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?
-- -- kensmith@rahul.net forging knowledge
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
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
In the middle of its span the CD4046 was fairly linear. The HC ones differ a lot from maker to maker.
-- -- kensmith@rahul.net forging knowledge
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
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
CMOS 555?
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