SH7014 Datasheet, PDF (449/754 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

14. Mid-Speed A/D Converter ⎯ SH7016, SH7017 ⎯
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.
Rev.5.00 Sep. 27, 2007 Page 415 of 716
REJ09B0398-0500