參數(shù)資料
型號(hào): MB89890
廠商: Fujitsu Limited
英文描述: 8-bit Proprietary Microcontrollers
中文描述: 8位微控制器專有
文件頁(yè)數(shù): 38/45頁(yè)
文件大小: 232K
代理商: MB89890
MB89890 Series
38
7.
Notes on Using A/D Converter
Input impedance of the analog input pins
The A/D converter used for the MB89890 series contains a sample hold circuit as illustrated below to fetch analog
input voltage into the sample hold capacitor for eight instruction cycles after starting A/D conversion.
For this reason, if the output impedance of the external circuit for the analog input is high, analog input voltage
might not stabilize within the analog input sampling period. Therefore, it is recommended to keep the output
impedance of the external circuit low (below 10 k
).
Note that if the impedance cannot be kept low, it is recommended to connect an external capacitor of approx.
0.1
μ
F for the analog input pin.
Error
The smaller the | AVR – AV
SS
|, the greater the error would become relatively.
Order of turning on A/D converter and analog input
Make sure to turn on the digital power supply (V
CC
) before or at the same time with turning on the A/D converter
power supply (AV
CC
, AV
SS
) and application of AN00 to AN07.
To turn off the power, turn off the A/D converter power supply (AV
CC
, AV
SS
) and stop the analog input (AN00 to
AN07) before or at the same time with turning off the digital power supply (V
CC
).
V
OT
V
NT
V
(N + 1)T
V
FST
Digital output
(1 LSB
×
N + V
OT
)
0000
0000
0000
0001
1111
1111
1110
1111
1 LSB =
AVR
256
Linearity error =
Differential linearity error =
Analog input
Actual conversion value
Theoretical conversion value
Total error =
V
NT
– (1 LSB
×
N + V
OT
)
1 LSB
V
( N + 1 ) T
– V
NT
1 LSB
V
NT
– (1 LSB
×
N + 1 LSB)
– 1
1 LSB
Linearity error
Sample hold circuit
C .
Analog channel selector
Close for 8 instruction cycles after starting
A/D conversion.
If the analog input
impedance is higher
than 10 k
, it is
recommended to
connect an external
capacitor of approx.
0.1
μ
F.
Analog input pin
Comparator
R .
Analog Input Equivalent Circuit
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MB89898 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:8-bit Proprietary Microcontroller
MB89898PF 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:8-bit Proprietary Microcontroller
MB89899 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:8-bit Proprietary Microcontroller
MB89899PF 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:8-bit Proprietary Microcontroller
MB898F-R 制造商:IBase Technology (USA) Inc. 功能描述:ATX, LGA775, CORE2DUO, Q965+ICH8, 82566DC GBE LANX1, VGA, CO - Bulk