AIC2858F Datasheet, PDF (7/11 Pages) Analog Intergrations Corporation – 3A 23V Synchronous Step-Down Converter

AIC2858F
 ^{PIN DESCRIPTIONS}
Pin 1: BS:
Pin 2: IN:
Pin 3: SW:
Pin 4:GND:
High Side Gate Drive Boost Input.
BS supplies the drive for the high-
side N-Channel MOSFET switch.
Connect a 10nF or greater capai-
tor 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 4.75 to 23V power
source. By pass IN to GND with a
suitably large capacitor to elimi-
nate 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 switch to the
output load. Note that a capacitor
is required from SW to BS to
power the high-side switch.
Ground. Connect the exposed
pad on backside to Pin 4.
Pin 5: FB:
Feedback Input. FB senses the
output voltage to regulate that
voltage. Drive feedback with a
resistive voltage divider from the
output voltage.
Pin 6: COMP:
Compensation Node. COMP is
used to compensate the regula-
tion control loop. Connect a se-
ries RC network form COMP to
GND to compensate the regula-
tion control loop. In some cases,
an additional capacitor from
COMP to GND is required.
Pin 7: EN:
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.
For automatic strat-up, attach to
IN with a 100k pull up resistor.
Pin 8: SS:
Soft Star Control Input. SS con-
trols the soft star period. Connect
a capacitor from SS to GND to
set the soft-star period. A 0.1F
capacitor sets the soft-star period
to 15ms.
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