LM3407_09 Datasheet, PDF (2/16 Pages) National Semiconductor (TI) – 350 mA, Constant Current Output Floating Buck Switching Converter for High Power LEDs

Connection Diagram
Top View
8-Lead Plastic eMSOP-8 Package
Mini SOIC Exp Pad (MUY08A)
30046602
Ordering Information
Order Number
LM3407MY
LM3407MYX
Package Type
eMSOP-8
NSC Package Drawing
MUY08A
Supplied As
1000 Units on Tape and Reel
3500 Units on Tape and Reel
Pin Descriptions
Pin(s)
1
2
3
4
5
6
7
8
EP
Name
ISNS
DIM
EN
FS
VIN
VCC
GND
LX
GND
Description
Application Information
LED Current Sense pin Connect resistor R_ISNS from this pin to ground for LED current sensing. The current
sensing resistor should be placed close to this pin.
PWM Dimming Input pin Applying logic level PWM signal to this pin controls the average brightness of the
LED string.
Device Enable pin
Applying logic high to this pin or leaving this pin open enables the switcher. When
this pin is pulled low, the switcher is disabled and will enter low power shutdown
mode.
Switching Frequency Connect resistor R_FS from this pin to ground to set the switching frequency.
Setting pin
Input Voltage pin The input voltage should be in the range of 4.5V to 30V.
Internal Regulator
Output pin
This output pin should be bypassed by a ceramic capacitor with a minimum value
of 1µF. High quality X5R or X7R ceramic capacitor is recommended.
Device Ground pin This pin should be connected to the system ground.
Drain of N-MOSFET Connect this pin to the output inductor and anode of the Schottky diode.
Switch
Thermal Pad
The bottom pad should be connected to ground. For good thermal performance,
place 4 to 6 thermal vias from EP to bottom layer PCB ground plane.
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