i.MX25: Apply 3.3V to 1.5V OSC32K_XTAL & OSC_BYP

[norishinozaki]

Hello Champs,

My customer designed a board which applys 3.3V external clock to 1.5V OSC32K_XTAL and OSC_BYP.

They are using an external clock device which output level is 3.3V.

They measured voltages at OSC32K_XTAL and OSC_BYP, which show 2.3V.

Seems like amount of 1.0V voltage is absorbed in i.MX25.

The boards are out in the market already and they would like to know what can be happened in the boards.

Can the applied 3.3V cause shortage of life time or something?

Best regards,

Nori Shinozaki

[art]

The situation you describe is out of spec and, of course, can affect the product long-term stability and lifetime. The customer has to use an external level shifting circuit to get the input clock signal within the NVCC_DRYICE range, that is typically about 1.2 - 1.3V.

Have a great day,
Artur

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[norishinozaki]

Hello Atur,

Thanks, I understand the NVCC_DRYICE varies on QVCC in normal run mode.

For pads belonging to DRYICE power rail, when adjuesting voltage level or puling-up to VDD,  which VDD should they refer to, NVCC_DRYICE or QVCC?

Because the customer is not using DRYICE for reduced power mode and for security.

Best regards,

Nori Shinozaki