LP3311S Datasheet, PDF (2/7 Pages) Lowpower Semiconductor inc – 1MHz Fixed-Frequency PWM Operation

Preliminary Datasheet
LP3311S
Functional pin description
SOT-23-6 Pin Name Pin Function
1
SW
Switch Pin. Connect this Pin to inductor and catch diode. Minimize the
track area to reduce EMI.
2
GND
Ground Pin
3
FB
4
EN
Feedback Reference Voltage Pin. Series connect a resistor between
WLED and ground as a current sense. Sense the current feedback
voltage to set the current rating.
Chip Enable (Active High). Voltage sensing input to trigger the function of
over voltage protection. Note that this pin is high impedance. There
should be a pull low 100kΩ resistor connected to GND when the control
signal is floating.
5
OVP
Over voltage pin.
6
Vin
Supply Input Voltage Pin. Bypass 1uF capacitor to GND to reduce the
input noise.
Function Block Diagram
IN
OUT
SW
200 mV
OTA
FB
Soft
start
PW M_ COM P.
Over
voltage
PWM
R
Q
S
∑
RS
EN
4mS
DELAY
SLOPE
ENABLE
1MHz
OBCILLATOR
GND
LP3311s – 02 Version 2.0 Datasheet May.-2013
www.lowpowersemi.com
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