LM3402MRX National Semiconductor, LM3402MRX Datasheet - Page 19

• Manufacturer Part Number: LM3402MRX
• Description: LM3402/LM3402HV 0.5A Constant Current Buck Regulator for Driving High Power LEDs; Package: PSOP; No of Pins: 8; Qty per Container: 2500; Container: Reel
• Manufacturer: National Semiconductor

tance (similar to an under-damped LC tank circuit) and
causes voltages at the VIN pin to rise well in excess of both
V
by the input TVS. If the resonating voltage at the VIN pin ex-
ceeds the 80V breakdown voltage of the ESD structure, the
ESD structure will activate and then “snap-back” to a lower
voltage due to its inherent design. If this lower snap-back
voltage is less than the applied nominal V
nificant current will flow through the ESD structure resulting
in the IC being damaged.
IN
and the voltage at the module input connector as clamped
FIGURE 10. VIN Pin with Typical Input Protection
IN
voltage, then sig-
19
An additional TVS or small zener diode should be placed as
close as possible to the VIN pins of each IC on the board, in
parallel with the input capacitor as shown in
nor amount of series resistance in the input line would also
help, but would lower overall conversion efficiency. For this
reason, NTC resistors are often used as inrush limiters in-
stead.
20192162
Figure
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11. A mi-