MB96F313ASBPMC-GSE2 Fujitsu, MB96F313ASBPMC-GSE2 Datasheet - Page 68

• Manufacturer Part Number: MB96F313ASBPMC-GSE2
• Description: MCU, 16BIT, 16FX, 96K FLASH, 48LQFP
• Manufacturer: Fujitsu

Specifications of MB96F313ASBPMC-GSE2

• No. Of I/o's: 36
• Ram Memory Size: 8KB
• Cpu Speed: 56MHz
• No. Of Timers: 3
• No. Of Pwm Channels: 14
• Digital Ic Case: RoHS Compliant
• Core Size: 16bit
• Program Memory Size: 96KB
• Oscillator Type: Internal, External
• Controller Family/series: MB96310

MB96310 Series
Accuracy and setting of the A/D Converter sampling time
68
If the external impedance is too high or the sampling time too short, the analog voltage charged to the internal
sample and hold capacitor is insufficient, adversely affecting the A/D conversion precision.
To satisfy the A/D conversion precision, a sufficient sampling time must be selected. The required sampling time
depends on the external driving impedance R
the AV
The sampling time should be set to minimum “7τ“. The following approximation formula for the replacement
model above can be used:
• Do not select a sampling time below the absolute minimum permitted value
• If the sampling time cannot be sufficient, connect a capacitor of about 0.1 μF to the analog input pin. In this
• A big external driving impedance also adversely affects the A/D conversion precision due to the pin input
• The accuracy gets worse as |AVRH - AVRL| becomes smaller.
(0.5μs for 4.5V ≤ AV
case the internal sampling capacitance C
leakage current I
leakage current of pin input and comparator during sampling). The effect of the pin input leakage current I
cannot be compensated by an external capacitor.
T
samp
cc
voltage level. The following replacement model can be used for the calculation:
[min] = 7 × (R
R
C
C
R
C
Source
ext
ext
IN
ADC
ADC
: capacitance of MCU input pin: 15pF (max)
: external driving impedance
: capacitance of PCB at A/D converter input
: resistance within MCU: 2.6kΩ (max) for 4.5V ≤ AV
: sampling capacitance within MCU: 10pF (max)
IL
(static current before the sampling switch) or the analog input leakage current I
cc
ext
≤ 5.5V; 1.2 μs for 3.0V ≤ AV
× (C
R
ext
ext
+ C
Analog
input
C
IN
ext
) + (R
12kΩ (max) for 3.0V ≤ AV
ext
ADC
C
+ R
Sampling switch
IN
ext
will be charged out of this external capacitance.
, the board capacitance of the A/D converter input pin C
ADC
) × C
cc
< 4.5V).
ADC
)
R
ADC
MCU
cc
cc
< 4.5V
≤ 5.5V
C
ADC
Comparator
DS07-13808-2E
AIN
ext
(total
and
IL