Datasheet

LM2673

SNVS030N –APRIL 2000–REVISED APRIL 2013

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Step 4: Use Table 12 or Table 13 to determine an output capacitor. With a 14.8V output the 12.5 to 15V row is

used and with a 68μH inductor there are three surface mount output capacitor solutions. Table 3 or Table 4

provide the actual capacitor characteristics based on the C Code number. Any of the following choices can be

used:

1 x 33μF/20V AVX TPS (code C6)

1 x 47μF/20V Sprague 594 (code C8)

1 x 47μF/20V Kemet T495 (code C8)

NOTE

When using the adjustable device in low voltage applications (less than 3V output), if the

nomograph, Figure 21, selects an inductance of 22μH or less, Table 12 and Table 13 do

not provide an output capacitor solution. With these conditions the number of output

capacitors required for stable operation becomes impractical. It is recommended to use

either a 33μH or 47μH inductor and the output capacitors from Table 12 or Table 13.

Step 5: An input capacitor for this example will require at least a 35V WV rating with an rms current rating of 1A

(1/2 Iout max). From Table 3 or Table 4 it can be seen that C12, a 33μF/35V capacitor from Sprague, has the

required voltage/current rating of the surface mount components.

Step 6: From Table 10 a 3A Schottky diode must be selected. For surface mount diodes with a margin of safety

on the voltage rating one of five diodes can be used:

SK34

30BQ040

30WQ04F

MBRS340

MBRD340

Step 7: A 0.01μF capacitor will be used for Cboost.

The softstart pin will be left open circuited.

Step 8: Determine a value for R

ADJ

to provide a peak switch current limit of at least 2A plus 50% or 3A.

(8)

Use a value of 12.4KΩ.

VSON PACKAGE DEVICES

The LM2673 is offered in the 14 lead VSON surface mount package to allow for a significantly decreased

footprint with equivalent power dissipation compared to the DDPAK. For details on mounting and soldering

specifications, refer to Application Note AN-1187 at

www.ti.com/lsds/ti/analog/powermanagement/power_portal.page.

Product Folder Links: LM2673