LM3429BKBSTEVAL/NOPB National Semiconductor, LM3429BKBSTEVAL/NOPB Datasheet - Page 20
![BOARD EVAL FOR BUCK-BOOST LM3429](/photos/28/39/283985/lm3429bkbsteval_nopb_sml.jpg)
LM3429BKBSTEVAL/NOPB
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
*LM3429BKBSTEVAL/NOPB
LM3429BKBSTEVAL
www.national.com
A high frequency compensation pole (ω
attenuate switching noise and provide better gain margin. As-
suming R
value of the pole and the RHP zero of the system (shown as
a maximizing function):
The total system loop gain (T) can then be written as:
Buck
Boost and Buck-boost
8. INPUT CAPACITANCE
Set the nominal input voltage ripple (Δv
the required capacitance (C
Buck
Boost
Buck-boost
Use D
solving for C
solving for C
The minimum allowable RMS input current rating (I
can be approximated:
Buck
Boost
MAX
FS
to set the worst case input voltage ripple, when
= 10Ω, C
IN
IN
in a buck-boost regulator and D
in a buck regulator.
FS
is calculated according to the higher
IN
):
IN-PP
P3
) can be used to
) by solving for
MID
= 0.5 when
CIN-RMS
)
20
Buck-boost
9. NFET
The NFET voltage rating should be at least 15% higher than
the maximum NFET drain-to-source voltage (V
Buck
Boost
Buck-boost
The current rating should be at least 10% higher than the
maximum average NFET current (I
Buck
Boost and Buck-boost
Approximate the nominal RMS transistor current (I
Buck
Boost and Buck-boost
Given an NFET with on-resistance (R
nominal power dissipation (P
10. DIODE
The Schottky diode voltage rating should be at least 15%
higher than the maximum blocking voltage (V
Buck
Boost
Buck-boost
T
):
T-MAX
DS-ON
):
), solve for the
RD-MAX
T-MAX
T-RMS
):
):
) :