CMOS CLOCK OSCILLATOR CE3290-FREQ. In the event we do not have stock. The following series can be substituted for CE3290-freq. The frequencies must be the same: CE3292- CE3291- CE3390-FREQ. In the event we do not have stock. The following series can be substituted for CE3390-freq. The frequencies must be the same: CE3392- CE3391- 5-0704-59