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Hello,

I am hoping that someone can explain the damaged caused by applying
5VDC to VDD1,VDD2, and VDDPLL while the Internal Voltage Regulator is
enabled. On a small run of a project using an MC9S12DG128 with
Pierce osc configuration we incorrectly supplied 5VDC to the internal
voltage regulator filter pins. These boards all worked properly upon
intial programming. However, we have had a high failure rate in the
field with processors failing to start or unreliably starting after
several weeks of use. I suspect the problem is damage to the silicon
and VCO circuitry and would appreciate some expert opinions.

On one such processor that failed in the field I have noticed the
following--

With 5VDC still applied to VDD1, VDD2 and VDDPLL the unit boots in
the lab, and I am able to use a BDM debugger.

When I disconnected 5VDC from these pins and placed 100nf caps, all
three outputs measure 2.5VDC. However, the oscillator does not
appear to start correctly and I can not connect with a BDM pod. The
mcu will only start if 5VDC is aplied to all three of these pins.

On a new design with this problem corrected, mcu boot normall using
identical components on the oscillator and vco, so I suspect that the
unit above does have some damage to the silicon.

Thanks in advance,
Dan
------------------------------------



(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

Hi,
The manual states in Appendix: Electrical Characteristics the followings:
1. The device contains an internal voltage regulator to generate the logic
and PLL supply out of the I/O supply. The absolute maximum ratings
apply when the device is powered from an external source.
The maximum allowed: 3V .
2. Also: for VDD1 and VDD2:
Internal power and ground generated by internal regulator. These also
allow an external source VDD1, VDD2 to supply the core Vdd /Vss
voltages and bypass the internal voltage regulator. Nominal voltage: 2.5V !!

So, it is quite normally to have unexpected behavior.
Regards,
IP

danazari001 wrote:
>
> Hello,
>
> I am hoping that someone can explain the damaged caused by applying
> 5VDC to VDD1,VDD2, and VDDPLL while the Internal Voltage Regulator is
> enabled. On a small run of a project using an MC9S12DG128 with
> Pierce osc configuration we incorrectly supplied 5VDC to the internal
> voltage regulator filter pins. These boards all worked properly upon
> intial programming. However, we have had a high failure rate in the
> field with processors failing to start or unreliably starting after
> several weeks of use. I suspect the problem is damage to the silicon
> and VCO circuitry and would appreciate some expert opinions.
>
> On one such processor that failed in the field I have noticed the
> following--
>
> With 5VDC still applied to VDD1, VDD2 and VDDPLL the unit boots in
> the lab, and I am able to use a BDM debugger.
>
> When I disconnected 5VDC from these pins and placed 100nf caps, all
> three outputs measure 2.5VDC. However, the oscillator does not
> appear to start correctly and I can not connect with a BDM pod. The
> mcu will only start if 5VDC is aplied to all three of these pins.
>
> On a new design with this problem corrected, mcu boot normall using
> identical components on the oscillator and vco, so I suspect that the
> unit above does have some damage to the silicon.
>
> Thanks in advance,
> Dan
>
>

------------------------------------



(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

--- In 6...@yahoogroups.com, Petrescu wrote:
Thanks IP,

No doubt that I damaged the mcu. What I am hoping that someone could
explain is why the mcu now will ONLY work with the external 5VDC
applied to these pins? Although it is somewhat accademic at this
point, I'm currious as to what internal circuitry in particular has
been damaged. I am hoping that the behaviour I am seeing in field
can be fully explained by this connection error.

Thanks,
Dan
>
> Hi,
> The manual states in Appendix: Electrical Characteristics the
followings:
> 1. The device contains an internal voltage regulator to generate
the logic
> and PLL supply out of the I/O supply. The absolute maximum ratings
> apply when the device is powered from an external source.
> The maximum allowed: 3V .
> 2. Also: for VDD1 and VDD2:
> Internal power and ground generated by internal regulator. These
also
> allow an external source VDD1, VDD2 to supply the core Vdd /Vss
> voltages and bypass the internal voltage regulator. Nominal
voltage: 2.5V !!
>
> So, it is quite normally to have unexpected behavior.
> Regards,
> IP
>
------------------------------------

______________________________
Stellaris® MCU Family: New Parts, New Package, New Price.


(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

Hi,
At this stage I think only the chip designer who has an intimate
knowledge of
internal circuits can explain what you want.
Sorry, I do not understand:
"mcu now will ONLY work with the external 5VDC
applied to these pins"
is this behavior after you re-designed the board? Is the internal
regulator still
enabled or not? (and how did you enabled/disabled)?
Regards,
IP

danazari001 wrote:
>
> --- In 6...@yahoogroups.com ,
> Petrescu wrote:
> Thanks IP,
>
> No doubt that I damaged the mcu. What I am hoping that someone could
> explain is why the mcu now will ONLY work with the external 5VDC
> applied to these pins? Although it is somewhat accademic at this
> point, I'm currious as to what internal circuitry in particular has
> been damaged. I am hoping that the behaviour I am seeing in field
> can be fully explained by this connection error.
>
> Thanks,
> Dan
> >
> > Hi,
> > The manual states in Appendix: Electrical Characteristics the
> followings:
> > 1. The device contains an internal voltage regulator to generate
> the logic
> > and PLL supply out of the I/O supply. The absolute maximum ratings
> > apply when the device is powered from an external source.
> > The maximum allowed: 3V .
> > 2. Also: for VDD1 and VDD2:
> > Internal power and ground generated by internal regulator. These
> also
> > allow an external source VDD1, VDD2 to supply the core Vdd /Vss
> > voltages and bypass the internal voltage regulator. Nominal
> voltage: 2.5V !!
> >
> > So, it is quite normally to have unexpected behavior.
> > Regards,
> > IP
> >

------------------------------------

______________________________
Stellaris® MCU Family: New Parts, New Package, New Price.


(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

Hi IP,

The new board with the correct internal voltage regulator hookup
works correctly. What I meant to say is that a board that had 5VDC
applied to VDD1,VDD2 and VDDPLL, and is now presumbably damaged, will
now only work with 5VDC applied to all three pins. If I remove 5VDC
from these pins it stops working, even though I measure 2.5 VDC. I
am enabling the internal voltage regulator by holding VREGEN high.

Regards,
Dan

--- In 6...@yahoogroups.com, Petrescu wrote:
>
> Hi,
> At this stage I think only the chip designer who has an intimate
> knowledge of
> internal circuits can explain what you want.
> Sorry, I do not understand:
> "mcu now will ONLY work with the external 5VDC
> applied to these pins"
> is this behavior after you re-designed the board? Is the internal
> regulator still
> enabled or not? (and how did you enabled/disabled)?
> Regards,
> IP
>
> danazari001 wrote:
> >
> > --- In 6...@yahoogroups.com ,
> > Petrescu wrote:
> > Thanks IP,
> >
> > No doubt that I damaged the mcu. What I am hoping that someone
could
> > explain is why the mcu now will ONLY work with the external 5VDC
> > applied to these pins? Although it is somewhat accademic at this
> > point, I'm currious as to what internal circuitry in particular
has
> > been damaged. I am hoping that the behaviour I am seeing in field
> > can be fully explained by this connection error.
> >
> > Thanks,
> > Dan
> > >
> > > Hi,
> > > The manual states in Appendix: Electrical Characteristics the
> > followings:
> > > 1. The device contains an internal voltage regulator to generate
> > the logic
> > > and PLL supply out of the I/O supply. The absolute maximum
ratings
> > > apply when the device is powered from an external source.
> > > The maximum allowed: 3V .
> > > 2. Also: for VDD1 and VDD2:
> > > Internal power and ground generated by internal regulator. These
> > also
> > > allow an external source VDD1, VDD2 to supply the core Vdd /Vss
> > > voltages and bypass the internal voltage regulator. Nominal
> > voltage: 2.5V !!
> > >
> > > So, it is quite normally to have unexpected behavior.
> > > Regards,
> > > IP
> > >
> >
>
------------------------------------



(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

Hi,
OK, I understand - in this case my first sentence from previous mail
still remain, since in the user manual there is only a block diagram.
If you are looking for minimum changes on 'old' boards, try VREGEN=L
and maintain the board as is and see if it works OK.
Regards,
IP
danazari001 wrote:
>
> Hi IP,
>
> The new board with the correct internal voltage regulator hookup
> works correctly. What I meant to say is that a board that had 5VDC
> applied to VDD1,VDD2 and VDDPLL, and is now presumbably damaged, will
> now only work with 5VDC applied to all three pins. If I remove 5VDC
> from these pins it stops working, even though I measure 2.5 VDC. I
> am enabling the internal voltage regulator by holding VREGEN high.
>
> Regards,
> Dan
>
> --- In 6...@yahoogroups.com ,
> Petrescu wrote:
> >
> > Hi,
> > At this stage I think only the chip designer who has an intimate
> > knowledge of
> > internal circuits can explain what you want.
> > Sorry, I do not understand:
> > "mcu now will ONLY work with the external 5VDC
> > applied to these pins"
> > is this behavior after you re-designed the board? Is the internal
> > regulator still
> > enabled or not? (and how did you enabled/disabled)?
> > Regards,
> > IP
> >
> > danazari001 wrote:
> > >
> > > --- In 6...@yahoogroups.com
> ,
> > > Petrescu wrote:
> > > Thanks IP,
> > >
> > > No doubt that I damaged the mcu. What I am hoping that someone
> could
> > > explain is why the mcu now will ONLY work with the external 5VDC
> > > applied to these pins? Although it is somewhat accademic at this
> > > point, I'm currious as to what internal circuitry in particular
> has
> > > been damaged. I am hoping that the behaviour I am seeing in field
> > > can be fully explained by this connection error.
> > >
> > > Thanks,
> > > Dan
> > > >
> > > > Hi,
> > > > The manual states in Appendix: Electrical Characteristics the
> > > followings:
> > > > 1. The device contains an internal voltage regulator to generate
> > > the logic
> > > > and PLL supply out of the I/O supply. The absolute maximum
> ratings
> > > > apply when the device is powered from an external source.
> > > > The maximum allowed: 3V .
> > > > 2. Also: for VDD1 and VDD2:
> > > > Internal power and ground generated by internal regulator. These
> > > also
> > > > allow an external source VDD1, VDD2 to supply the core Vdd /Vss
> > > > voltages and bypass the internal voltage regulator. Nominal
> > > voltage: 2.5V !!
> > > >
> > > > So, it is quite normally to have unexpected behavior.
> > > > Regards,
> > > > IP
> > > >
> > >
> > >
> >

------------------------------------



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