RX21A_15 Datasheet, PDF (110/132 Pages) Renesas Technology Corp – Renesas MCUs

RX21A Group
5. Electrical Characteristics
3FFh
Full-scale error
A/D converter
output code
Integral nonlinearity
error (INL)
Actual A/D conversion
characteristic
Ideal line of actual A/D
conversion characteristic
Ideal A/D conversion
characteristic
Differential nonlinearity error (DNL)
1-LSB width for ideal A/D
conversion characteristic
Differential nonlinearity error (DNL)
1-LSB width for ideal A/D
conversion characteristic
Absolute accuracy
000h
0
Offset error
Analog input voltage
Figure 5.62 Illustration of A/D Converter Characteristic Terms
VREFH0
(full-scale)
Absolute accuracy
Absolute accuracy is the difference between output code based on the theoretical A/D conversion characteristics, and the
actual A/D conversion result. When measuring absolute accuracy, the voltage at the midpoint of the width of analog
input voltage (1-LSB width), that can meet the expectation of outputting an equal code based on the theoretical A/D
conversion characteristics, is used as an analog input voltage. For example, if 10-bit resolution is used and if reference
voltage VREFH0 = 2.56 V, then 1-LSB width becomes 2.5 mV, and 0 mV, 2.5 mV, 5.0 mV, ... are used as analog input
voltages.
If analog input voltage is 20 mV, absolute accuracy = ±4 LSB means that the actual A/D conversion result is in the range
of 004h to 00Ch though an output code, 008h, can be expected from the theoretical A/D conversion characteristics.
Integral nonlinearity error (INL)
Integral nonlinearity error is the maximum deviation between the ideal line when the measured offset and full-scale
errors are zeroed, and the actual output code.
R01DS0129EJ0110 Rev.1.10
Aug 28, 2014
Page 110 of 132