relevant information about the product or person to which it is attached. This information can be accessed
with minimal hardware: for example, a single port pin of a microcontroller. The DS1971 consists of a
factory-lasered registration number that includes a unique 48-bit serial number, an 8-bit CRC, and an
8-bit Family Code (14H) plus 256 bits of EEPROM. The power to program and read the DS1971 is
derived entirely from the 1-Wire communication line. Data is transferred serially via the 1-Wire protocol
which requires only a single data lead and a ground return. The 48-bit serial number that is factory-
lasered into each DS1971 provides a guaranteed unique identity which allows for absolute traceability.
The durable MicroCan package is highly resistant to harsh environments such as dirt, moisture, and
shock. Its compact button-shaped profile is self-aligning with cup-shaped receptacles, allowing the
DS1971 to be used easily by human operators or automatic equipment. Accessories permit the DS1971 to
be mounted on printed circuit boards, plastic key fobs, photo-ID badges, ID bracelets, and many other
objects. Applications include work-in-progress tracking, electronic travelers, access control and storage of
calibration constants.
OVERVIEW
The block diagram in Figure 1 shows the relationships between the major control and memory sections of
the DS1971. The DS1971 has four main data components: 1) 64-bit lasered ROM, 2) 256-bit EEPROM
data memory with scratchpad, 3) 64-bit one-time programmable application register with scratchpad, and
4) 8-bit status memory. The bus master must first provide one of the ROM Function Commands before
the memory functions become accessible. All data is read and written least significant bit first.
The DS1971 contains the same memory chip as the DS2430A. For a full description of the logical
behavior, refer to the DS2430A data sheet.
DS1971
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DS1971 BLOCK DIAGRAM Figure 1
DS1971
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Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim
reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
REVISION HISTORY
REVISION
DATE DESCRIPTION PAGES
CHANGED
071508 Updated the F3 MicroCan and F5 MicroCan face brands with the latest
per PCN H020201. 1
7/09 Conversion to lead(Pb)-free; removal of bullet “Designed to meet
UL#913 (4th Edit.)….” 1
