DALLAS DS1490F

Preliminary
DS1490F
2-in-1 Fob*
www.dalsemi.com
FEATURES
1-Wire® to USB port adapter for direct
connection to notebook and desktop
computers
Any iButton™ mounts in the ergonomically
angled handle for touch-and-go applications
such as door entry
Fast, convenient computer log on with data
rates up to142k bits/second from the 1-Wire
signal
USB guard protects the USB A connector
during everyday use conditions.
1.5M byte speed, low power, USB
1.2 compliant for plug and play operation
LED shines through translucent case to
indicate status
Both the 2-in-1 Fob and its resident iButton
are powered entirely from an USB interface
Fob sources up to 10 ma for powering 1-Wire
chips that require strong pull up such as the
Java™-powered or Thermochron iButton
Low Profile Blue Dot extends 1-Wire
signaling to other 1-Wire devices
✼
NOTE:
The DS1490F 2-in-1 Fob is sold without the
iButton to give choice of the desired iButton.
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101000
DS1490F
DESCRIPTION
The 2-in-1 Fob has a DS2490 chip in its handle to convert 1-Wire signaling to USB communication. In
this way an iButton, 1-Wire chip, or 1-Wire instrument can have a 2-way communication link with its
USB host. Any iButton from the lowest cost to the most sophisticated can be mounted in the angled end
of the fob. A Java-powered iButton in combination with the 2-in-1 Fob provides the equivalent of a Java
smart card with a built in reader. Everything fits in the handle, so there is no cable for the notebook
connectivity. The USB guard protects the connector from debris and mechanical stresses while attached
to a key ring. Pressing the eject latch releases the guard of the 2-in-1 Fob for USB connection.
Together with the appropriate USB device driver, a notebook or desktop computer can read/write the
attached iButton with no cables or other power connections. You can press the Blue Dot with your
iButton for touch-and-go door entry.
By snapping on the Low Profile Blue Dot (DS1402L) to the iButton on the 2-in-1 Fob, the range of the
1-Wire signal can be extended to another Blue Dot receptor or other 1-Wire devices.
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DS1490F
Dimensions
Schematic
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