Datasheet

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LM4510
www.ti.com SNVS533C –SEPTEMBER 2007–REVISED MAY 2013
To prevent loss of regulation, ensure that the NMOS power switch current limit is greater than the worst-case
peak inductor current in the target application.
Also make sure that the inductor saturation current is greater than the peak inductor current under the worst-case
load transient, high ambient temperature and startup conditions. Refer to Table 2 for suggested inductors.
Table 2. Suggested Inductors and Their Suppliers
Model Vendor Dimensions LxWxH (mm) D.C.R (max)
DO3314-472ML COILCRAFT 3.3mm x 3.3mm x 1.4mm 320 mΩ
DO3316P-472ML COILCRAFT 12.95mm x 9.4mm x 5.4mm 18 mΩ
INPUT CAPACITOR SELECTION
Due to the presence of an inductor, the input current waveform is continuous and triangular. So the input
capacitor is less critical than output capacitor in boost applications. Typically, a 4.7 μF to 10 μF ceramic input
capacitor is recommended on the VIN pin of the IC.
I
CIN_RMS
Check
The RMS current in the input capacitor is given by the following equation:
(6)
The input capacitor should be capable of handling the RMS current.
OUTPUT CAPACITOR SELECTION
The output capacitor in a boost converter provides all the output current when the switch is closed and the
inductor is charging. As a result, it sees very large ripple currents.
A ceramic capacitor of value 4.7 μF to 10 μF is recommended at the output. If larger amounts of capacitance are
desired for improved line support and transient response, tantalum capacitors can be used.
I
COUT_RMS
Check
The RMS current in the output capacitor is given by the following equation:
(7)
The output capacitor should be capable of handling the RMS current.
The ESR and ESL of the output capacitor directly control the output ripple. Use capacitors with low ESR and ESL
at the output for high efficiency and low ripple voltage. The output capacitor also affects the soft-start time (See
SOFT-START FUNCTION AND SOFT-START CAPACITOR SELECTION). Table 3 shows suggested input and
output capacitors.
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