Contents
Do you need separate ground supplies for analog and digital?
This particular problem can often be avoided by having separate power supplies (and, thus, separate ground returns) for the various portions of the circuit. For example, separate analog and digital supplies with separate analog and digital grounds, joined at the star point, are common in mixed-signal applications.
Is there a conflict between analog and digital ground?
There is, in fact, no conflict. The labels, “analog ground” and “digital ground,” on these pins refer to the internal parts of the converter to which the pins are connected and not to the system grounds to which they must go.
Why is it necessary to separate analog and digital circuitry?
On the other hand, analog circuitry is quite vulnerable to noise—on both power supply rails and grounds—so it is sensible to separate analog and digital circuitry to prevent digital noise from corrupting analog performance. Such separation involves separation of both ground returns and power rails—which can be inconvenient in a mixed-signal system.
Do you need analog and digital ground pins?
Most such devices provide separate analog and digital ground pins and recommend that they both be connected to the analog ground, with the recognition that this will introduce some digital noise into the analog system.
Can a 3.3V input drive a 5V input?
For example 3.3V TTL logic shares the 0.8V and 2V thresholds for logic 0 and logic 1 transitions with 5V TTL logic, so a 3.3V TTL output can drive a 5V TTL input without any extra hardware required.
Where are the analog and digital ground pins on an ADC?
The labels, “analog ground” and “digital ground,” on these pins refer to the internal parts of the converter to which the pins are connected and not to the system grounds to which they must go. For an ADC, these two pins should generally be joined together and to the analog ground of the system.
What’s the difference between 2V and 5V logic?
If your introduction to digital electronics came more years ago than you’d care to mention, the chances are you did so with 5V TTL logic. Above 2V but usually pretty close to 5V is a logic 1, below 0.8V is a logic 0.