Overview of 16-bit SDADC

AN4207

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Doc ID 023945 Rev 1

Figure 7.

Gain error in SDADC

Two types of gain are implemented in the SDADC:

Analog gain: x1/2, x1, x2, x4, x8

Digital gain: x16 and x32.

Only the analog gains are considered in gain calibration.

Gain calibration requires an external accurate reference and it is performed by applying the

accurate reference voltage (AccRef) at the SDADC input and getting the SDADC output.

The gain is computed as following: AccRef/(Output x Vref/65535)

The computed gain can be stored in non-volatile memory (Flash memory) and used during

acquisition phase

Note:

Before running gain calibration it is mandatory to run offset calibration.

Analog input

Digital value

1

Positive gain error

2

Negative gain error

3

Null gain error

MSv31133V1