LM3409MYX National Semiconductor Corporation, LM3409MYX Datasheet - Page 22
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LM3409MYX
Manufacturer Part Number
LM3409MYX
Description
Pfet Buck Controller For High Power Led Drives
Manufacturer
National Semiconductor Corporation
Datasheet
1.LM3409MYX.pdf
(30 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM3409MYX
Manufacturer:
NS/国半
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
=
: