RX230 Datasheet, PDF (147/177 Pages) Renesas Technology Corp – 54-MHz 32-bit RX MCUs, built-in FPU, 88.56 DMIPS, up to 512-KB flash memory

RX230 Group, RX231 Group
5. Electrical Characteristics
FFFh
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
VREFH0
(full-scale)
Figure 5.68 Illustration of A/D Converter Characteristic Terms
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 12-bit resolution is used and if reference
voltage (VREFH0 = 3.072 V), then 1-LSB width becomes 0.75 mV, and 0 mV, 0.75 mV, 1.5 mV, ... are used as analog
input voltages.
If analog input voltage is 6 mV, absolute accuracy = ±5 LSB means that the actual A/D conversion result is in the range
of 003h to 00Dh, although an output code, 008h, can be expected from the theoretical A/D conversion characteristics.
Integral non-linearity error (INL)
The integral non-linearity error is the maximum deviation between the ideal line when the measured offset and full-scale
errors are zeroed, and the actual output code.
R01DS0261EJ0110 Rev.1.10
Oct 30, 2015
Page 147 of 177