S-8365AAABA-M5T1Y2 Datasheet, PDF (25/63 Pages) Seiko Instruments Inc – PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER

STEP-UP, SUPER-SMALL PACKAGE, 1.2 MHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.2.1_01
S-8365/8366 Series
(3) Low input voltage (SOT-23-5)
L
C_b
Q1
R_{b EXT}
SD
IC internal
power supply
Triangular wave
oscillation circuit
PWM comparator
PWM control, or
PWM / PFM switching
+
control circuit
−
Error
amplifier
+
−
V_OUT
VDD
C_FB
FB
R_FB1
R_FB2
V_IN C_IN
ON/OFF
ON/OFF
circuit
Reference voltage
with soft-start circuit
VSS
C_OUT
0.1 μF
Ground point
Figure 22
Caution The above connection diagram and constant will not guarantee successful operation. Perform
thorough evaluation using an actual application to set the constants.
 Precaution
• Mount external capacitors and inductor as close as possible to the IC. Set single point ground.
• Characteristics ripple voltage and spike noise occur in IC containing switching regulators. Moreover rush current
flows at the time of a power supply injection. Because these largely depend on the inductor, the capacitor and
impedance of power supply used, fully check them using an actually mounted model.
• The 0.1 μF capacitor connected between the VDD and VSS pins is a bypass capacitor. It stabilizes the power
supply in the IC when application is used with a heavy load, and thus effectively works for stable switching
regulator operation. Allocate the bypass capacitor as close to the IC as possible, prioritized over other parts.
• Although the IC contains a static electricity protection circuit, static electricity or voltage that exceeds the limit of
the protection circuit should not be applied.
• The power dissipation of the IC greatly varies depending on the size and material of the board to be connected.
Perform sufficient evaluation using an actual application before designing.
• SII Semiconductor Corporation claims no responsibility for any disputes arising out of or in connection with any
infringement by products including this IC of patents owned by a third party.
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