LM3429BKBSTEVAL/NOPB National Semiconductor, LM3429BKBSTEVAL/NOPB Datasheet - Page 6

• Manufacturer Part Number: LM3429BKBSTEVAL/NOPB
• Description: BOARD EVAL FOR BUCK-BOOST LM3429
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3429BKBSTEVAL/NOPB

• Current - Output / Channel: 1A
• Outputs And Type: 1, Non-Isolated
• Features: Dimmable
• Voltage - Input: 10 ~ 70 V
• Utilized Ic / Part: LM3429
• Core Chip: LM3429
• Topology: Buck-Boost
• No. Of Outputs: 1
• Dimming Control Type: PWM / Analog
• Development Tool Type: Hardware - Eval/Demo Board
• Mcu Supported Families: LM3429 Family
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Voltage - Output: -
• Other names: *LM3429BKBSTEVAL; *LM3429BKBSTEVAL/NOPB; LM3429BKBSTEVAL

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5. OUTPUT CAPACITANCE
Solve for C
A total value of 6.6 µF (using 3 2.2 µF X7R ceramic capaci-
tors) is chosen therefore the actual Δi
Determine minimum allowable RMS current rating:
The chosen components from step 5 are:
6. PEAK CURRENT LIMIT
Solve for R6:
The closest standard resistor is 0.05 Ω therefore I
The chosen component from step 6 is:
7. LOOP COMPENSATION
ω
ω
P1
Z1
is approximated:
is approximated:
O
:
LED-PP
is:
LIM
is:
6
T
To ensure stability, calculate ω
Solve for C8:
Since PWM dimming can be evaluated with this board, a
much larger compensation capacitor C8 = 1.0 µF is chosen.
To attenuate switching noise, calculate ω
Assume R20 = 10Ω and solve for C12:
The chosen components from step 7 are:
8. INPUT CAPACITANCE
Solve for the minimum C
To minimize power supply interaction a 3x larger capacitance
of approximately 20 µF is used, therefore the actual Δv
is much lower. Since high voltage ceramic capacitor selection
is limited, four 4.7 µF X7R capacitors are chosen.
Determine minimum allowable RMS current rating:
The chosen components from step 8 are:
U0
is approximated:
IN
:
P2
:
P3
:
IN-PP