ZHCSQN6 May 2022 ADC3644
PRODUCTION DATA
The ADC voltage reference can be selected using the REFBUF pin. Even though there is an internal 100 kΩ pull-up resistor to AVDD, the REFBUF pin should be set to a voltage externally and not left floating.
When using a voltage divider to set the REFBUF voltage (R1 and R2 in Figure 8-44), resistor values < 5 kΩ should be used.
REFBUF VOLTAGE | VOLTAGE REFERENCE OPTION | CLOCKING OPTION |
---|---|---|
> 1.7 V (Default) | External reference | Differential clock input |
1.2 V (1.15-1.25V) | External 1.2V input on REFBUF pin using internal gain buffer | Differential clock input |
0.5 - 0.7V | Internal reference | Differential clock input |
< 0.1V | Internal reference | Single ended clock input |