buck stepdown chips

[Jamie Morken]

Hi,

I am looking for some high frequency (1MHz+) step down buck switcher
chips that can handle an input voltage of at least 7.4V and at least
500mA output current. The Texas Instruments TPS623xx 500mA/3MHz
switchers are perfect but they are only rated at 6Volts input max! I am
sure they could take 7.4V but I would rather not risk this I need to
generate 5V, 3.3V and several other lower voltages from the 7.4V (two
lithium batteries in series). This is a portable application, so power
is an issue or I would just use a linear regulator to generate 6V from
the 7.4V input.

cheers,
Jamie Morken

 

[Anders F]

"Jamie Morken" <jmorken@shaw.ca> wrote in message
news:exTod.15315$l65.3138@clgrps13...

Hi,
I am looking for some high frequency (1MHz+) step down buck switcher

So you're space constrained? Lower switch freq=higher efficiency...

chips that can handle an input voltage of at least 7.4V and at least
500mA output current.

Lots of them around! Check National, Maxim, Semtec etc...

/A

 

[John Devereux]

Jamie Morken <jmorken@shaw.ca> writes:

Hi,

I am looking for some high frequency (1MHz+) step down buck switcher
chips that can handle an input voltage of at least 7.4V and at least
500mA output current. The Texas Instruments TPS623xx 500mA/3MHz
switchers are perfect but they are only rated at 6Volts input max! I
am sure they could take 7.4V but I would rather not risk this I
need to generate 5V, 3.3V and several other lower voltages from the
7.4V (two lithium batteries in series). This is a portable
application, so power is an issue or I would just use a linear
regulator to generate 6V from the 7.4V input.

Did you look at the TPS62050? It accepts up to 10V input and is pretty
efficient. It runs at 850kHz usually, which is a bit under your
1MHz. Although it would seem you can synchronize it to an external
signal up to 1.2MHz so it might still be OK. I have used them without
problems (although the packaging is quite small and they can be
difficult to get sometimes).

--

John Devereux