AD converter Parameters

Resolution,Reference VoltageAll those people on earth know this.

 

When "reference voltage" and "resolution" are determined, the difference between each two values, that is,"Step Size".

The above "Step quantity" is called 1 in ADLSB(Least effective bit, least significant bit) represents the voltage value.

Take a 5 V reference voltage and a 10-bit ad as an example. The voltage value that 1lsb can represent is:

Voltage value expressed by 1lsb = reference voltage 5 V/(0x3ff + 1) = 4.88mv

 

For any ad, the digital signal output after quantification is stepped in at the voltage of 1 LSB. the voltage between 1 LSB will be entered or discarded according to certain rules, the error caused by this process is called"Quantization Error", Quantization error is a theoretical error and cannot be eliminated.

 

0.5 LSB non-linearity:

After the offset error and gain error are corrected, the deviation between the digital signal value obtained after conversion and the actual input voltage signal is measured in multiples of 1 LSB.

 

+ 2 ~ -Absolute precision of 2lsb:

After all the error factors are included, the error between all the converted digital signal values and the actual input voltage signals is measured in multiples of 1 LSB.

 

13-260 us conversion time:

The sampling rate at the highest resolution is up to 15 ksps:

Both of them describe the conversion speed of AD. The conversion of a successive approximation ad is performed under the guidance of a clock. The higher the clock speed, the shorter the corresponding conversion time, but at the cost of the conversion accuracy. The conversion time of 13-260 us is the conversion time obtained by selecting the clock in the Continuous Conversion Mode.

 

Noise Suppression Based on sleep mode:

To further reduce the noise during the ad ing, the AVR allows CPU to be transferred to sleep mode during the ad ing.

 

Note:

When there are other voltage reference sources connected to Aref, do not select the internal 1 V voltage reference source. Otherwise, two voltage reference sources will be short-circuited and the device will be burned out!

When selecting an internal 1 V voltage reference source, only one capacitor with good high-frequency characteristics and low leakage current (such as porcelain chip capacitor) can be connected to the Aref end to help stabilize the output voltage of the internal voltage reference source.