LM3434SQX National Semiconductor Corporation, LM3434SQX Datasheet - Page 10
LM3434SQX
Manufacturer Part Number
LM3434SQX
Description
Lm3434 Common Anode Capable High Brightness Led Driver With High Frequency Dimming
Manufacturer
National Semiconductor Corporation
Datasheet
1.LM3434SQX.pdf
(14 pages)
LAYOUT CONSIDERATIONS
The LM3434 is a high performance current driver so attention
to layout details is critical to obtain maximum performance.
The most important PCB board design consideration is mini-
mizing the loop comprised by the main FET, synchronous
FET, and their associated decoupling capacitor(s). Place the
V
bypass capacitor as near as possible to the LM3434.
CC
Place the PWM dimming/shunt FET as close to the LED as
possible. A ground plane should be used for power distribu-
tion to the power FETs. Use a star ground between the
LM3434 circuitry, the synchronous FET, and the decoupling
capacitor(s). The EP contact on the underside of the package
must be connected to V
. The two lines connecting the sense
EE
resistor to CSN and CSP must be routed as a differential pair
directly from the resistor. A Kelvin connection is recommend-
ed. It is good practice to route the DIMO/DIMR, HS/HO, and
LO/LS lines as differential pairs. The most important PCB
board design consideration is minimizing the loop comprised
by the main FET, synchronous FET, and their associated de-
coupling capacitor(s). Optimally this loop should be orthogo-
nal to the ground plane.
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