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5. FUNCTIONAL DESCRIPTION
5. FUNCTIONAL DESCRIPTION
5.1 Clock Generator
S1F76540, which contains a clock generator for boosting control, requires no external parts.
The clock frequency varies depending on the FC pin level (see Table 5.1), and you can select either the low
output mode or high output mode. This results in you being able to select the clock frequency based on the load
current and value of the capacitor to be used because the boosting output impedance varies depending on the
clock frequency and the values of the external capacitors for boosting.
Mode
FC pin
name
H(V
)
Low output
DD
L(VI)
High output
(Note 1)
For the consumption current value, see 7.1 DC Characteristics Table.
(Note 2)
For information about how to define and roughly estimate the output ripple value, see 9.4.
Figure 5.1 Capacitor capacity value - output impedance characteristics diagram
4
Table 5.1 FC pin settings
Clock
Consumption
frequency
current
4.0kHz
IOP (Note 1)
（Typ.）
16.0kHz
IOP (Note 1)
（Typ.）
550
Quadruple boosting Ta=25°C Io=10mA
C
=C
500
I
(Tantalum capacitor)
450
VI=-3V FC=Low
400
VI=-5V FC=Low
350
VI=-3V FC=High
300
250
200
150
1
EPSON
Selection judgment characteristics
Output ripple
VRP (Note 2)
VRP (Note 2)
=C
=C
=C
1
2
3
O
VI=-5V FC=High
10
C[µF]
S1F76540M0C Series Technical Manual
Output
Capacitor
impedance
capacity
See Figure.5.1
See Figure.5.1
See Figure.5.1
See Figure.5.1
100
(Rev.1.1)
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