Hi user4261913, The ADS1246 is now well suited for ratiometric bridge measurements as the AVDD supply voltage cannot be used as a reference voltage. The maximum reference voltage that can be used with the ADS1246 is (AVDD-AVSS) - 1V. The ADS1220 and the ADS124S06 do not have this restriction. You are correct in that the ADS1220 does not have a START pin to be used to start conversions. Instead the START/SYNC command is used. If you want to communicate to 2 separate ADS1220 devices at the same time to start them together should not be an issue. I would suggest that you use an external clock source to drive both devices so that they will have the same clocking characteristics. The internal oscillator can vary from part to part. You will also need to prevent contention from the device output (DOUT/DRDY). When CS goes low on each device, the DOUT/DRDY will be driven and will most likely be at different logic levels. There are a variety of ways to do this. One method would be to use a gated buffer ( SN74LVC1G125 ). The buffer would be gated by the output of a NOR gate ( SN74LVC1G02 ) where the input is connected to each of the device's CS. When both CS goes low, the output of the NOR gate would go high disabling both DOUT/DRDY connections. Individual CS would work as normal. Best regards, Bob B
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