[PIC] [EE] Internal RC sensitive to PCB flex?

[Van Horn, David]

Is there any documentation on sensitivity to PCB flex when using the internal RC?
I have seen this on SAM7 chips and I think it's happening on a 24F chip.

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO 80301 USA
phone: [phone] x110
email: ***@backcountryaccess.com<mailto:***@backcountryaccess.com>

[Sean Breheny]

I don't know about documentation but I have seen this before but I cannot
remember whether it was with a 16F88 or dsPIC24. I noticed it only when I
applied pressure directly to the package of the chip, though. I would
suspect that anything which applies pressure to the die will change the
value of resistors and capacitors on the die.



On Thu, Nov 2, 2017 at 5:01 PM, Van Horn, David <

Post by Van Horn, David
Is there any documentation on sensitivity to PCB flex when using the internal RC?
I have seen this on SAM7 chips and I think it's happening on a 24F chip.
--
David VanHorn
Lead Hardware Engineer
Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO 80301 USA
phone: [phone] x110
backcountryaccess.com>
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[Van Horn, David]

I verified yesterday that it is happening, and that it's not just temperature. On external crystal a pin toggle based on a timer is dead constant. On internal RC, applying torque to the board wobbles the oscillator like a theremin.


-----Original Message-----
From: piclist-***@mit.edu [mailto:piclist-***@mit.edu] On Behalf Of Sean Breheny
Sent: Thursday, November 2, 2017 4:47 PM
To: Microcontroller discussion list - Public.
Subject: Re: [PIC] [EE] Internal RC sensitive to PCB flex?

I don't know about documentation but I have seen this before but I cannot remember whether it was with a 16F88 or dsPIC24. I noticed it only when I applied pressure directly to the package of the chip, though. I would suspect that anything which applies pressure to the die will change the value of resistors and capacitors on the die.

Post by Van Horn, David
Is there any documentation on sensitivity to PCB flex when using the internal RC?
I have seen this on SAM7 chips and I think it's happening on a 24F chip.
--
David VanHorn
Lead Hardware Engineer
Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO 80301 USA
phone: [phone] x110
backcountryaccess.com>
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

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