MB3881 Datasheet, PDF (21/40 Pages) Fujitsu Component Limited. – 8-ch DC/DC Converter IC with Synchronous Rectifier for Voltage Step-up and Step-down

MB3881
(2) Setting Soft Start
• Channel-8 soft start
Channel 8 can be soft-started by connecting a capacitor between the DTC8 terminal (pin 3) and GND. The soft
start time depends on the input voltage and load current.
• Channel 1 to 4 and channel 7 soft start
Soft start time
ts[s] =: 1.25 × Cs[µF]
Note : The short-circuit detection function remains working even during soft start operation of channels 1 to 4 and 7.
• Channel-5, 6 soft start
Channel 5 can be soft-started by connecting a capacitor between the +IN5 terminal (pin 22) and GND.
Channel 6, like channel 5, can be soft-started by connecting a capacitor between the +IN6 terminal (pin 16) and
GND.
s SETTING THE OSCILLATION FREQUENCY
The oscillation frequency can be set by connecting the timing capacitor (CT) to the CT terminal (pin 34) and the
timing resistor (RT) to the RT terminal (pin 33).
Oscillation frequency
fOSC
(kHz)
=:
550000
CT (pF) × RT (kΩ)
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