Circuit Break - A MacroFab Podcast

MEP EP#268: Avoid The ExtremesFan controller for Jeep Brushless fan temperature controller Nothing fancy but the “override” signal is ground triggered! Will have to invert the A/C compressor signal with a relay Controlling PCB cost What are the knobs that can be turned to adjust the cost of the PCB itself? The easy ones Size (not necessarily rectangle) Panelization Base material TG ratings - The glass transition temperature FR4 Trace/Space Minimum hole size Mask Color Surface finish Copper weight Not as easy ones Vias Tented Plugged Blind Buried Digikey’s Latest Innovation Information printed on the backside of cut tape 8mm tape

17 Mar 20211h 3min

MEP EP#267: Honey, I Shrunk The PartsTradeoffs on component sizes "World's Smallest" Claims Can Come With Trade-Offs Design and Production considerations when going small Different PCB Design Rule Checks PCB pricing Via in Pad Escaping Components Silkscreen Part placements Assembly documents Tooling Paste Jetter Stencil coatings STICKERS/Labels for products Find out what label printers your CM is using Consumable items Label Material Location! Location! Location! Printing Instructions and Information Databases Low frequency Network analyzer Perhaps I am looking for the wrong thing but I can’t seem to find what I want 1hz to 100khz range Can always do it manually but damn is it slow Tsunami - this is *almost* what I want but not really good enough I want to design one but no…..

10 Mar 202155min

MEP EP#266: The ExpertDesign for Manufacturing – Beyond the Digital Domain Webinar that Chris Church (Co-Founder of MacroFab) will be co-hosting with Edwin Robledo of AutoDesk. Building a Program and Testing procedure for your first production run Take lots of pictures Keep it up to date and version controlled Hand off the procedure to a colleague and have them run through it Work with your CM MacroFab works closely to help flesh out procedures and fixture designs What is you acceptable fall out from production This is where scaling up production runs can help iron out QA procedures for your product Find tolerancing issues with components Keep in mind your target pricing Elements of a good test procedure - THINGS TO KEEP IN MIND It is almost impossible to have too much information in your test procedure - within reason. Remember - Your CM can always distill your information down to something less than what you provide Typically they have one “expert” who knows everything and multiple operators who execute the tasks. You don’t know when your documentation is needed so be thorough Things to include in the documentation - preferably at the top Product/assembly name Test procedure Rev List of board revisions that this procedure applies to Map or image of terms or items List of ALL software required Do not assume that your CM has anything If software version is important make sure this is called out List of ALL files required Be explicit with the names Do not be shy with file structure Be consistent If you call a board X then always call it X Test procedure Meat and potatoes List of required equipment What can be expected of a CM to have? Be granular here. All the way down to cables Do not be afraid to call out amazon links to required items Avoid parallel anything - Sequential steps are the best Always have criteria and be reasonable! consider how the operator will approach your target and adjust accordingly! Failures - Let the operator know what to do with a failure If anything is to be marked or saved be explicit how and where to do it. If there is a sticker or label to be applied show a picture where you want it to go.

3 Mar 202154min

MEP EP#265: NuFuel and Gas ClassicResealing 12oz cans? FAIL! Worked till can shaken a bunch Improvements Working on finding a softer sealing surface Currently using a Shore 55A neoprene rubber sheet Increase seal pressure on can Carmakers wake up to new pecking order as chip crunch intensifies Follow up from last week's discussion on Auto industry shutting down production due to lack of electrical components. Both automakers and chip manufactures are pointing fingers Chip makers point at the auto industry in that they are quick to cut production and cancel orders when car sales slump Auto industry where used to being the center of attention for chip and electrical component manufacturers The industry spends around $40 billion dollars a year on chips By Comparison, Apple spends more on chips just to make iPhones! Chips used in Auto tend to be more basic products and older micro controllers, Something that chip fabs do not really want to invest more production into Chip Fabs are prioritizing higher margin, leading edge components OnSemi plans to be back on schedule by 3rd Quarter Eagle EDA Tool Designing parts from the bottom! Starting a small business to sell hardware? Tips for Parker? This will be covered next week DipTrace - PCB teardrops Benefits Stronger pad adhesion making for better reworkability Prevents acid traps at sharp corners where traces meet a pad This really is not an issue anymore Inspect your board and run your DRC Potentially make shorted pins appear worse Interesting tombstone issue Coolio opamp - TLV915x Pricing TLV9152 $0.354 in qty TLV9154 $0.525 in qty Offset 125uV typ 780uV max across temp Input bias and input offset 10pA 20V power 750uA max across temperature supply current per channel Rail to rail 2k load 250mV from rail with 16V power Drops to a fe mV with lower power Cyberpunk is Real! Porsche's e-fuel is like a real life CHOOH2

24 Feb 20211h 12min

MEP EP#264: Electronic Wear ItemsTesla Recalls Cars With EMMC Failures, Calls Part A ‘Wear Item’ Wear items on cars are designed to be “easily” serviced Is this just a cop out to avoid warranty issues and recall problems? If the EMMC is a wear item it should have a recommended service interval but it does not Derek Fronek from the slack channel: “So it finally happened.... after all these years of using SD cards on pi's ive never had an SD card fail on me, until today.......” Resealing 12oz cans? 3D printed a sealing cap that screws onto a Yeti can insulator Testing it out over the weekend GM to extend vehicle plant shutdowns to more than a month The chip shortages we have been talking about? GM expects it to get worse. Ford cutting Pick Up Truck production! Shortage could lower Ford’s earnings in 2021 by $2.5 Billion Suppliers are saying by mid June they will be caught up PinoTaur REV 4 Prototype ordered Relay part number: G2RG-2A-X DC12 Changing current sense IC to a higher rated one for the 50V DC line Added a second RGB channel for the serial LEDs Digi-Key Elimination Search Talked about this on Episode 260: A Couple Months Ago Use a ~ in the “search within results” box to eliminate whatever you like from your search Coolio Opamp TLV915x $0.512 in 1k qty from TI 125uV offset 16V Rail to rail Parallax Prop 2 exists! Parker has a development board now

18 Feb 202151min

MEP EP#263: Hoarders EditionChris Carter Owner of Mercury inc, a design consulting firm with expertise in electrical mechanical software and firmware development Was last seen on MEP episode 244 Comic Con for Engineers DFM For Safety As in Supply Chain Safety Difference in projects Project specific information Based on price and quantity breaks for components Multiple Vendors Vendor accessibility (location location location) Alternate sources Communications between contract manufacturer Too many cooks in the kitchen

10 Feb 20211h 5min

MEP EP#262: Flex PCB PrimersParker Robert Feranec Published a video about what to consider when selecting chips for your new board design. Don’t want to steal Robert's content so go check him out. Hardware design and PCB Layout online course Comprehensive Power Supply System Designs for Harsh Automotive Environments Consume Minimal Space, Preserve Battery Charge, Feature Low EMI Analog engineer Bin Wu and previous Linear Tech engineer Zhongming Ye writing an application note with linear tech devices. ‘An Ideal Diode Satisfies Automotive Immunity Norms’ LT8672 Active rectifier controller Why is all this needed? Car power is dirty Load dumps Cold cranking Pulses ISO 7632-2 is a negative spike whose peak voltage exceeds −220 V! Reverse Polarity AC Ripple Stephen Wurth Elektronik on Flex PCBs Basically Polyimide foil with deposited copper 3 ways to create a system (from page 2) Heterogeneous Homogeneous Partial Homogeneous Full flex and Semiflex Much Much easier way to create a 3d system design Added benefit of having a full panelized system Can test a full panel of designs all at once Test points can technically be on the flex Break and make Take the rails off of the PCB Flex-rigid boards Can be bonded to external layers Can be internal Can be rigid on one side or both Can be multiple layers Layout and routing Create a new layer in your EDA tool to define the Flex portion No vias in flex portion Use teardrops for added rigidity Use wider tracks where possible for added strength Do not change width in bend area Distribute conductors evenly Documentation Do it... Do it a lot In addition to the PCB gerber or ODB++ files include drawings A fab drawing that defines the flex pcb is very helpful

3 Feb 202143min

MEP EP#261: Critical Path ComponentsParker What can you do to help alleviate component shortages and lead times in your design Last week we talked about automotive component shortages Passive components Most passives it is easy to find substitutes Check your specifications Components that have extraordinary specs for there package size Active components Diversify what you can Discretes Diodes Mosfets Integrated Components Different packages or packaging Connectors Different plating options possible? Other manufactures making similar or compatible parts Stephen Searching for components kind of sucks sometimes. Another Quick idea for making this easier Anything that is a complement Connectors Transistors Guessed BCP54 - BCP52 PCB Crosstalk Video by Robert Feranec with Eric Bogatin What causes PCB crosstalk? Capacitive coupling Inductive coupling Effects of pcb crosstalk How do we mitigate pcb crosstalk? One other form of “crosstalk” that really isn't crosstalk Poor filtering and PSRR “Feedforward” current Not really something that shows up often...

28 Jan 202155min