LM3409MYX National Semiconductor Corporation, LM3409MYX Datasheet - Page 19
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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
3. AVERAGE LED CURRENT
Determine I
Assume V
The closest 1% tolerance resistor is 0.1 Ω therefore the I
is:
The chosen component from step 3 is:
4. OUTPUT CAPACITANCE
No output capacitance is necessary.
5. INPUT CAPACITANCE
Determine t
Solve for C
Choose C
Determine I
The chosen components from step 5 are:
IN
ADJ
IN-MIN
:
L-MAX
ON
IN-RMS
= 1.24V and solve for R
:
:
:
:
SNS
:
LED
19
6. PFET
Determine minimum Q1 voltage rating and current rating:
A 100V, 3.8A 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 100V, 3A diode is chosen with V
P
The chosen component from step 7 is:
D
:
T-RMS
and P
T
:
D
DS-ON
= 750mV. Determine
= 190mΩ and Q
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