LM3502ITL-16/NOPB National Semiconductor, LM3502ITL-16/NOPB Datasheet - Page 13
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LM3502ITL-16/NOPB
Manufacturer Part Number
LM3502ITL-16/NOPB
Description
IC LED DRVR WHT BCKLT 10MICROSMD
Manufacturer
National Semiconductor
Series
PowerWise®r
Type
Backlight, White LEDr
Datasheet
1.LM3502SQ-35NOPB.pdf
(18 pages)
Specifications of LM3502ITL-16/NOPB
Topology
PWM, Step-Up (Boost)
Number Of Outputs
2
Internal Driver
Yes
Type - Primary
Backlight
Type - Secondary
White LED
Frequency
800kHz ~ 1.2MHz
Voltage - Supply
2.5 V ~ 5.5 V
Voltage - Output
15 V ~ 15.5 V
Mounting Type
Surface Mount
Package / Case
10-MicroSMD
Operating Temperature
-40°C ~ 85°C
Current - Output / Channel
400mA
Internal Switch(s)
Yes
Efficiency
80%
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
LM3502ITL-16
LM3502ITL-16TR
LM3502ITL-16TR
Application Information
WHITE LED CURRENT SETTING
The LED current is set using the following equation:
I
V
R1:
WHITE LED DIMMING
For dimming the white LED string with a pulse-width-
modulated (PWM) signal on the Cntrl pin, care must taken to
balance the tradeoffs between audible noise and white LED
If V
LED
Fb
: Feedback Pin Voltage. V
OUT2
: White LED Current.
Currrent Setting Resistor.
is not used , En2 must be grounded
20131730
Fb
= 0.25V, Typical.
FIGURE 5.
13
brightness control. For best PWM duty cycle vs. white LED
current linearity, the PWM frequency should be between
200Hz and 500Hz. Other PWM frequencies can be used, but
the linearity over input voltage and duty cycle variation will
not be as good as what the 200Hz to 500Hz PWM frequency
spectrum provides. To minimize audible noise interference, it
is recommended that a output capacitor with minimal sus-
ceptibility to piezoelectric induced stresses be used for the
particular applications that require minimal or no audible
noise interference.
20131735
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