i.MX27 external oscillator specs

[Sebster]

Hello all,

I am looking for the specs (requirements) for the 26M oscillator on the imx27. I want to use an external oscillator.  Would you have factory guidelines for:

1. Voltage levels,
2. PPM (stability)
3. AD or DC coupling
4. Duty cycle
5. Etc.

Thanks in advance

Cheers

Seb

[VladanJovanovic]

Here are specs I believe should be correct:

[Sebster]

Hi Vladan,

Thanks for your input. However my question is related to the "oscillator" specs not the crystal specs.  A 26MHz clock is going to be feed into the EXTAL26M input on the chip. I need to know the required specs of that clock.

Thanks
Seb

[FlorentAuger · Accepted solution]

The XTAL26M and EXTAL26M I/Os are supplied by OSC26VDD, so the level should be the same.

If connected to XTAL26M, the signal will go through the internal osc amplifier.

If connected to EXTAL26M, the signal will bypass the internal osc amplifier.

Both should be valid, and in any case, the other input is left floating.

The specifications of the oscillator must be aligned with what you intend to do with that clock. It can be used to either feed a PLL, or routed directly to a peripheral.

The specifications of the internal oscillator are below, so your external oscillator will likely have something similar.