Temperature sensing diode on Vertex 4

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I will be using Vertex 4 (LX60) in my project this chip has two pins TDN_0 and
TDP_0 which are supposed to be connected to temperature sensing diode. Can I
leave them unconnected? If not what sort of diode should it be?

Thank you. Vassili Savinov

Re: Temperature sensing diode on Vertex 4

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First, read the Xilinx literature. You'll see that those two pins ARE the
sensing diode. They indicate what the FPGA junction temperature is.

Bob



Re: Temperature sensing diode on Vertex 4
Vassili,

The diode pins are subject to ESD damage if they do not get connected to
anything.  So we recommend grounding them if not used.  That way if at
some point in the future, you wanted to use them, it is unlikely they
would be bad.

The diode is just a lateral pnp transistor emitter base junction, and is
designed to be used with the two current switched sensors sold for
Penitums by National, Micrel, and others.

We try to make the ideality factor, and series resistance the same as a
Pentium 3, but we are only close to, not at, the values.

This results in a 1 or 2 degree C offset and error over temperature.

The Rs and I factors are in the datasheet, and can be used with some
temp sensor ICs where these two factors can be programmed in.

Austin
http://www.national.com/pf/LM/LM63.html
http://www.edn.com/article/CA307863.html


Vassili Savinov wrote:

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TDP_0 which are supposed to be connected to temperature sensing diode. Can I
leave them unconnected? If not what sort of diode should it be?
Quoted text here. Click to load it

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