AD7329 enable true differential mode

Hi Eutim,

          When the AD7329 is configured in true differential mode, the signal going into the Vin+ and Vin- are 180degrees out of phase but of the same amplitude. This is detailed on page 20 of the datasheet. The statement you mentioned, "When the AD7329 is in true differential mode, the voltage applied to this (ADCin-) pin is a high voltage signal (±10 V, ±5 V, ±2.5 V, or 0 V to +10 V)." means that Vin- can accept this voltage ranges when set at differential mode. By the way, in your application where do your signal coming from? If the singnal is a single ended and you want to have true differential configuration, there are driver circuit that would enable or convert this signal into diffetential.

Regards,

Jonathan

Hi Jonathan,

Thanks for your quick reply!

I understand that Vin can accept signals within the range of  (±10 V, ±5 V, ±2.5 V, or 0 V to +10 V).

I want to have a switch on my PCB that allows me to change the ADC from being in the single-ended, pseudo, or true differential.

Right now I have a jumper connecting ADCin- to AGND (single-ended mode), a jumper connecting ADCin- to MUXout- (pseudo-differential mode). However, I don't understand what to tie to the ADCin- pin to enable true-differential mode.

Regards,

eutim

Hi Eutim,

     The AD7329 can be configured in a full differential mode by writing to the control register and setting Mode 1 =1 and Mode 0 = 0. This is discussed in the control register section of the datasheet. You can also refer to Table 12 for details. After the input is set to full differential mode, the ADCIn+ and ADCIn- can accept input ranges specified in the datasheet but they are 180 degree out-of-phase. For example for a +/-5V input range, when ADCin+ is +5V ADCin- should be -5V. Typically the figure below how the full differential signal going into Vin.

Regards,

Jonathan

Hi Eutim,

     The AD7329 can be configured in a full differential mode by writing to the control register and setting Mode 1 =1 and Mode 0 = 0. This is discussed in the control register section of the datasheet. You can also refer to Table 12 for details. After the input is set to full differential mode, the ADCIn+ and ADCIn- can accept input ranges specified in the datasheet but they are 180 degree out-of-phase. For example for a +/-5V input range, when ADCin+ is +5V ADCin- should be -5V. Typically the figure below how the full differential signal going into Vin.

Regards,

Jonathan