I have the LTC2668 on my board, I am doing signal verification on it. https://www.analog.com/en/products/ltc2668.html#product-overview
I found that all SEL1~8 outputs have weird drop of voltage before the main pulse as shown in the waveform below (this sudden voltage drops always happens at a specific timing before the SEL main pulse, which suggest it is not a random event but repeatedly stable). It is quite large, reaching to about -1V, although the duration is short, it might cause issue still because my SEL liens are used to operate on memory cell.
I have already checked the input signals DAC_!LDAC, DAC_!CS, DAC_SCLK, DAC_SDO, DAC_SDI, DAC_!TGP, DAC_!CLR, and also the outputs DAC1~8 and Vdd. I don't find any signal changes in these pins around when sudden voltage drop happens.
I wonder what could cause this sudden voltage drop. Because there seems to be no trigger to this event looking from the inputs and outputs.
I found that all SEL1~8 outputs have weird drop of voltage before the main pulse as shown in the waveform below (this sudden voltage drops always happens at a specific timing before the SEL main pulse, which suggest it is not a random event but repeatedly stable). It is quite large, reaching to about -1V, although the duration is short, it might cause issue still because my SEL liens are used to operate on memory cell.
I have already checked the input signals DAC_!LDAC, DAC_!CS, DAC_SCLK, DAC_SDO, DAC_SDI, DAC_!TGP, DAC_!CLR, and also the outputs DAC1~8 and Vdd. I don't find any signal changes in these pins around when sudden voltage drop happens.
I wonder what could cause this sudden voltage drop. Because there seems to be no trigger to this event looking from the inputs and outputs.
