LM3424MH/NOPB National Semiconductor, LM3424MH/NOPB Datasheet - Page 32

• Manufacturer Part Number: LM3424MH/NOPB
• Description: IC LED DVR BUCK/BOOST 20-TSSOP
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: High Power, Constant Currentr

Specifications of LM3424MH/NOPB

• Constant Current: Yes
• Topology: Flyback, PWM, SEPIC, Step-Down (Buck), Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: No
• Type - Primary: Automotive
• Type - Secondary: High Brightness LED (HBLED)
• Frequency: 2MHz
• Voltage - Supply: 4.5 V ~ 75 V
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP Exposed Pad, 20-eTSSOP, 20-HTSSOP
• Operating Temperature: -40°C ~ 125°C
• Current - Output / Channel: 1A
• Internal Switch(s): Yes
• Efficiency: 96%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Other names: LM3424MH

www.national.com
6. OUTPUT CAPACITANCE
Solve for C
The closest capacitance totals 40 µF therefore Δi
Determine minimum allowable RMS current rating:
The chosen components from step 6 are:
7. PEAK CURRENT LIMIT
Solve for R
The closest standard resistor is 0.04 Ω therefore I
The chosen component from step 7 is:
8. SLOPE COMPENSATION
Solve for R
The chosen component from step 8 is:
O
LIM
SLP
:
:
:
LED-PP
LIM
is:
is:
32
9. LOOP COMPENSATION
ω
ω
T
To ensure stability, calculate ω
Solve for C
To attenuate switching noise, calculate ω
Assume R
The chosen components from step 9 are:
U0
P1
Z1
is approximated:
is approximated:
is approximated:
FS
CMP
= 10Ω and solve for C
:
P2
:
FS
:
P3
: