ltc3490 Linear Technology Corporation, ltc3490 Datasheet - Page 9

• Manufacturer Part Number: ltc3490
• Description: Single Cell 350ma Led Driver
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
Red Luxeon LEDs
The red, red-orange and amber Luxeon LEDs have a lower
forward voltage than the white, blue and green LEDs. Since
the LTC3490 internal circuitry is powered from the output,
it requires a minimum LED voltage of 2.5V for reliable
operation. The minimum forward voltage on the red LEDs
TYPICAL APPLICATIO S
U
U
1 NiMH OR
ALKALINE
2 NiMH OR
ALKALINE
CELL
CELLS
+
U
W
+
+
ON/OFF
1µF
1M
2-Cell Adjustable Amplitude LED Driver
1M
U
ON/OFF
Soft Turn-Off LED Driver
V
CTRL/SHDN
CELLS
V
CTRL/SHDN
CELLS
IN
IN
LTC3490
LTC3490
3.3µH
3.3µH
GND
GND
LOBAT
LOBAT
is only 2.31V. The LTC3490 requires an additional 190mV
for proper operation. In non-dimming applications, this can
be accomplished with a 0.6Ω resistor in series with the
LED. The resistor voltage drops too low in dimming appli-
cations, so a Schottky diode is recommended to keep
sufficient voltage at the output at lower currents.
CAP
LED
CAP
LED
SW
SW
350mA
LUMILEDS
LUXEON
LXHL-BW02
LUMILEDS
LUXEON
LXHL-BW02
4.7µF
4.7µF
3490 TA03
3490 TA04
LTC3490
3490fa
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