Contents
What kind of input does an ADC use?
Pseudo-Differential True Bipolar. Pseudo-Differential Inputs. An ADC with pseudo-differential inputs digitizes the differential analog input voltage (IN + – IN–) over a limited range. The IN input has the actual analog input signal, while the IN– input has a restricted range.
What causes an ADC to make an error?
One of the biggest potential sources of errors in an ADC with an internal or external reference is the reference voltage. Often, if the reference is included on-chip, it is not specified adequately.
What should the voltage of an ADC pin be?
An ADC with fully-differential inputs digitizes the differential analog input voltage (IN+ – IN–) over a span of ±V. FS. In this range, the IN+ and IN– pins should be driven 180º out-of-phase with respect to each other, centered on a fixed common mode voltage, for example, V. REF/2 ±50mV.
What happens when code 10 is missing in ADC?
When the input voltage is swept, Code 10 will be missing. When DNL-error values are offset (that is, -1LSB, +2LSB), the ADC transfer function is altered. Offset DNL values can still in theory have no missing codes. The key is having -1LSB as the low limit.
How many differential channels does a differential ADC have?
A lot of differential ADCs can be configured to give you twice the channels in single-ended mode. For example the AD7265 has 6 differential channels and 12 single ended channels. A regular ADC samples it’s inputs in the range 0V to AVcc, where AVcc is often configurable (5V, 2.56V, user input etc).
How is differential ADC used to measure DC offset?
A differential ADC shifts the lower reference from 0V to some other value – either a user input on a second analog input, or a internal reference. This is helpful for measuring small signals that have a large DC offset – eg measuring changes of 100mV in the range 2.5-2.6V.