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Registered: ‎11-18-2017

How to check the FPGA chip (die) operating temperature in VIVADO? (KCU116)

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Hello.

 

I'm using Vivado 2018.2 and a KCU116 board which is equipped with Kintex UltraScale+ FPGA (xcku5p-ffvb676-2-e).

After implementation, I generated a bitstream and loaded it to the device (FPGA).

I want to check if my design works well within a certain temperature range (especially the FPGA operation temperature not the ambient temperature).

To intentionally control the voltage, I stopped the cooler which is on top of the FPGA (illustrated in figure 1) by pulling the plug (cooler)

and heated the FPGA with a hairdryer.

 

캡처3.JPG

[ figure 1 ]

 

I have few questions about the FPGA operating temperature.

 

question 1) 

In the Vivado 'HARDWARE MANAGER', there is a temperature indicator as below figure 2.

 

캡처2.JPG[ figure 2 ]

 

My question is what does that temperature means?

Is it the die (FPGA chip) operating temperature?

In 'UltraScale Architecture System Monitor' (UG580) page 7, in SYSMON Overview section, in the first sentence,

it is mentioned that "The SYSMON includes ... on-chip sensors ... such as temperature ... "

so I think it is the operating temperature other than the ambient temperature.

 

question 2)

In the 'KCU116 Evaluation Board User Guide' (UG1239), on page 8, in the Environmental section,

it is mentioned that the Operating temperature is between 0 C to +45 C.

My question is, is the operating temperature identical to the FPGA chip (die) temperature I mentioned in question 1) ?

If the temperature in figure 2 exceeds 45 C, does the board (or FPGA) malfunctions? 

 

question 3)

In the' UltraScale+ FPGAs Product Tables and Product Selection Guide' (https://www.xilinx.com/support/documentation/selection-guides/ultrascale-plus-fpga-product-selection-guide.pdf), on page 8, UltraScale+ Device Ordering Information is explained.

It is mentioned that the last character denotes the Temperature Grade.

In my KCU116 board, it has xcku5p-ffvb676-2-e.

So I could check that my FPGA in the board has a extended temperature grade.

It is mentioned that the junction temperature (Tj) is in the range of 0 C to +100 C for extended temperature grade FPGAs.

My question is, is the junction temperature (Tj) identical to the operating temperature I mentioned in question 1) and 2) ?

If it is the same, why is the temperature range different in 2 documents?

( As mentioned in question 2), the range is 0~45. However, as mentioned in question 3), the range is 0~100 ).

 

Thank you for your help.

 

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Registered: ‎01-22-2015

@kimjaewon 

My question is what does that temperature means?   Is it the die (FPGA chip) operating temperature?
The measurement is closely related to the FPGA junction temperature, Tj.  As described in the datasheet, DS922, for your XCKU5P:
Xilinx recommends measuring the Tj of a device using the system monitor as described in the UltraScale Architecture System Monitor User Guide (UG580). The system monitor temperature measurement errors (that are described in Table 78) must be accounted for in your design. For example, when using the system monitor with an external reference of 1.25V, and when the system monitor reports 97°C, there is a measurement error ±3°C. A reading of 97°C is considered the maximum adjusted Tj (100°C – 3°C = 97°C).

 

(UG1239).. it is mentioned that the Operating temperature is between 0 C to +45 C.  ..is the operating temperature identical to the FPGA chip (die) temperature I mentioned in question 1) ?  If the temperature in figure 2 exceeds 45 C, does the board (or FPGA) malfunctions?
The 0C-to-45C range in UG1239 is a recommended range for environment (ambient air) temperature.   What matters most is the Tj temperature – for which there are strict limits.  Table 2 of DS922 gives the recommended range of Tj for your FPGA.  If Tj goes outside this range, then the FPGA is not guaranteed to function properly.  Even more important is the absolute maximum value for Tj given in Table 1 of DS922.  If Tj exceeds the absolute maximum value from Table 1 then the FPGA can be damaged.

 

My question is, is the junction temperature (Tj) identical to the operating temperature I mentioned in question 1) and 2) ?  If it is the same, why is the temperature range different in 2 documents?
You need be concerned only about Tj.  If you stay within the Tj limits shown in Table 2 of DS922 then your FPGA will operate properly and will not be damaged.

Cheers,
Mark

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Registered: ‎01-22-2015

@kimjaewon 

My question is what does that temperature means?   Is it the die (FPGA chip) operating temperature?
The measurement is closely related to the FPGA junction temperature, Tj.  As described in the datasheet, DS922, for your XCKU5P:
Xilinx recommends measuring the Tj of a device using the system monitor as described in the UltraScale Architecture System Monitor User Guide (UG580). The system monitor temperature measurement errors (that are described in Table 78) must be accounted for in your design. For example, when using the system monitor with an external reference of 1.25V, and when the system monitor reports 97°C, there is a measurement error ±3°C. A reading of 97°C is considered the maximum adjusted Tj (100°C – 3°C = 97°C).

 

(UG1239).. it is mentioned that the Operating temperature is between 0 C to +45 C.  ..is the operating temperature identical to the FPGA chip (die) temperature I mentioned in question 1) ?  If the temperature in figure 2 exceeds 45 C, does the board (or FPGA) malfunctions?
The 0C-to-45C range in UG1239 is a recommended range for environment (ambient air) temperature.   What matters most is the Tj temperature – for which there are strict limits.  Table 2 of DS922 gives the recommended range of Tj for your FPGA.  If Tj goes outside this range, then the FPGA is not guaranteed to function properly.  Even more important is the absolute maximum value for Tj given in Table 1 of DS922.  If Tj exceeds the absolute maximum value from Table 1 then the FPGA can be damaged.

 

My question is, is the junction temperature (Tj) identical to the operating temperature I mentioned in question 1) and 2) ?  If it is the same, why is the temperature range different in 2 documents?
You need be concerned only about Tj.  If you stay within the Tj limits shown in Table 2 of DS922 then your FPGA will operate properly and will not be damaged.

Cheers,
Mark

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Registered: ‎11-18-2017

markg@prosensing.com 

Thank you very much for your reply.

 

Could you check if I understood your explanation correctly?

 

In figure 1, the temperature on the screen (I will put it as Ts) is 38.6 °C.

sysmontemp.JPG

 

 

 

 

 

 

 

 

 

 

 

 

[ figure 1 ]

So I could say that

"""

Ts is 38.6°C, so the junction temperature (Tj) is between 35.6 ~ 41.6 °C  (38.6±3°C ) because Tj=Ts±3°C.

I have to keep Tj (or Ts±3°C ) within the recommend temperature range (0 ~ 100°C) to guarantee proper function.

And I must keep Tj (or Ts±3°C ) below the maximum temperature (125°C) to prevent the FPGA from damaging.

"""

Did I understood correctly?

Thank you for your help.

 

ps.

Is the junction temperature same as operating temperature of the FPGA? (i.e. can I call the junction temperature (Tj) as operating temperature?) 

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Registered: ‎01-22-2015

@kimjaewon 

It appears that you have correctly launched SYSMON from the Vivado GUI since your screenshot is very similar to Figure 56 in UG908 (v2019.2). 

 

Ts is 38.6°C, so the junction temperature (Tj) is between 35.6 ~ 41.6 °C  (38.6±3°C ) because Tj=Ts±3°C.

I have to keep Tj (or Ts±3°C ) within the recommend temperature range (0 ~ 100°C) to guarantee proper function.

And I must keep Tj (or Ts±3°C ) below the maximum temperature (125°C) to prevent the FPGA from damaging.

Did I understood correctly?]
For an extended(E) temperature Kintex UltraScale+, you have correctly understood Xilinx document, DS922(v1.15).  However, above Tj=100C, the SYSMON and your ability to measure Tj may fail.  So, you strive to always keep Tj below 100C.

 

Is the junction temperature same as operating temperature of the FPGA? (i.e. can I call the junction temperature (Tj) as operating temperature?) 
To avoid confusion, and because Tj is so important, I would only call it the "FPGA junction temperature".  Note that "operating temperature" often refers to "environmental temperature", which is NOT equal to Tj.

 

As shown on page 7 of UG580(v1.9.1), there are other ways to monitor the temperature reported by SYSMON.  For example, you can use the Xilinx IP called the System Management Wizard that is described by document PG185.  This IP can be included in the HDL that you write for your XCKU5P, enabling you to monitor Tj in real-time.  If you have used the XADC Wizard for 7-Series FPGAs, then the System Management Wizard for UltraScale will look very familiar to you.