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Direction issue

Category: Hardware
Product Number: ADG3308

Hi together,

I have a board using the ADG3308BRUZ a SPI Signal between FPGA (1.8V) and DAC (5.4V).

I face the issue, that all signals originating from FPGA are not translated to to DAC side. When I measure the signals on the A-side of ADG3308, I see clock and data from FPGA. The corresponding pins on Y-Side show a constant high signal.


Tests carried out so far:

Checking power sequencing: VCCY is 5.4V and VCCA is 1.8V. VCCY is stable at 5.4V for 4ms before VCCY starts rising to 1.8V

Rise time on signals originating from the FPGA measured by oscilloscope: 2 to 3ns

The output load is defined by DAC inputs. No other components are connected.

Here is the relevant part of the schematic: The signals on A-side are directly connected to FPGA (AMD MP-SoC)

Has someone an idea what could confuse the ADG3308 to behave that way?

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