Engineering Change Order
Friday July 28, 2006
- We received the PPI boards (18) and found an error in the layout. Two nets have been shorted together on all but one connector pair.
That is P3-J3 has no shorted nets but all the rest have net shorts between Vbias2 (Pin 7) and Vbias4 (Pin 6).
Somehow the trace was moved by software directly through the pin.
When the software changes parts it can cause this to occur. The Design Rules Check was not done properly.
- There is too much heating when the normal operating current is applied to the board. The next board design will have each power plane
doubled to lower the board temperature rise.
Meggering the board to adjason high voltage pins yielded >500MOhms at 1000V
10/2/2006 10:32:40 AM
- Modified the layout per Johnny's sugestions. NOTE: Mentor has a SolderMask layer that needs to be worked on to get the
proper Gerbers. I had some pads that had a SolderMask and some that didn't and it caused the Gerbers to have large masks even though
I told it to use the pins instead of the pads to make the soldermask.
- Mentor Graphics Notes: Set the Clearances so the high voltage has more clearance between the plane and the pad.
- Set the thermal on the large pin for more web thickness.
- Plane shapes can be moved to the front or back of other plane shapes.
- Changes to cms-pp1 card.
- Added local ground that picks up chassis ground from mounting screws.
- Added two more ground planes to double the high current connections for 2.5V, 1.25V & Ground.
- Changed Drain 1 connections between Jack and Plug to use 'plane' type connections.
- Changed the monitoring connector from two to one. This works better since the signals do not need
to cross, eliminating vias.
- Layout of Daughter card uses mostly planes. Jumpers allow several different arrangements to determine best grounding
and bypassing scheme.
11/13/2006 3:31:11 PM
- Some problems have developed with the monitoring connector. We changed to a
right-angled connector because the straight connectors interferred with the cables.
It turns out that the right-angled connector hits the bracket of the neighboring board.
- We are trying to find a straight connector to use with a paddle card to allow
visual indicators (lamps/LEDs) and PC interfacing connectors.
- If we keep the height below about 3/4" this should work ok.
Jan. 26, 2007
Changes to the Daughter Cards
- Made the hole size for the pickup loops; 60mils
- Made the hole size for the 12pin SIPs; 24mils
- Lengthened the cards by 1.3mm at each end for assembly purposes.
Changes to the Mother Board
- Fixed plane layers so each thermal has all its spokes.
January 30, 2007
- Changed the Silk Screen to match the Daughter card orientation.
- The current Mother Version is Rev D.1
February 7, 2007
- Changed the 12 pin SIPs hole size again, this time to allow larger pins.
- Plan to use sockets instead of jumpers to lower the Daughter Board profile.
February 12, 2007
- Added surface mount resistors to allow breaking the inner shield and/or
connecting it to the outer shield.
- 0 Ohm resistors will be installed to make the shield-shield connection and
the other resistor will not be installed.
- All capacitors are installed on the Daughter cards. Three jumpers are installed at
J1;2-3, J3;2-J2;2 and J4;2-3