UPD78F0078GK-9ET-A Renesas Electronics America, UPD78F0078GK-9ET-A Datasheet - Page 240

• Manufacturer Part Number: UPD78F0078GK-9ET-A
• Manufacturer: Renesas Electronics America

Specifications of UPD78F0078GK-9ET-A

• Lead Free Status / Rohs Status: Supplier Unconfirmed

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13.5 How to Read A/D Converter Characteristics Table
(1) Resolution
(2) Overall error
(3) Quantization error
Here, special terms unique to the A/D converters are explained.
This is the minimum analog input voltage that can be identified. That is, the percentage of the analog input voltage
per 1 bit of digital output is called 1 LSB (Least Significant Bit). The percentage of 1 LSB with respect to the
full scale is expressed by %FSR (Full Scale Range).
When the resolution is 10 bits,
1 LSB = 1/2
Accuracy has no relation to resolution, but is determined by overall error.
This shows the maximum error value between the actual measured value and the theoretical value.
Zero-scale error, full-scale error, integral linearity error, differential linearity error and errors that are combinations
of these express the overall error.
Note that the quantization error is not included in the overall error in the characteristics table.
When analog values are converted to digital values, a 1/2 LSB error naturally occurs. In an A/D converter, an
analog input voltage in a range of 1/2 LSB is converted to the same digital code, so a quantization error cannot
be avoided.
Note that the quantization error is not included in the overall error, zero-scale error, full-scale error, integral
linearity error, and differential linearity error in the characteristics table.
1 …… 1
0 …… 0
= 0.098%FSR
Figure 13-11. Overall Error
10
0
= 1/1024
Ideal line
Analog input
CHAPTER 13 A/D CONVERTER
Overall
User’s Manual U14260EJ4V0UD
error
AV
REF
1 …… 1
0 …… 0
Figure 13-12. Quantization Error
0
1/2 LSB
Analog input
1/2 LSB
Quantization error
AV
REF