My master clock is being generated by a device running on a 3.3V supply. I need this signal to clock an AVR running at 5V. Can I connect it directly or will some level translation be needed? What level translators will work at 20MHz? Suggestions please. :? And before you ask, I can't do it the other way round; the master clock is ultra low jitter type, supposedly better than the AVR crystal oscillator (I think).
External clock level translation 3.3V to 5V
20MHz is no problem for most buffers, even the ones designed for translating between voltages. Take a look at TI's 74LVC1Gxxx single gate parts, for a nice small solution.
TYVM. :D I have other signal lines that I was level shifting using other means (voltage dividers), so if I have to add an IC for this I'll move those too to a proper level translator chip.
http://focus.ti.com/docs/prod/fo...
I'm leaning towards this one. Can handle 60 MHz. Not very expensive either. :D Has anyone used this IC and can give me his/her comments and/or recommendations? TIA.
Wont a simple HCT be fast enough or a AHCT
Those have a Vil of 2v as any other TTL device.
/Bingo
Even an HC will do in a pinch for the clock. But it will only work in one direction (per IC). :(
I have other signal lines that I was level shifting using other means (voltage dividers), so if I have to add an IC for this I'll move those too to a proper level translator chip.