Click here to register now. Some of the ‘simple switchers’ as well as the dreaded mcA require up to , possibly even uH inductors, which, when running for an output of up to 1Amp, can take up a lot of board space. Back to home page Return to top. Email to friends Share on Facebook – opens in a new window or tab Share on Twitter – opens in a new window or tab Share on Pinterest – opens in a new window or tab. Watch list is full.

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A current output of mA should be possible but it’ll probably be running at mA nominal. I might mock something up and see how it turns out. Fancy ones with integrated switches, simple control loops etc.

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. Your fet spends more l3m485 in “limbo” where it isnt quite on or off, its more like a resisitor. Although, it was under pf, so I was hoping it was be ‘ok’. You can’t use ceramic on the primary cap though, unless as you stated, you use a series lm34885, one of those.


Also, since the output load can ledd as low as 30mA, I wanted my converter to remain relatively efficient at these loads.

I originally picked this chip because I wanted to use a small inductor, that is uH. For additional information, see the Global Shipping Program terms and conditions – opens in a new window or tab This amount includes applicable customs duties, taxes, brokerage and other fees. For a better experience, please enable JavaScript in your browser before proceeding.

By National Semiconductor Corporation.

Anyone here used the LM3485?

Please enter a valid postcode. New PCB, new parts, new design The circuit remained much the same as the evaluation board, with the exception of lmm3485 IRF mosfet as recommendedan inductor with a higher current rating, and a uF NIC neocap I got form a junk laptop motherboard.

The frequency of the controller varied considerably, whenever I moved my hand or the probe, so its very sensitive to noise, and have quite a lot of HF noise on it regardess. Have you computed your switching frequency correctly? A picture of this is attached.

That ESR is going to cause your converter to run at a much higher frequency. There are 1 items available.

LM Led Eval Demo Board Regulator With V Output @A 1pcs | eBay

CafeLogic New Member Mar 13, This item can be sent to United Statesbut the seller has not specified postage options. The AC97 architecture separates the Analog and digital func- tions of the PC Audio system allowing both for system design flexibility and increased performance.


You’re absolutely spot on!! If cafelogic is still around, I would like to discuss this with lde, as he was a great help before. My recommendation to further reduce ripple is to use a secondary output filter. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.

Also the duty cycle was very close to my calculations always a plus eh? I assume these values were experimented with, given the output caps used to get the best efficiency.

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Lm3485 Led Demo Board

Plus I have quite a few 22uH sheilded 1. I came across this article: Perhaps even with a LDO with a 0. According to my ‘rough’ simulations, the ESR doesn’t seem to impact much on the operating frequency, just the output ripple. International postage and import charges paid to Pitney Bowes Inc. Get the item you ordered or get your money back.