SH7014 datasheet(449/754 Pages) RENESAS

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14. Mid-Speed A/D Converter

⎯ SH7016, SH7017 ⎯

Rev.5.00 Sep. 27, 2007 Page 415 of 716

REJ09B0398-0500

14.6

A/D Conversion Precision Definitions

The mid-speed A/D converter converts analog values input from analog input channels to 10-bit

digital values by comparing them with an analog reference voltage. In this operation, the absolute

precision of the A/D conversion (i.e. the deviation between the input analog value and the output

digital value) includes the following kinds of error.

(1) Offset error

(2) Full-scale error

(3) Quantization error

(4) Nonlinearity error

The above four kinds of error are described below with reference to figure 14.7. For the sake of

clarity, this figure shows 3-bit mid-speed A/D conversion rather than 10-bit mid-speed A/D

conversion. Offset error (see figure 14.7 (1)) is the deviation between the actual A/D conversion

characteristic and the ideal A/D conversion characteristic when the digital output value changes

from the minimum value (zero voltage) of 0000000000 (000 in the figure) to 0000000001 (001 in

the figure ). Full-scale error (see figure 14.7 (2)) is the deviation between the actual A/D

conversion characteristic and the ideal A/D conversion characteristic when the digital output value

changes from 1111111110 (110 in the figure) to the maximum value (full-scale voltage) of

111111111 (111 in the figure). Quantization error is the deviation inherent in the mid-speed A/D

converter, given by 1/2 LSB (see figure 14.7 (3)). Nonlinearity error is the deviation between the

actual A/D conversion characteristic and the ideal A/D conversion characteristic from zero voltage

to full-scale voltage (see figure 14.7 (4)). This does not include offset error, full-scale error, and

quantization error.

SH7014 Datasheet(PDF) 449 Page - Renesas Technology Corp