RT117x Driving RTC_XTALI using External oscillator with 1.8V output Is it possible to drive RTC_XTALI with external clock with dc level of 1.8V? since ensuring that external clock match VDD_SNVS_ANA will increase the design complexity. Also 1.8V is below the absolute maximum rating of clock inputs. Marwan_2-1786726380644.pngMarwan_2-1786726380644.pngMarwan_2-1786726380644.png Re: RT117x Driving RTC_XTALI using External oscillator with 1.8V output Hi @Marwan,
As stated in the Hardware Development Guide for the MIMXRT1160/1170 Processor, if you want to feed an external low-frequency clock into RTC_XTALI, the RTC_XTALO pin must remain unconnected or be driven by a complementary signal. The logic level of this forcing clock must not exceed the VDD_SNVS_DIG level.
Additionally, the i.MX RT1170 Crossover Processors Data Sheet states that VDD_SNVS_DIG has an operating voltage range of 0.81 V to 0.95 V, with a typical value of 0.85 V.
This means that a 1.8 V signal would exceed the VDD_SNVS_DIG voltage level. Best Regard, Pablo Re: RT117x Driving RTC_XTALI using External oscillator with 1.8V output Hi @Pablo_Ramos There is discrepency in the documents, as mention in other posts. The datasheet state that it is referenced to VDD_SNVS_ANA. Kind Regards, Marwan Re: RT117x Driving RTC_XTALI using External oscillator with 1.8V output Hi @Marwan,
I apologize for the inconvenience.
Your observation is correct, and I will remark this internally.
For now, please refer to the datasheet and ensure that the external clock into RTC_XTALI does not exceed the VDD_SNVS_ANA supply level.
In this case, an external clock with dc level of 1.8V oscillator may be used, as long as VDD_SNVS_ANA is guaranteed to be at or above 1.8 V in the design.
Best Regards, Pablo Re: RT117x Driving RTC_XTALI using External oscillator with 1.8V output Hi @Pablo_Ramos, thanks for your reply, 1 - is there away to guarantee that? since this power rail is internally generated and there is no mention about whether is it programmable or not. 2 - is there a VDD_SNVS_ANA variance between IC batches? Kind regards, Marwan
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