S-8327 Seiko, S-8327 Datasheet - Page 21

• Manufacturer Part Number: S-8327
• Description: (S-8323 / S-8327) SMALL PACKAGE PWM CONTROL STEP-UP SWITCHING REGULATOR
• Manufacturer: Seiko

SMALL PACKAGE PWM CONTROL STEP-UP SWITCHING REGULATOR
S-8323/8327 Series


20
3. Step-down DC/DC converter
Application Circuits
1. Backup Circuit
2. 5V/Backup Change
allows the backup voltage of the microcomputer to be supplied with low current consumption.
Reduces the backup battery voltage from 3 V to 1.5 V (from 2 cells to 1 cell).
The S-8323A/8327B is provided with a power OFF function, where V
The start circuit is not needed because the power supply is supplied from V
The maximum input voltage for V
DO NOT mount R
The external resistor Rb must be 60
reduction of reactive current for R
Too large value of R
of R
E
under the operating conditions.
1.5V
V
V
IN
IN
A
and R
E
lowers efficiency due to the large switching loss of the external transistor (Tr). Choose a suitable value
+
-
+
-
+
-
C
B
Voltage
Detector
IN
resistors when V
DD
E
and R
R
is 9 V.
E
ON/
OFF
V
Tr
or more and R
DD
CONT
b
R
.
b
CC
S-8323A
S-8323D
Figure 19
ON/OFF
CONT
is 2V for S-8323D20MC and 5V for S-8323D50MC.
Seiko Instruments Inc.
Figure 17
V
S-8323A
E
S
must be 6K
CONT
Figure 18
V
V
OUT
OUT
V
S
V
S
V
OUT
C
+
-
C
or less. A large value for R
OUT
R
R
DD
+
-
becomes approx. V
A
B
to the IC.
+
-
C
OUT
CE
S-RAM
V
CC
CPU
IN
E
-0.6V. This characteriistic
raises efficiency due to the
Main Power (5V)