S1F78100Y2A Epson Electronics America, Inc., S1F78100Y2A Datasheet - Page 24

• Manufacturer Part Number: S1F78100Y2A
• Description: High Precision Voltage Regulators
• Manufacturer: Epson Electronics America, Inc.

FUNCTIONAL DESCRIPTIONS
CR Oscillator
S1F76600 has a built-in CR oscillator as the internal os-
cillator, and an external oscillation resistor R
nected between the pins OSC1 and OSC2 before opera-
tion.
Note 1
Since the oscillation frequency varies with wiring ca-
pacitance, make the cables between the terminals OSC1
and OSC2 and R
When setting the external resistor R
able for f
from characteristics graph (9) and (10). The relations
between R
expressed approximately with the following formula as
S1F70000 Series
Technical Manual
(13) Multiplication efficiency/input current
100
90
80
70
60
50
40
30
20
10
0
0
OSC
Ta = 25 C
V
OSC
I
1
= –2.0V
that brings about the maximum efficiency
and f
OSC1
OSC2
2
vs. Output current
OSC
3
OSC
as short as possible.
4
in characteristics graph (1) are
I
O
[mA]
5
6
(Note 1)
OSC
7
R
OSC
, find R
Peff
8
I
I
9 10
OSC
OSC
is con-
40
36
32
28
24
20
16
12
8
4
0
suit-
EPSON
far as the
straight portion (500k < R
(A : Constant, When GND is 0V and V
approximately 2.0 10
So, the R
(Recommended oscillation frequency : 10kHz to 30kHz
(R
When the external clock operates, make the pin OSC2
open as shown below and input the 50% duty of the ex-
ternal clock from the pin OSC1.
Voltage Multiplier
The voltage multiplier uses the clock signal from the
oscillator to double the input voltage. This requires two
external capacitors—a charge-pump capacitor, C1, be-
tween CAP1+ and CAP1–, and a smoothing capacitor,
C2, between V
Doubled potential levels
OSC
V
(+5V)
GND
(–5V)
V
: 2M to 680k ))
1M
I
CC
= –5 V
OSC
OSC1
OSC2
1
2
3
4
value can be obtained from this formula.
I
V
5 V
and V
DD
R
= 0 V
V
V
V
OSC
DD
I
O
= –5 V
= (2V
O
10
= 0 V
= A • (1/f
.
Open
(I/F).)
I
OSC
) = –10 V
8
7
6
5
External clock
< 2M ) is concerned:
OSC
S1F76600 Series
+
+
)
10 F
V
10 F
C2
C1
O1
DD
= –10V (2V
is 5V, A is
I
)
1–7