Differential ADC voltage lower than VREF but VINP/VINN higher than VREF

Question

Hello, 
 I need to use the ADC with 600mV internal voltage, ADC Gain stage = 1. 
 The input signal on VINP vary from 750mV to 1750mV, and input signal on VINN is fixed at 1250mV. 
 VINP and VINN are both higher than VREF but the resulted differential voltage is +/-500mV. 
 is the ADC can work in this condition ? 
 Best regards,

hmolesworth · Answer

I think I disagree, although stand to be corrected. In single-ended mode the input range is indeed limited from 0-600mV as described above but in differential mode not so: 
 Input range = (+- 0.6 V or +-VDD/4)/Gain 
 In differential mode the difference is applied to the true differential ADC and so can range from Vin+ 600mV below Vin- to Vin+ 600mV above Vin-, a true span of 1200mV centered about the differential mid point (1250 mV in the question) provided neither input goes outside the GND and VDD limits. 
 So yes the SAADC should work correctly in the original question.

Differential ADC voltage lower than VREF but VINP/VINN higher than VREF

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