Answers Database


Virtex: What are the temperature sensing diode pins (DXP and DXN)?


Record #5738

Product Family: Hardware

Product Line: Virtex

Product Part: V300

Problem Title:
Virtex: What are the temperature sensing diode pins (DXP and DXN)?


Problem Description:
Urgency: Standard

General Description: This solution describes what the temperature
sensing diodes pins (DXP and DXN) are and what considerations
must be taken when using them.


Solution 1:

One feature found in the Virtex family is a temperature sensing diode.
This new feature can be accessed through the DXP (Anode) and
DXN (Cathode) pins.  The DXP and DXN pins are connected to a
diode-connected transistor which create a remote sensor.   These
additional pins are not available on all packages.

The DXP and DXN pins are dedicated pins and cannot be accessed
through the software tools. These pins are always available and
nothing special needs to be done in the design. If the temperature
sensing feature is not used, then the DXP and DXN pins can be left
unconnected.

The temperature sensing diode is only one part of a two part system,
which incorporates a Temperature Sensor Interface Chip.

To complete the system, you will need a Temparature Sensor device
as well, which will be connected to the Virtex device via the DXP
and DXN pins. On most Temperature Sensing devices, there are
corresponding pins which will connect to DXP and DXN. The user
can then set the upper and lower limits and the Temperature Sensor
will create an interrupt when these bounds have been exceeded.
The interrupt is simply an output pin on the Sensor. This output
could then be used to turn off the clock or turn on a fan for example to
reduce heat.

One such Temperature Sensor is the Maxim 1617 Remote/Local Temperature
Sensor with SMBus Serial Interface. For more information regarding this
device, please refer to http://www.maxim-ic.comInternet Link (or for the datasheets,
visit http://209.1.238.250/arpdf/1855.pdfInternet Link).




End of Record #5738 - Last Modified: 03/31/99 13:14

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