FR9886 Ver la hoja de datos (PDF) - Unspecified
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componentes Descripción
Fabricante
FR9886 Datasheet PDF : 14 Pages
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fitipower integrated technology lnc.
Functional Pin Description
FR9886
85T
I/O Pin Name Pin No.
Pin Function
I
FB
I
VIN
I
SHDN
I
GND
5
Voltage Feedback Input Pin. Connect FB and VOUT with a resistive voltage
divider. This IC senses feedback voltage via FB and regulates it at 0.925V.
2
Power Supply Input Pin. Drive this pin by 4.5V to 23V voltage to power on the
chip.
7
Enable Input Pin. This pin provides a digital control to turn the converter on or
off. Connect VIN with a 100KΩ resistor for self-startup.
4 Ground Pin. Connect this pin to exposed pad.
O
LX
O
SS
O BOOST
3
Power Switching Output. It is the output pin of internal high side NMOS which
is the switching to supply power.
8
Soft-Start Pin. This pin controls the soft-start period. Connect a capacitor
from SS to GND to set the soft start period.
High Side Gate Drive Boost Pin. A 10nF or greater capacitor must be
1 connected from this pin to LX. It can boost the gate drive to fully turn on the
internal high side NMOS.
O
NC
6 No connection. Keeps this pin floating.
Block Diagram
VIN
SHDN
1M
UVLO
&
POR
6µ A
FB
SS
0.925V
ISEN
Internal
Regulator
Oscillator
VCC
OTP
OVP
Current
Comp
S
R
OTP
OVP
UVLO
PWM
Control
Current
Limit
VCC
Driver
Logic
BOOST
High-Side
MOSFET
LX
Low-Side
MOSFET
GND
Figure 4. Block Diagram of FR9886
FR9886- 1.0-APR-2011
3
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