LM3409MY/NOPB National Semiconductor, LM3409MY/NOPB Datasheet - Page 22
![IC LED DRIVR HIGH BRIGHT 10-MSOP](/photos/7/37/73786/pkg_muc10a_sml.jpg)
LM3409MY/NOPB
Manufacturer Part Number
LM3409MY/NOPB
Description
IC LED DRIVR HIGH BRIGHT 10-MSOP
Manufacturer
National Semiconductor
Series
PowerWise®r
Type
HBLED Driverr
Datasheet
1.LM3409MYNOPB.pdf
(30 pages)
Specifications of LM3409MY/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 ~ 42 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
LM3409MYTR
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM3409MY/NOPB
Manufacturer:
TI/德州仪器
Quantity:
20 000
www.national.com
3. AVERAGE LED CURRENT
Determine I
Assume V
The closest 1% tolerance resistor is 0.2 Ω therefore I
The chosen component from step 3 is:
4. OUTPUT CAPACITANCE
Assume r
Solve for C
Choose C
The chosen component from step 5 is:
5. INPUT CAPACITANCE
Determine t
Solve for C
Choose C
D
O
IN
ADJ
O-MIN
:
IN-MIN
= 2 Ω and determine Z
L-MAX
ON
:
= 1.24V and solve for R
:
:
and :
:
C
:
SNS
:
LED
is:
22
Determine I
The chosen component from step 5 is:
6. PFET
Determine minimum Q1 voltage rating and current rating:
A 70V, 5.7A PFET is chosen with R
20nC. Determine I
The chosen component from step 6 is:
7. DIODE
Determine minimum D1 voltage rating and current rating:
A 60V, 5A diode is chosen with V
The chosen component from step 7 is:
IN-RMS
:
T-RMS
and P
T
:
D
= 750mV. Determine P
DS-ON
= 190mΩ and Q
g
D
=
: