Hi there,
I need a low voltage PLL IC for a design I'm doing. Almost any specs would do as long as the thing is working at 2.5V and has a DIP package for breadboard prototyping (and, of course, is available from mouser/digikey/etc). The best ICs I found require 3V minimum. A frequency-to-voltage converter would also do (that's what I want really) as long as it's in a DIP and works at 2.5V... Couldn't find anything on the web, so asking here.
Best,
- Cesar
what frequency, it could have implications?
0.00001Hz or 1Ghz?martin
- Cesar
3V is easy. The old CD4046s were specified down to there.
I assume you don't also have a -2.5V supply up your sleeve?
Don't you have a higher voltage in something like a RS232 circuit or something?
sounds like you are making only one of these things (not production) in which case you will find that most circuits specified for 3 volts will also work at 2.5.
Mark
Nope. I have a total of 2.7V to work with.
- Cesar
You guess right, it's just one. Maybe I could do that, buy a bunch of ICs and bench test them to get the one that works best at 2.5V. The CD4046, as far as I know, doesn't have a linear VCO so it would not be a linear frequency-to-voltage converter, but I could work around that.
- Cesar
Charge-pump doubler and use a 5V chip?
You could roll your own low voltage VCO from a dual op-amp and an upside-down NPN BJT and use the digital section from an HC4046 for the phase detector.
Best regards, Spehro Pefhany
In the middle of its span the CD4046 was fairly linear. The HC ones differ a lot from maker to maker.
Perhaps. Is there commodity-low-voltage-dip-package-low-power charge pump doubler of choice?
- Cesar
7660 About 50 cents in 100's. Multiple-sourced. Will work at 2.7V if you generate -2.7V and use the + and - rails for your PLL, but that may cause you other problems.
Best regards, Spehro Pefhany
CMOS 555?
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