At 11:36 AM 2/9/2004, Mccauley, Daniel H wrote: >Regarding the 4049/4050 option, you state that the Vdd must be 5V on >this chip. Does this mean that this chip can only be used when converting >5V CMOS >to the PIC? Or can I have a 12-15V CMOS output interface to a 5V >4049/4050 input and >the output of the 4049/4050 will provide proper level shifting for the PIC. The 4050 does not have ESD protect diodes from the input pins to Vdd. You can apply any voltage between 0V thru 15V (18V for certain manufacturers) to an input pin regardless of the level at Vdd. Vdd affects the threshold voltage and the output voltage. In other words, if your PIC is operating from 5V, then the 4050 should be as well. I'm scraping cobwebs off old memories here - also look at the 4506. It can do 6 channels of level translation from hi Vdd to lo Vdd or vice versa. It does this by having 2 power pins (Vcc & Vdd). But all 6 channels have to be the same level - in other words, you can't do 3 channels of hi Vdd to lo Vdd & 3 channels of lo Vdd to hi Vdd. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 20 years of Engineering Innovation (1984 - 2004) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body