MB3881PFF datasheet(21/40 Pages) FUJITSU

Part #	MB3881PFF

Description	8-ch DC/DC Converter IC with Synchronous Rectifier for Voltage Step-up and Step-down

PDF	40 Pages

Scroll/Zoom	100%

Manufacturer	FUJITSU [fujitsu semiconductor]

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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)

MB3881PFF Datasheet(PDF) 21 Page - fujitsu semiconductor