The higher the frequency, the more important this is. If you are using too large a PFET, that can be a problem. Learn more – opens in a new window or tab International postage paid to Pitney Bowes Inc. Plus, with the replies from this thread it helped me gain a much better understanding of converters, MOSFET’s, power electroics, and even filled in many gaps in my analogue knowledge. Please enter a valid postcode.

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Judging by the 22uH inductor, I would off-the-cuff guess this circuit was designed to operate around k.

Anyone here used the LM? | Electronics Forum (Circuits, Projects and Microcontrollers)

Original price EUR For additional information, see the Lde Shipping Program terms and conditions – opens in a new window or tab This amount includes applicable customs duties, taxes, ln3485 and other fees.

Learn more – opens in a new window or tab Any international postage is paid in part to Pitney Bowes Inc. This lm34885 uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.

Plus I have quite a few 22uH sheilded 1. Graphic LCD – Aff. Articles Top Articles Search resources. So, I guess the main problem with my setup is the FET? Simple deep searching metal detector circuit. The feed forward cap also ranges from p to 1nF. According to my ‘rough’ simulations, the ESR doesn’t seem to impact much on the operating frequency, just the output ripple.


I’m afraid I was assuming that the value simply determined output ripple rather than be a part lmm3485 the hysteric operation as in this case. Hey folks, don’t know if anyone who replied here are still active members, I hope so! Any example circuits apart from those from national?

They are basing their charts on a 80 millohm capaciter. This chain feature re- quires only a single data stream to the controller. Also, the output capacitor must have a well defined esr.

Watch list is full. No additional import charges at delivery! Ill post a pic, this is a boost converter for a pressure sensor I designed.

Once its functional, and running cool, then comes reducing board space. My PFET always stays cool, even at 2.

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The whole thing is difficult to quantify and the only reliable you can determine switching times in your circuit is with an oscilloscope. You must log in or register to reply here. Gillyme9times New Member Jul 13, If you ever wondered how you motherboard can deliver Amps to your power hungry Core 2 Quad with those tiny caps, they use what is called a multiphase buck regulator.


Sign in to check out Check out as a guest. The frequency of the controller varied considerably, whenever I llm3485 my hand or the probe, so its very sensitive to noise, and have quite a lot of HF noise on it regardess. I thought this was high enough as to not require a series resistor for correct hysteric operation. This amount is subject to change until you make payment. By National Semiconductor Corporation.

Its bugging me somethign rotton Visit my eBay store. I realise there is the MCA, as well as national’s ‘simple switchers’, ln3485 I have these and want to get them working for me Essentially, I’m after a small footprint replacement for a standard LM linear regulator for medium current applications.