LM3409HVMYX/NOPB National Semiconductor, LM3409HVMYX/NOPB Datasheet - Page 18

• Manufacturer Part Number: LM3409HVMYX/NOPB
• Description: IC LED DRIVR HIGH BRIGHT 10-MSOP
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: HBLED Driverr

Specifications of LM3409HVMYX/NOPB

• Constant Current: Yes
• Topology: PWM, Step-Down (Buck)
• Number Of Outputs: 1
• Internal Driver: No
• Type - Primary: Automotive
• Type - Secondary: High Brightness LED (HBLED)
• Voltage - Supply: 6 V ~ 75 V
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP Exposed Pad, 10-HMSOP, 10-eMSOP
• Operating Temperature: -40°C ~ 125°C
• Internal Switch(s): Yes
• Efficiency: 97%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Frequency: -
• Current - Output / Channel: -
• Other names: LM3409HVMYX

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Design Example #1
EN PIN PWM DIMMING APPLICATION FOR 10 LEDS
SPECIFICATIONS
f
V
V
I
Δi
Δv
V
η = 0.95
1. NOMINAL SWITCHING FREQUENCY
Assume C
The closest 1% tolerance resistor is 24.9 kΩ therefore the
actual t
SW
LED
IN
O
TURN-ON
LED-PP
IN-PP
= 35V
= 48V; V
= 525kHz
= 2A
OFF
= 1.44V
= Δi
= 10V; V
OFF
and target f
IN-MAX
L-PP
= 470pF and η = 0.95. Solve for R
= 1A
HYS
= 75V
= 1.1V
SW
are:
OFF
:
18
The chosen components from step 1 are:
2. INDUCTOR RIPPLE CURRENT
Solve for L1:
The closest standard inductor value is 15 µH therefore the
actual Δi
The chosen component from step 2 is:
L-PP
is:
30085618