TPS659037: Capacitor on OSC16MCAP

Tony Tang

Part Number: TPS659037
Other Parts Discussed in Thread: AM5718

As there is a bug on AM6718IDK, did not add capacitor on OSC16MCAP. Customer followed the wrong schematic.

Now customer board, the 16MHz crystal does not active, but remain functions work, and the AM5718 also works we are not sure whether it is related the capacitor, I measured on AM5718 IDK, even without the capacitor, the crystal works and outputs 16MHz.

Questions:

#1. what factor result in the 16MHz crystal doesn't output clock?

#2. if doesn't mount the capacitor and connect the pin to GN directly, will it introduce malfunction?

over 4 years ago

0 Layne J over 4 years ago

TI__Genius 12735 points

Hi Tony,

I was assigned to this thread while out of office yesterday, I have now forwarded this thread to the expert for this device and you should receive a response by the end of the day tomorrow.

Best regards,

Layne J

0 Mahmoud Harmouch over 4 years ago

TI__Mastermind 28340 points

Hello Tony,

Sorry I did not well understand your statement. Is the crystal installed? Is the OSC16MCAP pin floating or grounded? Is that possible to show me the partial schematic around the oscillator?

Regards

0 Tony Tang over 4 years ago in reply to Mahmoud Harmouch

TI__Mastermind 29152 points

Mahmoud Harmouch said:
Is the crystal installed? Is the OSC16MCAP pin floating or grounded? Is that possible to show me the partial schematic around the oscillator?

crystal is installed as schematic, OSC16MCAP pin is grounded directly. now the crystal doesn't generate clock, we are not sure whether it related to the grounded OSC16MCAP without 2.2uF capacitor.

0 Mahmoud Harmouch over 4 years ago in reply to Tony Tang

TI__Mastermind 28340 points

Hello,

The OSC16MCAP pin is the supply voltage for the crystal and the 2.2uF is the filtering cap for this pin. It must be installed for functioning correctly. I hope that answer your question.

Regards

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TPS659037: Capacitor on OSC16MCAP