PRELIMINARY
DS1904
RTC iButton
www.iButton.com
SPECIAL FEATURES
ꢀ Presence detector acknowledges when reader
first applies voltage
ꢀ Meets UL#913 (4th Edit.); Intrinsically Safe
Apparatus, Approved under Entity Concept
for use in Class I, Division 1, Group A, B, C
and D Locations (application pending)
ꢀ Real-Time Clock/calendar in binary format
ꢀ Uses the same binary time/date representation
as the DS1994 but with 1 second resolution
ꢀ Clock accuracy is better than ± 2 minutes per
month at 25°C
ꢀ Operating temperature range from -40°C to
+70°C
ꢀ Over 10 years of operation
F5 MicroCan
5.89
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
0.36
0.51
16.25
YYWW REGISTERED RR
40
24
17.35
ꢀ Multidrop controller for MicroLAN
ꢀ Digital identification and information by
momentary contact
000000FBC52B
DATA
ꢀ Chip-based data carrier compactly stores in-
formation
GROUND
ꢀ Data can be accessed while affixed to object
ꢀ Economically communicates to host with a
single digital signal at 16.3k bits per second
ꢀ Standard 16 mm diameter and 1-Wire proto-
col ensure compatibility with iButton Device
family
ꢀ Button shape is self-aligning with cup-shaped
probes
ꢀ Durable stainless steel case engraved with
registration number withstands harsh envi-
ronments
All dimensions are shown in millimeters
ORDERING INFORMATION
DS1904L-F5
F5 MicroCan
EXAMPLES OF ACCESSORIES
DS9096P
DS9101
DS9093RA
DS9093A
DS9092
Self-Stick Adhesive Pad
Multi-Purpose Clip
Mounting Lock Ring
Snap-In Fob
iButton Probe
ꢀ Easily affixed with self-stick adhesive back-
ing, latched by its flange, or locked with a
ring pressed onto its rim
iButton DESCRIPTION
The DS1904 RTC iButton is a rugged real-time clock module that can be accessed with minimal
hardware. Data is transferred serially via the 1-Wire protocol, which requires only a single data lead and a
ground return. The DS1904 contains a unique 64-bit factory-lasered ROM and a real-time clock/calendar
implemented as a binary counter. The durable MicroCan package is highly resistant to environmental
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