AN1812 datasheet(20/34 Pages) STMICROELECTRONICS

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11 Result

AN1812

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Figure 15. Error vs input for positive input voltages

Note:

From the readings (Table 1, Figure 15), we can notice that for the positive input between 0 to 1V

the maximum error is around 500 uV for the average of 16 conversions. The difference between

the maximum and minimum values in a loop of 16 is around 500 uV. This shows that averaging

has increased the accuracy. The accuracy without averaging is approx 1mV.

The variations in 16 values can be due to changes in the input voltage itself, as the time taken

for 16 readings is very long (around 16 s).

11.2

Negative input

Similar to the positive input voltages, the readings for negative input voltages are taken in a

loop of 16 as shown in Figure 16.

Figure 16. Results for negative input

Table 2 shows the readings for negative input voltages ranging from 0 to -1V with same

parameter notations.

Table 2.

Results for negative input voltages

Sl no

Vin (Taken from Multi-

meter) (mV)

Vmeasured (mV)

Difference

(Vmeasured - Vin)

(mV)

Error in Max and min

input measured (mV)

-9.23

-9.17

0.06

0.43

-18.92

-18.84

0.08

0.14

-28.96

-29.04

-0.08

0.27

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