Other Parts Discussed in Thread: DAC53401,
DAC53401 outputs LOW for ACK, but there is no description about Vol specification of SDA pin in the datasheet.
I believe it has Vol(max)=0.4V capability at IOL=3mA the same as other I2C device.
Could you make sure the Vol specification for DAC53401-Q1? It needs the calculation for the pullup resistor.