Temperature sensing diode on Vertex 4

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

Reply to
Vassili Savinov
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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

Reply to
Bob

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

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Vassili Sav> 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?

Reply to
Austin Lesea

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