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LMR61428: Seeking assistance in picking the right part

Part Number: LMR61428

I'm an old-school developer with mostly linear-regulator experience and am looking for tips on picking the right 'boost' switching regulator for a specific project. It needs to take +5V in, either from a wall-wart or a battery, and give +10V out at 150-200ma. The device it's powering does low-level RF signal analysis in the 500kHz to 2MHz range, so I figured the switcher ought to run somewhere north of 2MHz.  I initially tried a somewhat slower boost switcher with a built-in spread-spectrum 'noise abatement' feature that turned out to create a good deal of hash. This will be a low-production item utilizing a lot of discrete components, so a chip that can be hand-soldered would be appreciated.  The LMR61428 is nice in this regard, but I wonder if its operating frequency can be pushed a bit higher in light of the limited current it needs to supply.  Many thanks in advance for all words of wisdom.

  • Hello James,

    Thank you for reaching out.

    So you need a boost converter that switching frequency higher than 2MHz, right? May I know the reason?

  • Hello, Zack, and thanks for the interest.  The device to be powered is a quite sensitive radio receiver in the 500kHz-2MHz portion of the spectrum.  Attempts to use switching supplies at a frequency within this range, or with harmonics in this range, have generated spurs that interfere with reception.  Thus I assumed that a higher supply operating frequency might be the answer.  I am open to suggestions, and thanks!

  • Hello James,

    Did you already set LMR61428 switching frequency to its maximum 2MHz?

    You can take a look at TPS611781 or TPS61378. These two devices switching frequency could be set to 2.2MHz typically maximum.

  • I've ordered the LMR part, which should arrive soon, and will try it first at its highest switching frequency. The other parts are both QFN packages, which would prove a bit more difficult for hand assembly in small production runs; the end product is mostly thru-hole with only one other SMD part.  I did fine one other boost converter in the VSSOP format that ran at 2.2MHz, I'll look that one up.  Many thanks for your tips!

  • Hi James,

    Let us know if you have further questions.