UM5482S8 Datasheet, PDF (2/6 Pages) Union Semiconductor, Inc. – Programmable Soft-Start

UM5482S8 Initial Spec
Pin Description
Pin
Number
1
2
3
4
5
6
7
8
Symbol
BS
IN
SW
GND
FB
COMP
EN
SS
Function
High-Side Gate Drive Boost Input. BS supplies the drive for the
high-side N-Channel MOSFET switch. Connect a 0.01μF or greater
capacitor from SW to BS to power the high side switch.
Power Input. IN supplies the power to the IC, as well as the
step-down converter switches. Drive IN with a 4.75V to 18V power
source. Bypass IN to GND with a suitably large capacitor to eliminate
noise on the input to the IC.
Power Switching Output. SW is the switching node that supplies
power to the output. Connect the output LC filter from SW to the
output load. Note that a capacitor is required from SW to BS to power
the high-side switch.
Ground.
Feedback Input. FB senses the output voltage to regulate that voltage.
Drive FB with a resistive voltage divider from the output voltage. The
feedback threshold is 0.923V.
Compensation Node. COMP is used to compensate the regulation
control loop. Connect a series RC network from COMP to GND to
compensate the regulation control loop. In some cases, an additional
capacitor from COMP to GND is required.
Enable Input. EN is a digital input that turns the regulator on or off.
Drive EN high to turn on the regulator, drive it low to turn it off. Pull
up with 100kΩ resistor for automatic startup.
Soft-Start Control Input. SS controls the soft start period. Connect a
capacitor from SS to GND to set the soft-start period. A 0.1μF
capacitor sets the soft-start period to 15ms. To disable the soft-start
feature, leave SS unconnected.
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http://www.union-ic.com Rev.03 Sep.2016
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