HD6417706 RENESAS [Renesas Technology Corp], HD6417706 Datasheet - Page 556

• Manufacturer Part Number: HD6417706
• Description: Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

19.8
The A/D converter compares an analog value input from an analog input channel to its analog
reference value and converts it into 10-bit digital data. The absolute accuracy of this A/D
conversion is the deviation between the input analog value and the output digital value. It includes
the following errors:
These four error quantities are explained below using figure 19.10. In the figure, the 10 bits of the
A/D converter have been simplified to 3 bits.
Offset error is the deviation between actual and ideal A/D conversion characteristics when the
digital output value changes from the minimum (zero voltage) 0000000000 (000 in the figure) to
000000001 (001 in the figure) (figure 19.10, item (1)). Full-scale error is the deviation between
actual and ideal A/D conversion characteristics when the digital output value changes from the
1111111110 (110 in the figure) to the maximum 1111111111 (111 in the figure) (figure 19.10,
item (2)). Quantization error is the intrinsic error of the A/D converter and is expressed as 1/2 LSB
(figure 19.10, item (3)). Nonlinearity error is the deviation between actual and ideal A/D
conversion characteristics between zero voltage and full-scale voltage (figure 19.10, item (4)).
Note that it does not include offset, full-scale or quantization error.
Rev. 4.00, 03/04, page 510 of 660
Offset error
Full-scale error
Quantization error
Nonlinearity error
Digital output
FS: Full-scale voltage
111
110
101
100
011
010
001
000
Definitions of A/D Conversion Accuracy
0
1/8 2/8 3/8 4/8 5/8 6/8 7/8 FS
Figure 19.10 Definitions of A/D Conversion Accuracy
characteristics
conversion
(3) Quantization
Ideal A/D
error
Analog input
voltage
Digital output
characteristics
(1) Offset error
conversion
Ideal A/D
Actual A/D
convertion
characteristics
(4) Nonlinearity
error
(2) Full-scale error
Analog input
voltage
FS