S-8355 Seiko Instruments, S-8355 Datasheet - Page 32

• Manufacturer Part Number: S-8355
• Description: (S-8355 - S-8358) PWM/PFM SWITCHING CONTROL STEP-UP SWITCHING REGULATOR
• Manufacturer: Seiko Instruments

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STEP-UP, SUPER-SMALL PACKAGE, 600 kHz, PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8355/56/57/58 Series
5. V
The E, G, J, K, L, M, P and Q types provides separate internal circuit power supply (VDD pin) and output voltage
setting pin (VOUT pin) in the IC, making it ideal for the following applications.
Choose the products in the Table 29 according to the applications (1) or (2) above.
Cautions 1. This IC starts a step-up operation at V
DD
Connection to VDD pin
Output Voltage (V
/ V
(1) When changing the output voltage with external resistance.
(2) When outputting a high voltage such as +15 V or +20 V.
OUT
S-835xx18
S-835xx50
Separate Type (For E, G, J, K, L, M, P and Q Types)
2. Choose external resistors R
3. Attach a capacitor (C
voltage and frequency of the oscillator. (Input a voltage of 1.8 V or more at the VDD pin for all
products with a setting less than 1.9 V.) An input voltage of 1.8 V or more at the VDD pin allows
connection of the VDD pin to either the input voltage VIN pin or output VOUT pin.
is impedance between the VOUT pin and VSS pin in the IC chip. The internal resistance between
the VOUT pin and VSS pin is as follows :
(1) S-835xx18 : 2.1 to 14.8 M Ω
(2) S-835xx20 : 1.4 to 14.8 M Ω
(3) S-835xx30 : 1.4 to 14.2 M Ω
(4) S-835xx50 : 1.4 to 12.1 M Ω
oscillation of the output voltage occurs. Calculate C
C
C
[ ]
F
CC
=
)
2
•
π
1.8 V ≤ V
•
R
V
A
1
IN
•
Yes
or V
20
−
C
CC
) in parallel to the R
kHz
CC
< 5 V
Table 29
Seiko Instruments Inc.
A
and R
5 V ≤ V
Yes
Yes
V
B
IN
so as to not affect the output voltage, considering that there
DD
CC
= 0.8 V, but set 1.8 ≤ V
A
resistance when an unstable event such as
Application circuit 1 (Figure 26)
Application circuit 1 (Figure 26)
Reference Circuit
C
using the following equation :
−
DD
≤ 10 V to stabilize the output
Rev.6.6
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