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Sep 8, 2017 | RF 800 Flux ( cookson brand) - Flux acid calculation and restoration of acid value from 17 to 19 Hi, I need the RF 800 Flux Acid titration procedure and also require EPT of the same to add thinner ( RF 800 additive), i.e we are using the flux rf 800 for our wave soldering process having foam fluxer , after 2 hours we are taking sample from the flux tank and doing the acid number test ,the
Jul 25, 2017 | Is anyone reworking BGA parts with an rf shield on top of the package? Any problems getting it off the board? I am running into an issue in that the shield comes off but the part remains on the board - not because solder has not reached melting but due to BGA solder spheres and rf shield are both
Jan 30, 2017 | Look here: http://arduinobasics.blogspot.com/2014/06/433-mhz-rf-module-with-arduino-tutorial.html
Nov 9, 2016 | Placing RF shields on PCB's. > We are currently running FUJI XPF lines and > receive all of our RF shields in T/R format. > The large shields we use come on a reel of 500, > the small shields come on a reel of 800. both > much more efficient than using trays. I agree. Get them on T&R. Changing out trays
Oct 26, 2016 | Thank you for the info!!
Oct 24, 2016 | Placing RF shields on PCB's. We are currently running FUJI XPF lines and receive all of our RF shields in T/R format. The large shields we use come on a reel of 500, the small shields come on a reel of 800. both much more efficient than using trays.
Feb 12, 2015 | MLCC cracks due to RF shield We have a board that has an RF shield on one side and ceramic capacitors on the other side. The side with the capacitors is reflowed first, then the other side is reflowed. We have been experiencing cracked capacitors in these boards. My guess is that somehow the RF shield is contracting at a
Aug 8, 2011 | We are building a plasma diagnostic to monitor MHD phenomena in tokamak. As part of the development, we need high-voltage, high-power RF capacitors to tune and match an inductive load. This application is similar to a small induction heater, with the following operational parameters: RF Power 2 SMT Design Issues for 2225 Capacitors in High Power RF -4 kW Frequency 50-300 kHz RF Voltage 500-1000 V RF Current 50-100 A Duty Factor would be 10 second pulses 10 minutes apart with continuous operation at lower power for testing and calibration. We need to build two digitally adjustable capacitors (0.6-5.0 uF and 0.1-9.0 uF) out of smaller surface
Jun 3, 2011 | SMT RF shield Dewetting & Misalignment Hi there, I have questions regarding on SMT RF Shield dewetting & misalignment issue.. Q1) How to identify on good or bad RF shield that could contribute to dewetting? Q2) What counter measure that must be taken when facing dewetting issue? Q3) What counter measure that must be taken when
Mar 4, 2011 | First, I would inspect for lack of solder bridges from the center slug to the outside leads. I would then look for evidence that the solder paste has reflowed beneath the component, without leaving too much void percentage. Typically we allow up to 25% voiding for these parts, in RF applications I have seen a push towards a much lower void percentage. Controlling the voiding is related to the paste deposition, percentage of coverage of the center pad, and to the pattern by which the paste is deposited on the PCB. For example, a square will leave larger void % than a pattern of dots
Jan 20, 2011 | Dear Industry experts, We have just developed a leadless, fluxless solder that can join various metals ) Al, Cu, brass, Steel, stainless and Titanium) and Ceramics ( Ruby, Quartz, Sapphires, glass, TiO2, etc) We intend to explore electronics and RF applications for Al ( external radar antenna
Aug 31, 2010 | Hello all, Can anyone know what influence has on RF/HF components when using PCB with OSP coating? We are now manufacturing our RF components on PCB with ENIG coating ,and want to use OSP instead. By the way:If anyone can send me an article on this subject it will be great. Thanks!
Jan 4, 2010 | ? if not no need to bake pre hand solder. 3) The rules we follow for baking pre-test is if the parts are susceptible to moisture entrapment and voltage is applied we bake out to remove any water which could create a short or cause impedance issues during test (we have found moisture to be an issue in RF applications).
Oct 30, 2008 | For most applications, a nice square [or rectangle] pad works just fine. Assemblers ship boat loads of boards with these every day. It's reasonable for tight decoupling capacitor requirement applications to use round or radiused pads for components at BGA pads and via. For some applications they thry to implement RF designs. So, why not check-out the design guidelines for the BGA used on the board to understand better if your designer is on-track or in need of an alignment?
Oct 19, 2008 | RF board not soldered We are having some issues with a RF PCB aprox 1" x 1". The pads are in the bottom of the PCB and it goes on the Top side of the mother board the pads of the RF board are like a BGA (square pads)and we have troubles to make the proper welding in the pads of the RF board with the pads of the mother
Sep 30, 2008 | -clean flux aimed at RF applications say, "This material has been utilized on various assemblies with RF designs without cleaning; however, the compatibility of flux residues on RF assemblies is strongly dependent upon circuitry design." The tech sheet from your AIM NC254 No-clean solder paste gives Residues from different no-clean fluxes produce different levels of variation in RF circuits. Some no-clean fluxes work fine. Following this, a no-clean flux can produce different levels of variation in RF circuits depending on the process setup. Often the data sheets for solder paste with no no indication that it can spell RF, even if you spotted it the "R".
Apr 8, 2008 | Duno. Which LPI Solder Mask are you using?
Mar 3, 2008 | I have a project to evaluate solderability of various metals or plated finish. I'd like to tap in to get some advise. The project is to evaluate solderability of various metals or plated finishes for RF shield application with reflow. Due to the high corrosion resistance, Cu-Ni alloy
Nov 8, 2007 | No. Leave your desk. Go get your hands dirty.
Nov 5, 2007 | RF BOARD + SOLDER PASTE TYPE PROBLEM As unlikely that this may be, if the RF circuit is sensitive enough, and the minor change in alloy is the only thing that changed, this MAY be the cause. The circuit was probably tuned to Sn63/Pb37. The reason I'm not surprised? I once had a customer ask me to increase solder volume on perfectly good solder fillets on MELF components. The reason? RF. Anyway I did what he asked. I overprinted the pad by a mil on each side, and it worked. He got his soldering attenaes. Good luck!
Nov 4, 2007 | RF BOARD + SOLDER PASTE TYPE PROBLEM we are manufacturing some rf boards that works on a high frequency margins now our boards doesn't pass in impedance test and we concluded that the problem might cause by the solder paste that we are using . our solder alloy is sn62/pb36/ag2 and we think that it might be form the AG2 that is used
May 25, 2007 | High Freq. RF grade ceramic filled PTFE PCB material Soldering PTFE boards * Exposure to the high temperatures needed for solder reflow poses no problem of loss of peel strength since the exposure times are relatively short. * There are many different types of PTFE based products that may perform differently in multilayer applications. Generally
Mar 12, 2007 | RF Shields You should tell your customer that they're very nice people, but the purpose of RF shields is reduce RF emissions, not to be a air or gas tight enclosure. The requirements of hermeticity are wholly different than those of RF shielding. Do they want a hermetic, RF shield?
Mar 12, 2007 | I suggested that tothe customer but they require an hermetic seal?
Feb 3, 2007 | Conductive Adhesives in a Digital RF application Anyone out there in the Cyber SMT world have success/experience utilizing conductive adhesives as a substitute for typical eutectic alloys? Application is for a Single sided SMT Process. With a reliability life span of 8 hours. Forum feedback could save me bundles in typical start up costs
Jan 27, 2007 | Hi, Why is no-clean and rf not considered to be a good process? Dave
Aug 11, 2006 | Hi, We have a issue with current leakage between pins on an SSOP 28 in a low frequency RF application and there is a suspicion that it is being caused by something in the flux residue. We have had the bad boards analyzed and a 'high' Chloride level was found. Does anyone have some data on what
Feb 27, 2006 | contamination caused by an eventual bias in some process parameters, or maybe accumulated contaminations in the solder pot. * I know that ROSE testers are commonly used in military, high quality and RF PCB assembling. Some times this is done in conjunction with other methods such as SIR and ion chromatography . Our application is just COMMERCIAL QUALITY TV CHASSIS, and what I�m wondering about is: 1- Are these tests used for this range of applications? 2- Do TV applications (being a consumer domestic product) tolerate some ion residue in such a way that we can disregard ion tests? 3- Should we worry about ion contamination (for our application) if we use a good machine using a spray fluxer, a good flux, and process parameters satisfying flux requirements? I hope I�ve made it clear, and I hope I�ll get your help that I�ll appreciate much. Regards,
Sep 21, 2005 | go beat the designer over the head until he separates the pads or uses solder mask.
Sep 20, 2005 | Defect reduction on RF design 2251 - Design Guide for the Packaging of High Speed Electronic Circuits 2252 - Design Guide for RF/Microwave Circuit Boards
Sep 19, 2005 | Defect reduction on RF design Good Morning Everyone, We have a customer that produces RF based assemblies. We are building several board types for them, all of which have an "RF" area of the PCB. This RF area does not have any mask to define pads. There are also several issues with components sharing pads, unequal thermal mass
Aug 31, 2005 | im running some tests at the moment for hand soldering using a no residue water based flux from MBO,
Aug 30, 2005 | No-Clean flux residue and RF application Dear Ing, Have you analyzed why some RF device aren't operational after washing? An assumption is that failures are related to the ultrasonic energy applied. Other possibilities are for poor rinsing, poor drying, inadequate washing on those failed devices, etc. The use of an ultrasonic cleaner
Aug 30, 2005 | Yes a No-Residue solder paste exist. email me for more info Pat
Aug 30, 2005 | The answer for us at my previous employer was water soluble flux. Wash the board, no residue. If you
Aug 30, 2005 | No-Clean flux residue and RF application Hi, I curently have an interesting challenge. But I don't have all the knowledge to solve it. One of our boards is used in RF applications. We noticed that the No-Clean flux residue makes interferences in the RF signal. Removing the flux residue solve the problem. But washing the board in an ultrsonic cleaner gives us other problems. Sometimes some RF device aren't operational after washing. Does anyone know a solution for this kind of application? What the cell phones company does for that? Does exist a solder paste with no residue? Thanks to all for your collaboration.
Aug 10, 2005 | The propensity for flux residues to cause shorts can be increased in humid environments where water molecules hydrate the surfaces. At high frequencies, electrons travel on the surface of conductors/insulators, increasing the likelihood of shorts in RF applications. Steve Stach Austin American
Aug 10, 2005 | to clean than low res. * Other RF applications have avoided cleaning of low res fluxes. Flux suppliers say things like: -- This material has been utilized on various assemblies with RF designs without cleaning; however, the compatibility of flux residues on RF assemblies is strongly dependent upon Comments are: * Sounds like it's necessary to clean "heareous F381, F352 no clean solder paste" in your application. Consider a paste that may be better suited to your application. * If you're cleaning "low residue flux", consider using an organic acid flux? OA fluxes are much easier and cheaper circuitry design. -- Post-process residues may remain on the PCB in RF designs without cleaning. Above 2GHz cleaning maybe required. -- Post-process residues may remain on the PWB in RF designs up to 10 gigahertz without cleaning. Above 10 gigahertz cleaning is recommended.
Feb 9, 2005 | RFMD RF2114 Power Amp replacement Did you ever find a replacement part for the RF2114? I am currently looking for a replacement as well.
Feb 10, 2004 | the solder mask smaller (preferred) on the ground plane side to match the size of the pad on the other end, or make the apertures bigger for the ground plane side to even out the surface tension. Neither of these should hamper the rf function much, if at all. For the non-soldering ground plane, it may be that it is a combination of requiring so much heat and using too much ramp to get there. The profile recommended by the paste mfgr is a good starting point, but you may have to adjust it as needed, especially in this application. I have had to make the reflow zone hotter and longer in duration in many case
Feb 1, 2004 | % closed loop) Microwave and RF applications (typically) are excluded from no-clean flux types; As-well-as Hi-reliability assemblies. Save yourself the trouble. It's easier to implement an OA flux and wash process than semi-aqueous was process. Do you currently omega-meter, ionograph or SIR test?
Nov 27, 2003 | Has anyone in this forum experience the can soldering defect? The can component is supposed to be placed on top of a group of RF components to protect the frequency from escaping and interfere with the adjacent RF component. After the reflow process, there are opens which can be seen by the naked
Nov 11, 2003 | Solder Paste & RF products Folks, has anyone heard fo any problems with RF cards related to solder paste selection. Currently runnign with std SnPb paste but want to move to 2% silver paste. Was asked if this could cause any issues in term's of RF capability or interferance to the card. Running RF cards before on 2% silver
Apr 23, 2003 | IPC-2252 Design guideline for RF/Microwave PCBs Now I urgently need the standard of IPC-2252 Design guideline for RF/Microwave PCBs, Who can help me? By the way,who can recommend some DFM experts on RF PCB design?look forward to your responding.thank you! Bob
Mar 3, 2003 | I've never heard of a customer saying just 'we want decoupling caps'. Very interesting. In RF applications - frequencies 50MHz up into several GHz, the location of where they are put is just as important as what the value is. Decoupling caps are part of the circuitry and planned very carefully for both value and location. Spec'ing decoupling caps is not like saying 'I want you to use FR4'. Definition of coupling and decoupling caps, for interest sake. Caps pass oscillations, but block DC. So a coupling cap is usually put in the signal path, allowing the RF signal pass through to the next point in the circuit, while blocking the DC. A decoupling cap does the same thing but for the opposite purpose - it passes oscillations but blocks DC, so it will be used as an RF ground in this case. It will be put where you don't want oscillations, like a power line, and be connected to ground
Feb 14, 2003 | DAVE- The way we got around it was simple- Our Mole for profiling is RF and the cell phones would interupt the data transfer so we nixed all cell use. Also, our BTU oven was in constant RF communication with our KIC and so cells were band from the floor. hopefully you have a RF mole. Cal
Feb 6, 2003 | Actually, the most common reason I have seen vias in pads is for grounds in RF applications where the frequencies are high enough that you need a ground RIGHT THERE!... not .1" away. Vias and traces have RF properties of capacitance and inductance, so running a short trace to a ground via can have
Jul 30, 2002 | Voids in grounding pad of RF PCB Hi Anyone has experience in manufacturing RF PCB and encounter voids on the grounding pads? The grounding pad is covered by the a big component. Question is does voids in the solder joint affect the RF operation?
Apr 15, 2002 | Points are: * Seminal study is: "Evaluation of Low Residue Soldering for Military and Commercial Applications: A Report from the Low Residue Soldering Task Force," published by Sandia National Labs in June 1995. Look here http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=19507 ) laments on the difficulty of using NC flux in RF circuits. * Other areas of concern about circuit performance are: conformal coating
Apr 15, 2002 | Solder paste for RF boards Problems using NC in RF circuits are peculiar. Depending on the situation [ie, circuit layout, frequency of use, processes used, materials, and what not], a particular NC flux may not work with a RF circuit. Various NC fluxes leave different levels of crud on the board that can affect RF clean. * Asking your solder paste / flux supplier for recommendations that suit your application.