Interesting discussion on “low esr”capacitors. Capacitor manufacturers think low esr is in the “eyes of the beholder” In addition a good discussion on X5R/X7R. What does this connotate? Simply this:

X means minimum temperature range -55degC
5 means maximum temperature range +85degC
R means percentage of capacitance change permitted +/- 15%

X means minimum temperature range -55degC
7 means maximum temperature range +125degC
R means percentage of capacitance change permitted +/- 15%

Recommendation is to use X5R/X7R ceramic capacitors at 10uF.

RF PCB design is an important part of the RF product design process. There are a large number of issues the PCB layout person has to bear in mind. Here are a couple of more. (1) Have a solid ground backplane under the RF devices. (2) Use vias to connect ground points to this backplane rather than running thin lines to ground points. Vias should be placed so that the ground trace is really short. ( Long thin traces of course make up an inductance. At high frequencies these can cause problems. (3) Power and ground traces should be wide. A 6 mil trace for example can carry almost 150 mA of current but may still behave oddly. A better choice would be 0.3mm or 0.4mm. More on this subject in other posts.Also try to use a common point supply system. i.e do not daisy chain the supply line. Good luck.

When designing RF power amplifiers with active devices, it is always good to ask what the device is capable of in terms of power gain when everything is matched. i.e If I matched everything what is the maximum gain / performance I could get out of the device. The answer to this question lies in determining the MAG or Maximum Available Gain of the device. Of course, this is a theoretical quantity because it is not possible to get this performance in practice. The MAG then,is the theoretical power gain of a device when its reverse transfer characteristic or admittance/impedance is set to be non existent. In addition, its input and output ports must be conjugate matched with the source and load impedance respectively.Contact Signal Processing Group Inc., for all your RF Power Amplifier questons or needs. Please review RF power amplifier fundamental concepts at http://www.signalpro.biz/rfpa.pdf

Baluns are used quite extensively in electronic design specially in higher frequency or differential circuits. The term “Balun” is an abbreviation for Balanced – Unbalanced. The implication is that a balun converts an unbalanced signal to balanced signals. In some ways Balun operation is not intuitive. An article describing the basics of baluns is presented by Signal Processing Group Inc.’s technical team and can be accessed at http://www.signalpro.biz/free_report_form_balun.html

FM signals are everywhere in the RF/Wireless world. Their resistance to noise and clean reception within their range of operation is exploited by many systems. It is useful sometimes to take a look at the theory behind these signals, at least to the point that an intuitive understanding can become beneficial. A recent paper by Signal Processing Group Inc., has been published that provides a description of the mathematics behind FM signals. A set of simulation results are provided that back up the theory. The paper can be accessed at the SPG website, http://www.signalpro.biz under ” free stuff…”.

Here are a number of reasons why you would want to develop your own ASIC or custom module, analog, RF or mixed signal. (1) You have developed a product using standard off the shelf components. When you did this your suppliers and their salepersons were all over you. Then the salesperson you knew left, or some other event took place. You no longer have the support from your supplier or distributor. Your project is stalled. Or even worse you have your product in the market and your supplier decides to discontinue the product you are using. The product is selling well. At this point you must have your own ASIC or module if you are to be independent of your supplier and their vicissitudes. It may take time and money but if market and product can support it, you must consider your own custom devices. (2) You have developed your product using off the shelf components. It is selling well. If the market is there and your product addresses the market, be assured your product will be copied and released to your market. You then have a number of choices. (A) Sue ’em. (B) Enhance your product. (C) Protect your IP (D) Exit the market. Only (C) is a palatable choice. You can do this by (E) Patents and trademarks (F) Hide your IP using full custom ASICs and modules (G) Enclose your product in a strong coating of some substance that is difficult to penetrate. Of these options we advocate full custom devices, ASICs or modules. You own the IP here, not your suppliers; It is very expensive to reverse engineer an ASIC and with the proper IP protection techniques ( coatings and other processes) it can be very difficult for a copycat to steal the IP. In addition if a portion of the IP is in firmware then this is an additional layer of protection. (3) Your product has been developed to the point of a demo model and it works. The boards and boxes are large and ungainly. You now have to fit it all in a really small area or enclosure. Again this is a really good reason to make your own custom ASIC or module. (4) Your product has been developed to the point of a demo model. It works fine except that it dissipates a lot of power. Perhaps it is a mobile unit and the batteries are running down. Whatever the case, this again is a really good rationale to get your own custom device. Custom devices can be designed to dissipate very little power using good low power techniques. (5) You have developed a product using discrete off the shelf devices. There are a lot of components on the board. This is causing a size increase and a manufacturing headache. Again use of a custom device is strongly recommended. Not only will the size and power come down but the overall product will be more reliable and easy to manufacture. If you want to learn more or develop your custom devices, please contact Signal Processing Group Inc, at http://www.signalpro.biz for a no obligation discussion or quotation. SPG uses state of the art semiconductor, PCB and assembly techniques to provide highly cost effective devices that belong to you.