LM3406HVEVAL National Semiconductor, LM3406HVEVAL Datasheet - Page 17

• Manufacturer Part Number: LM3406HVEVAL
• Description: LM3406/06HV 1.5A Constant Current Buck Regulator for Driving High Power LEDs; Qty per Container: 1/
• Manufacturer: National Semiconductor

GENERAL COMMENTS REGARDING OTHER PINS
Any pin that goes “off-board” through a connector should have
series resistance of at least 1kΩ to 10kΩ in series with it to
protect it from ESD or other transients. These series resistors
limit the peak current that can flow (or cause a voltage drop)
during a transient event, thus protecting the pin and the de-
vice. Pins that are not used should not be left floating. They
should instead be tied to GND or to an appropriate voltage
through resistance.
Design Example 1
The first example circuit uses the LM3406 to create a flexible
LED driver capable of driving anywhere from one to five white
FIGURE 12. VIN Pin with Additional Input Protection
FIGURE 13. Schematic for Design Example 1
17
series-connected LEDs at a current of 1.5A ±5% from a reg-
ulated DC voltage input of 24V ±10%. In addition to the ±5%
tolerance specified for the average output current, the LED
ripple current must be controlled to 10%
or 150 mA
LED at 1.5A is 3.9V, hence the output voltage ranges from
4.1V to 19.7V, adding in the 0.2V drop for current sensing. A
complete bill of materials can be found in
of this datasheet.
P-P
. The typical forward voltage of each individual
30020369
P-P
Table 1
30020318
of the DC value,
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at the end