
MB90455 Series
69
7.
Notes on A/D Converter Section
Use the device with external circuits of the following output impedance for analog inputs:
Recommended output impedance of external circuits are:  Approx. 3.9 k
 or lower (4.5 V 
≤
 AVcc 
≤
 5.5 V)
(sampling period=2.00 
μ
s at 16-MHz machine clock), Approx. 11 k
 or lower (4.0 V 
≤
 AVcc < 4.5 V) (sampling
period=8.0 
μ
s at 16-MHz machine clock).
If an external capacitor is used, in consideration of the effect by tap capacitance caused by external capacitors
and on-chip capacitors, capacitance of the external one is recommended to be several thousand times as high
as internal capacitor.
If output impedance of an external circuit is too high, a sampling period for an analog voltage may be insufficient.
 About errors
As [AVR-AVss] become smaller, values of relative errors grow larger.
8.
Flash Memory Program/Erase Characteristics
Parameter
Conditions
Value
Unit
Remarks
Min
Typ
Max
Sector eraset time
T
A
=
+
 25 
°
C
V
CC
=
 5.0 V
1
15
s
Excludes 00
H
 programming 
prior to erasure
Chip erase time
4
s
Excludes 00
H
 programming 
prior to erasure
Word (16 bit width) 
programming time
16
3,600
μ
s
Except for the over head 
time of the system
Program/Erase cycle
10,000
cycle
C
R
 Analog input circuit model
Note : Use the values in the figure only as a guideline.
MB90F455 (S) /F456 (S) /F457 (S)  and MB90455 (S) /456 (S) /457 (S) 
4.5 V
≤
  AV
CC
≤
5.5 V
4.0 V
≤
  AV
CC
<
4.5 V
R : 2.35 k
,  C : 36.4 pF
R : 16.4 k
,  C : 36.4 pF
Comparator
Analog input