LM1117-33 alternative for lithium battery power source?

Chris,

You are correct, the dropout voltage of the LM1117 is in excess of 0.4V at 800mA.
Are you looking for something that can do up to 800mA? Or do you really need less current than that?
Certainly there are a number of devices that fit your specification, but the options may open up further if you don't actually need the full 800mA.
www.ti.com/.../single-channel-ldo-products.page

You may want to copy and paste the link. Its for the LDO parametric search with something close to your requirements.

Best,
Michael

Hi Michael,

Our main little board needs about 300mA currently but its being modularized in order to support some pluggable sensor modules in future. We are estimating 800mA will be enough for those that we already experiment with.

Thanks for the suggestion page. I found many LDO alternatives there.

But I also found the http:// webench.ti.com, (it is pretty interesting). But now I'm really in doubt. This system recommended some IC that I've never knew about. They are switcher based components, as the TPS6209733, TPS62150A and lot of others.

Most of those step down converters ICs has higher efficiency compared to LDOs. Would they be the best options for battery based circuits instead LDO then ?

Can you recommend any doc or article that would help in choose the best options ?

thanks

Hello Chris,

Sorry for taking a little while to get back.
Absolutely. The webench tool is a really great tool for power design. It gives a lot of suggestions based on our entire portfolio and you can emphasize certain parts of the design from cost to board space to efficiency.

If you are using a battery based circuit in which efficiency is your #1 concern, then certainly a switching regulator would be a good idea. In general, switching regulators are more efficient than LDOs.
There are certainly tradeoffs to Switchers vs. Linear regulators. In general, but not always, LDOs are the cheaper, easier to design, and less noisy solution, but switchers have a huge benefit as far as efficiency is concerned. Fortunately, as you found out, Webench helps to provide solutions in order to make the design process less difficult.

As far as the devices that Webench pointed out to you, I don't know what your manufacturing capabilities are, or how complicated your design is in general, but these two devices are QFN surface mount package components. It is likely you could find a switching regulator that would be able to do exactly what you need but maybe with a less complicated package.

If you are willing to provide more about your design/capabilities (at least as far as what you are comfortable sharing in a public forum), then we might be able to lead you to a better solution.

Best,
Michael

Hi again Michael,

Thanks for the information about the mount package. As you have anticipated the QFN is a very complicated package for our current capabilities.
We would like to use something like SO, SOP, SOT families that are easier to manipulate.
I wasn't able to find a way to select a proper IC using the Webench yet since a column for package it is not presented in the result list that can be exported to excel (and well filtered).
I saw a feature filter by IC Package, but seems that it uses an internal package type reference, at least I couldn't identify anyone :)

The circuit we are prototyping is a kind of sensor data collector that will transmit data via small wifi/RF chips from time to time. It will be powered by 3.7V battery and in some cases it will have a mini solar panel attached as a module that will recharge the battery when possible.
We would thank you If you would direct us to a nice solution.
best, Chris

Great !
many thanks Michael for the help.
We are going to evaluate the datasheet of each item of these lists.

best regards,

Chris