Am 25.11.2016 um 14:53 schrieb H. Nikolaus Schaller hns@goldelico.com:
Hi,
Am 25.11.2016 um 14:47 schrieb Urja Rannikko urjaman@gmail.com:
Hi and sorry for interjecting like this, but ...
no problem.
On Fri, Nov 25, 2016 at 3:28 PM, Michael Mrozek EvilDragon@openpandora.org wrote:
Am Fri, 25 Nov 2016 13:35:29 +0100 hat "H. Nikolaus Schaller" hns@goldelico.com geschrieben:
Can you try setting the voltage to something lower (like 0,75V)?
Because that's what still worked with 1GHz and Highload (and that's REALLY undervolting it), so the question is whether there's maybe some limiter somewhere.
This, and ...
I have done this test by soldering a wire to the PALMAS SMPS123 outputs
Could you try to find some place more focused on what the OMAP5 is "receiving"?
Unfortunately no chance since power distribution is in inner PCB layers and comes to the surface under the OMAP chip. So there is no chance to solder wires there...
I should also note that we already have measured the resistance between the PALMAS and the OMAP an it is approx. 10mOhm. So running 5 Amperes through this changes voltage by 50mV which is half of an OPP step (100mV).
What we don't know is the resistance between PCB and the Si chip itself introduced by BGA balls and whatever is inside the chip.