Small doubt about ADC analog input range

[ElVale]

I feel stupid for not understanding this. I'm trying to use the PCM1808 (datasheet) 24 bits ADC which has Vcc nominal = 5V and maximun analog input voltage range –0.3 V to (VCC + 0.3 V) < 6.5 V. Also Vref = 2.5V. Data format is 2's complement left justified.

What puzzles me is in Electrical Characteristics where it says Input Voltage = 0.6Vcc Vp-p nominal and in Recommended Operating Conditions where it says Analog input voltage, full scale (–0 dB) at VCC=5V to be 3 Vp-p typical. What do those two facts mean? and at what voltages is all 1s and all 0s? I'd really appreciate some enlightenment .

 

[leozuo]

since vref=2.5V, then all 1s should be at vp-p=2.5V. 3Vp-p maybe means the adc still can work properly at 3V, while if it exceeds 6.5V, Vgs maybe exceed its limits.

That is what I guess. Hope it helps.

 

[ElVale]

OK let me rephrase some things: it actually says Center voltage (VREF) = 0.5 VCC which is confusing because Vref is supposed to be the maximum voltage to convert, not the "center voltage". The other thing is since this is two's complement, all 0s and all 1s would be near 0, so what I really meant is at what voltage is maximum posible value (Hex 7FFFFF) and minimum posible value (Hex 800000).

I'm confused by the 3Vp-p thing in the datasheet at Recommended Operating Conditions: Analog input voltage, full scale, does it mean that the signal is at full scale at 3 V?