Timeline for How to build an 8 MHz oscillator with a crystal?
Current License: CC BY-SA 4.0
7 events
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| Feb 11, 2023 at 16:55 | comment | added | TimWescott | Actually at least the original 7400-series logic and (if I recall correctly) 74LS00-series has a fairly nice linear region. You just need to use a much lower resistance at R1, and accept that the crystal may need to be driven harder (so, no itty-bitty crystals). I'm not sure about it hitting 8MHz, but there were a lot of commercial designs in the 1980's that used a 7400-series logic gate as the active element in a crystal oscillator. | |
| Feb 11, 2023 at 11:46 | vote | accept | Bart Friederichs | ||
| Feb 11, 2023 at 11:44 | comment | added | Andy aka | @BartFriederichs try this: ti.com/lit/an/scha004/… | |
| Feb 11, 2023 at 11:32 | comment | added | Bart Friederichs | Could you elaborate a little on the buffered/unbuffered thing? The 7400 datasheet doesn't mention any of it. | |
| Feb 11, 2023 at 11:28 | comment | added | LvW | Yes - such a resistor is necessary. Otherwise C2 would have (nearly) no influence on the feedback voltage. But is must be your goal to have 3rd-order R-C-L-C lowpass in the feedback path (the crystal works as an inductor). | |
| Feb 11, 2023 at 11:23 | history | edited | Andy aka | CC BY-SA 4.0 |
added 435 characters in body
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| Feb 11, 2023 at 11:17 | history | answered | Andy aka | CC BY-SA 4.0 |