Hello;
Fairchild Semi has obsoleted a 74hc4046A chip on a legacy product of ours and I need a drop in replacement. I have tried to drop in the TI SN74hc4046A chip but now the VCO runs at roughly 287 KHz rather than 153.6 KHz. Nothing else has changed in the circuit. Both datasheeta are closely comparable. What differences are there between the two chips that may casue this problem?
Thank you.