LM3404FSTDIMEV National Semiconductor, LM3404FSTDIMEV Datasheet - Page 25

• Manufacturer Part Number: LM3404FSTDIMEV
• Description: BOARD, EVAL, FAST DIMMING, LM3404
• Manufacturer: National Semiconductor

Specifications of LM3404FSTDIMEV

• Kit Contents: LM3404FSTDIM Assembled Evaluation Board, LM3404 Datasheet, Application Note
• Svhc: No SVHC (15-Dec-2010)
• Kit Features: Designed To Drive A Series String Of High Power, High Brightness

routed with a short, thick shape, preferably on the component
side of the PCB. Multiple vias in parallel should be used right
at the pad of the input capacitor to connect the component
side shapes to the ground plane. A second pulsating current
loop that is often ignored is the gate drive loop formed by the
SW and BOOT pins and capacitor C
at the EMI it generates, keep C
pins.
CURRENT SENSING
The CS pin is a high-impedance input, and the loop created
by R
as small as possible to maximize noise rejection. R
SNS
, R
Z
(if used), the CS pin and ground should be made
B
close to the SW and BOOT
B
. To minimize this loop
SNS
should
25
therefore be placed as close as possible to the CS and GND
pins of the IC.
REMOTE LED ARRAYS
In some applications the LED or LED array can be far away
(several inches or more) from the LM3404/04HV, or on a sep-
arate PCB connected by a wiring harness. When an output
capacitor is used and the LED array is large or separated from
the rest of the converter, the output capacitor should be
placed close to the LEDs to reduce the effects of parasitic
inductance on the AC impedance of the capacitor. The current
sense resistor should remain on the same PCB, close to the
LM3404/04HV.
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