andrewsrea
Well-known member
I've been on forum for almost a year and noticed almost monthly, someone posts that their build which uses a charge pump has an audible whine. Which means, the pump frequency and its 1st order subharmonic is in the audio range (typically 10Khz, with a 5Khz subharmonic with pin #1 engaged in boost mode). I bought some recently on Amazon which were supposed to be the 45Khz and were not.
Mouser has both TC1044SCPA and ICL7660SIPAZ, which are both 45Khz with a 22.5Khz subharmonic, that is not audible. I bought and tested 5 of each. Their specs are identical and they do the job with no artifacts. Part numbers are 579-TC1044SCPA and 968-ICL7660SIPAZ. I paid $6.55 for (5) 1044 and $9.35 for (5) 7660, plus $7/99 shipping. Now that I have tested, I'll go with the less expensive TC1044SCPA next time and save a few pennies.
Mouser has both TC1044SCPA and ICL7660SIPAZ, which are both 45Khz with a 22.5Khz subharmonic, that is not audible. I bought and tested 5 of each. Their specs are identical and they do the job with no artifacts. Part numbers are 579-TC1044SCPA and 968-ICL7660SIPAZ. I paid $6.55 for (5) 1044 and $9.35 for (5) 7660, plus $7/99 shipping. Now that I have tested, I'll go with the less expensive TC1044SCPA next time and save a few pennies.