
MB90435 Series
36
 (2) Clock Output Timing
 (MB90F438L (S) /437L (S) /438L (S)  : V
CC
=
 3.5 V to 5.5 V, V
SS
=
 AV
SS
=
 0.0 V, T
A
=
40 
°
C to 
+
105 
°
C)
 (MB90F439 (S) /439 (S) /V540G : V
CC
=
 5.0 V 
±
 10
%
, V
SS
=
 AV
SS
=
 0.0 V, T
A
=
40 
°
C to 
+
105 
°
C)
 (3) Reset and Hardware Standby Input Timing
 (MB90F438L (S) /437L (S) /438L (S)  : V
CC
=
 3.5 V to 5.5 V, V
SS
=
 AV
SS
=
 0.0 V, T
A
=
40 
°
C to 
+
105 
°
C)
 (MB90F439 (S) /439 (S) /V540G : V
CC
=
 5.0 V 
±
 10
%
, V
SS
=
 AV
SS
=
 0.0 V, T
A
=
40 
°
C to 
+
105 
°
C)
“t
cp
” represents one cycle time of the machine clock.
Oscillation time of oscillator is time that amplitude reached the 90
%
. In the crystal oscillator, the oscillation time is 
between several ms to tens of ms. In FAR/ceramic oscillator, the oscillation time is between handreds of 
μ
s to 
several ms. In the external clock, the oscillation time is 0 ns.
Any reset can not fully initialize the Flash Memory if it is performing the automatic algorithm.
Parameter
Symbol
Pin name
Condition
Value
Units
Remarks
Min
Max
Cycle time
CLK
↑
→
CLK
↓
t
CYC
CLK
V
CC
=
 5 V 
±
 10
%
62.5
ns
t
CHCL
20
ns
Parameter
Symbol
Pin 
name
Value
Units
Remarks
Min
Max
Reset input time
t
RSTL
RST
4 t
CP
ns
Under normal operation
Oscillation time of 
oscillator 
+
 4 t
CP
ms
In stop mode
100
μ
s
Pseudo timer mode 
(MB90437L (S) /438L (S) ) 
4 t
CP
ns
Pseudo timer mode
 (Other than MB90437L (S) 
/438L (S) ) 
2 t
CP
μ
s
In sub clock mode, sub 
sleep mode and watch 
mode
Hardware standby input time
t
HSTL
HST
4 t
CP
ns
Under normal operation
CLK
t
CYC
2.4 V
2.4 V
0.8 V
t
CHCL