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ADV7611 Power Supplies Sequence

Question asked by Padrig on Aug 13, 2012
Latest reply on Aug 31, 2012 by LukaszNowak

Hi everybody,

 

I'm currently testing a board using ADV7611 and ADV7513 chips.

The I2C communication with the ADV7513 chips is working but not with the ADV7611 (no acknowledge of the I2C address 0x98 or 0X9A).

 

So, I have checked everything around the chip:

- chip orientation

- pull-up resistors value on I2C lines

- CAD implementation

- supplies values and stability

- the reset pin is held low during power up sequence

- no I2C access after the reset pin is released

 

I have an evaluation board to compare my measure and the only difference between my board and the eval board is the power sequence.

The ADV7611 chip need a power up sequence for the 3V3 and 1V8 supplies.

I respect the sequence (1V8 ramp after 3V3 stable) but the 1V8 supply is only establish 180ms after the 3V3 supply is stable (the 1V8 regulator is driven by a voltage monitor).

On the evaluation board this time between the 3V3 and 1V8 ramp is only 12ms.

 

I didn't find any recommendation on the datasheet or on the UG-180 for this time between the two ramp.

This is a problem to have 180ms between the two supplies ramp? The chip can be blocked if the power up sequence is too long?

 

Thank you.

 

Best regards.

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