Crystals higher than 30 MHz (approximately >200 MHz) are commonly operated at sequence resonance exactly where the impedance seems at its bare minimum and equivalent on the collection resistance. For these crystals the sequence resistance is specified ( Predecessor of area mount know-how but nevertheless useful in selected eventualities, for https://bookmarkspecial.com/story19161748/the-2-minute-rule-for-smd-crystal-oscillators