**Part Number:**ADC3563

**Other Parts Discussed in Thread:**ADC3561, ADC3660, ADC3660EVM

Hi team,

i'm analyzing the datasheet of the ADC3563.

I did not find the following data:

- differential input resistance: it's 8 kOhm but what is the value of external termination? In the figure 8.6 the termination is 50 Ohm (25 Ohm on P and N). Must this termination be fixed 50 Ohm or can it assume different values for example 100 Ohm, 200 Ohm ecc..? Obviously, the choice of balun depends on the value of the external termination (for example, impedance ratio 1:1 with termination 50 Ohm, impedance ratio 1:2 with termination 100 Ohm). Is it correct?
- full scale range in dBm: in the datasheet the full scale range is in voltage (=3.2 Vpp), but there isn't the full scale range in dBm. What is this value in dBm? I suppose thath this value depends on the value of the external termination: for example, if the external termination is 50 Ohm the full scale range is 14 dBm, if the external termination is 100 Ohm the full scale range is 11 dBm. Is it correct?
- Noise Figure in dB: in the datasheet of the ADC3563 there is the value of the NSD of -158 dBFS/Hz (with not input signal). To get the noise figure in dB, i have to convert the NSD in dBFS/Hz to dBm/Hz and add it to -174 dBm/Hz but i don't know the full scale range in dBm (NSD(dBm/Hz)=FSR(dBm)+NSD(dBFS/Hz). So, can you provide the noise figure value of the ADC?
- Noise spectral Density: in the datasheet the NSD for the ADC3563 is -158 dBFS/Hz with no input signal. So if i want the NSD value with input signal (for example at 20 MHz) i can take the SNR value at 20 MHz (=81.6 dBFS) and add it to the Nyquist factor 10log10(Fs/2) with Fs=65 MHz. So the NSD at 20 MHz = -81.6-75.12=-156.7 dBFS/Hz. Is it correct?

Thank you in advance.

Best Regards,

Matteo Ricci