The AD5696RBRUZ data sheet only mentions a sink current of 3 mA. We need to go from a 2.1 kOhm pull up at +5VDC(2.3 mA) to a 1kOhm pull up at +5VDC (5 mA) since we have too many devices on the I2C buss. Can the AD5696RBRUZ sink the 5 mA on the SDA line? The device is a slave so it is not driving the SDL at all so that is not an issue.
Moved to Precision DAC community.
The sink current for the SDA pin was not tested for this device. You could try using 5mA but we cannot guarantee the VOL spec, since it is not within the recommended operating range stated in the datasheet.
I don't think it matters if there are many devices in the I2C bus, but rather on the distance travelled by I2C lines. In some cases, it is better to add a buffer for the I2C signal rather than increase the sink current due to the risk it poses to the VOL.