I think you need to test this... My results indicate a longer startup time. KreAture ----- Original Message ----- From: "Olin Lathrop" To: Sent: Saturday, April 05, 2003 4:20 PM Subject: Re: [EE]: Correct way to hook up MAX232 VS+/VS- pins > > Take VS+: To charge an capacitor from 0 to 10v or more potential takes > > more power than charging it to 5v wich would be 10v thanks to the 5v > > offset if connected as manufacturer reccommends. Result is longer > > startup time, but yes it may work. > > This is just plain wrong. In either case, the capacitor starts at 5V with > respect to ground and ends up at 10V. The incremental charge to get it > there is the same regardless of where the other end is tied. The only > difference is the voltage rating required of the capacitor. As long as > the other side of the capacitor is tied to a voltage with no AC component > (constant with respect to ground), the charge pump will operate > identically. dQ still equals C * dV either way. > > The real issue is where you want to dump the ripple current. I prefer to > keep the supply rail as clean as possible, so I bypass the MAX232A at the > chip and tie the other end of the +10V capacitor to ground. > > > ***************************************************************** > Embed Inc, embedded system specialists in Littleton Massachusetts > (978) 742-9014, http://www.embedinc.com > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body