I used a TI CD74HC7046A instead of the original National MM74HC4046, but the "A" grade part was specified for about 4.5 times the maximum operating frequency. I made use of the built-in lock detector feature of the 7046 which the 4046 doesn't have. Oddly enough, TI doesn't seem to make non-"A" grade 74HC VCOs and Fairchild continuing the National parts only seems to make non-"A" grade 74HC VCOs. Also, I built the circuit on a perfboard instead of a breadboard, greatly reducing the parasitic capacitance between pins. This also made the National LMC555 circuit work according to formula at about 1.5MHz. The 7046 circuit worked at up to 22.6MHz at 4.5V, also according to formula.
Brad ----- Original Message ----- To: "Multiple recipients of list CHIPDIR-L" <[EMAIL PROTECTED]> Sent: Thursday, September 02, 2004 10:25 AM > Brad O'Dell enlightened us > > I got the circuits to work fine now, on a circuit board. Thanks to all who contributed. > > Brad > > > How, as a matter of interest? Different manufacturer? > -- > > With best Regards, > > > Declan Moriarty. > -- > Author: Declan Moriarty > INET: [EMAIL PROTECTED] > > Fat City Hosting, San Diego, California -- http://www.fatcity.com > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB CHIPDIR-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). -- Author: Brad O'Dell INET: [EMAIL PROTECTED] Fat City Hosting, San Diego, California -- http://www.fatcity.com --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
