Z87X-UD5H favorite spot of Gigabyte at installing motherboard temperature sensor?


Well-Known Member
After a good visual inspection, and even after reviewing GA-Z87X-UD5H the actual repair_manual, I am still unable to physically locate the so called as motherboard temperature sensor.
Gigabyte uses the actual description of SYSTEM Temperature.

CPU along PCH, these two are both on-chip sensors, but system temperature, this in theory it should be a thermocouple placed somewhere along the motherboard.
Any incoming insights are welcome.
Such "system temperature" is also often read from an on-chip sensor located inside the SIO/LPC chip.
I found some solid clues. ITE IT8728F is the one collecting information from SYS_TEMP + PCH_TEMP

ITE IT8728F schematic talks about temperature input this converted to voltage due a thermal diode, Gigabyte using the cheapest method due a 10K SMT resistor (+Reference comparison circuit).

Both SYS_TEMP + PCH_TEMP they use as sensor a regular 10K resistor placed at strategically selected distance from the critical component.

And this is not all, IR3563B Mosfet control circuit, this also uses two identical sensors too:
1) Placed close to Vcore output inductor
2) Placed close to DDR memory output inductor
High temperature alert will force the circuit to stop driving any MOSFET = This works as electrical protection feature = thermal fuse.

IT8790E this also include three inputs of temperature, it monitor in parallel SYS_TEMP + PCH_TEMP + the temperature of a single MOSFET for the PCH, possibly another one yet electrical protection feature = thermal fuse.

In summary, most popular places to add a thermal sensor over a PCB, this is next to single MOSFET or next to output inductor (pairs of MOSFET), or next to PCH chip.
CPU this is the only component delivering directly temperature data at ITE IT8728F.
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