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Sunday, December 17, 2017

New Copper Wrap Requirements in IPC-6012D-AM1, Starting in 2018

New  Copper Wrap Requirements in IPC-6012D-AM1, Starting January 1, 2018

Criteria for class 3 copper wrap plating effective January 1, 2018 for new designs

IPC released in October 2017, IPC-6012D-AM1, Qualification and Performance Specification for Rigid Printed Boards. This amendment brought to light the new acceptance criteria for copper wrap plating on class 3 products. The IPC D-33a task group provided an effective date of January 1, 2018 for new designs using the criteria set aside in Amendment 1. Legacy designs would continue to use the criteria established in the original standard IPC-6012D from September 2015.


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Sunday, November 26, 2017

Calculating Voltage Drops - Saturn PCB Toolkit

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Example:

Start by getting the Conductor's DC Resistance

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0.04445 Ohms in the above example


Select the Ohm's Law tab, Solve for Volts, enter the trace DC resistance and current.

Then select Solve.

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That's it !

Tuesday, October 10, 2017

Landless Vias

You may be surprised to know that HP Test equipment has used landless vias (no annular rings) for several years.

HP’s studies show the landless vias can be more reliable than vias with pads.

Benefits include higher routing density (more traces per layer) which may reduce the total number of layers required in the PCB stackup.

Every layer pair in the stackup is approximately a 20% cost adder.

The trick is to find the fabricator that knows the process for plating via barrels with no annular rings.  

























Thursday, August 31, 2017

Saturday, July 1, 2017

Lumped / Distributed Line Length Calculator

Updated Feb 16, 2020

Digital     1/4  
RF Ckts  1/12
Analog    1/16
Stitching Vias 1/20









































Inner layer example calculation where Risetime = 5nSec

click on image to view



Lumped / Distributed Line Length Boundary ~ 7.27 Inches

Outer layer example calculation where Risetime = 5nSec



Note Effective ER (2.55) is lower on outer layers

That's it !

Wednesday, June 21, 2017

ESD Protection Layout Guide

Texas Instruments Application Report 

SLVA680 - Feb 2015

http://www.ti.com/lit/an/slva680/slva680.pdf

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Electrolytic Caps - Polarity Markings

IPC-7351B Component Zero Orientation AppNote

Click images to view


Source: Mentor Graphics AppNote 10831
















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Friday, May 19, 2017

Paste Stencil - Area Ratio Calculator

Area Ratio Calculator: Beam On

 Area Ratio Calculator
















To achieve proper paste release from the stencil, an aperture's aspect ratio should be >1.5, and the area ratio should be >0.66. When the stencil separates from the board, paste release encounters a competing process; solder paste will either transfer to the pad on the board or stick to the aperture side walls. When the pad area is greater than 0.66 of the inside aperture wall area, a complete paste transfer should occur. Please see the below calculator which you can use to determine pad size for your aperture, and foil thickness of the stencil.





















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Thursday, May 18, 2017

Thursday, May 11, 2017

HDI (High Density Interconnect PCBs) - TTM Technologies, Inc.

"Advanced Capabilities: Microvias

A microvia maintains a laser drilled diameter of typically 0.006" (150µm), 0.005" (125µm), or 0.004" (100µm), which are optically aligned and require a pad diameter typically 0.012" (300µm), 0.010" (250µm), or 0.008" (200µm), allowing additional routing density. Microvias can be via-in-pad, offset, staggered or stacked, non-conductive filled and copper plated over the top or solid copper filled or plated. Microvias add value when routing out of fine pitch BGAs such as 0.8 mm pitch devices and below.
Additionally, microvias add value when routing out of a 0.5 mm pitch device where staggered microvias can be used, however, routing micro-BGAs such as 0.4 mm, 0.3 mm, or 0.25 mm pitch device, requires the use of Stacked MicroVias® using an inverted pyramid routing technique.
TTM maintains years of experience with HDI products and was a pioneer of second generation microvias or Stacked MicroVias (SMV®). SMV® Technology offers solid copper stacked microvias providing rout-out solutions for micro BGAs.
TTM developed and now offers an entire family of microvia technology solutions for your next generation products."

Source: HDI (High Density Interconnect PCBs) - TTM Technologies, Inc.:



















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BGA 800 PAD 0.4 mm pitch - FEDEVEL Forums

"This is the manufacturer we normally use at our company:
http://www.stevenagecircuits.co.uk/engineers

Different things need to be considering when working with such small clearances:

- Copper to copper clearance - probably the most obvious one. The value might need to be more on plated layers (top and bottom for example, but could be some others as well), since because of the plating they cannot achieve such a good accuracy. The values for plated and non-plated layers are normally given by the PCB manufacturer. It also depends which technology you want to use, for better technologies you are getting better values, but you pay more. With Stevenage we can get down to 50 um for none-plated layers and 76 um for plated layers using the most advanced technology.

- Track thickness - again it goes down to 50/76 um with the best technology offered by Stevenage.

- Minimum mechanical hole - concerns TH vias. Goes down to 0.15 mm. It is very important to know that this is the size of the drill piece they use to drill the holes. If in Altium you have 0.2 mm via hole for example, that is the finished hole diameter after plating. Because of the plating thickness, they always need to use a bigger drill size, so there is enough space for the plating and after the plating you will get a finished hole diameter of 0.2 mm as desired. With one of my boards they needed to use 0.3 mm drills for the 0.2 mm via holes. We were fortunate that this was not a problem with the particular board, but it could be in many cases. So always keep that in mind when you set up rules and work out clearances.

- Minimum laser hole - concerns micro vias. Goes down to 60 um. The aspect ratio (depth to diameter) is quite small with micro vias (as Robert explains well in the Advanced Layout course) and that should be always considered. With Stevenage it can be up to 1.3:1. That means that if you have a micro via with a hole diameter of 0.1 mm it can go a maximum of 0.13 mm in depth. That will normally be just the distance between two layers next to each other. If you decide to go with a very small micro vias (0.06 mm lets say) you might found that they can't be long enough to connect two layers in your stack.

- Minimum micro via pad - goes down to 188 um for the surface layer (top/bottom) and 138 um for inner layers. Using vias in pads helps to gain additional space as well, to do some routing on the top layer, but requires a more advanced technology and might lead sometimes to problems with successful soldering of the BGA.

- Minimum solder mask expansion/Minimum solder mask sliver. If you use too small of a value for the expansion, you risk some pads to be partially covered by solder mask after manufacturing. If you use too small of a value for the solder mask sliver, you risk getting shorts between pads. To prevent such problems, I found it is a good practice for example to cover (tent) vias which are underneath a BGA. With Stevenage the minimum expansion you can have is 25 um and the minimum sliver is 76 um.

Again all of that should be checked with the particular manufacturer prior to starting the design, since as Robert explained you might easily find that they either can't manufacturer the board or the yield could be pretty low."


Source: BGA 800 PAD 0.4 mm pitch - FEDEVEL Forums:

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OrCAD Capture Cloud | OrCAD

OrCAD Capture Cloud | OrCAD:

Free OrCAD Schematic Capture - Cloud Based

Sponsored by Arrow

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Thursday, March 16, 2017

GC-Prevue - Align Layers

GC-Prevue is my favorite Gerber Viewer.

To align layers select a pad or feature that exists on both layers.  Select all objects on the layer that is to be moved.  Place the cursor near a pad, press S (select) key to center on the pad then press the Z (zero) key.  Press space bar to move (unlock) crosshair.  On the other layer place the cursor near the same pad, select S key, then O (offset) key, then OK to align the layers.   

select edit mode (press e key) for the layer the is to be move


Thats it !

Wednesday, March 8, 2017

PCB Trace Voltage Drop Calculation

Get trace resistance from Saturn PCB Calculator - Conductor Properties





















Calculate Trace Voltage Drop using Ohms Law























That's it !

Wednesday, February 22, 2017

Transceiver Link Design Guidelines for High-Gbps Data Rate Transmission - Altera

Altera AppNote AN672 was recently updated. This app note is perfect for anyone who is on the high speed learning curve.

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Sunday, February 19, 2017

How to 'Exclude' parts in HyperLynx | Mentor Graphics Communities

How to 'Exclude' parts in HyperLynx | Mentor Graphics Communities:

An unanswered question.


There are resistors in this design that can be fitted or not fitted to determine the signal paths. 


To accurately simulate this design Hyperlynx would need to analyze the signal path and stub lengths based on which parts are installed and not fitted.


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The question is how would you remove the stubs and paths from within Hyperlynx to simulate the design as though the parts were not fitted (removing the stub paths).


Comments welcome and appreciated !

Monday, February 13, 2017

Via fence - Thumb Rules

Thumb rules:

Stitching Vias for RF should be spaced at lamba/20, where lamba equals the wavelength of the highest frequency of interest.

For striplines, "a rule of thumb is to place the fences at least four times the trace to ground plane distance away from the line being guarded"


Source: Via fence - Wikipedia:

Wednesday, January 25, 2017

Thermal Solutions




















Thermal Vias – A Packaging Engineer's Best Friend















Source: Electronics Cooling

Thermal Conductivity of Metals

Aluminum (w/m K) > 200

Copper  (w/m K) > 386




Carbon Steel is a poor thermal conductor, (w/m K)  ~ 30 to 50.

For heat sinks copper and aluminum are obvious choices due to their superior thermal properties and cost. 



Click on image to view
 Cooler Guys

EnzoTech

CNB-S1L


  • Multiple push pin locations for universal mounting on various board assembly (hole to hole distance: 53mm to 59mm)
  • Formed of pure copper to enhance thermal conductivity.
  • Excellent surface flatness minimizes the interface between heat source and heat sink.

EnzoTech SLF-30(mm)







Digi-Key

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TTM's Thermal Management Solutions


TTM offers a wide range of Thermal Management types to include Via Farms, Heatsinks/Pallets, Heatsink Coins, Embedded Coins, E-Coin, Press Fit Coin (PFC), Metal In-lay and Solder or Adhesive attach.





























Source:  TTM's Thermal Management Solutions

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