The inductor and the output capacitor together provide a low-pass filter. To simplify this process, Table 9-4 outlines possible inductor and capacitor value combinations for most applications. Checked cells represent combinations that are proven for stability by simulation and lab test. Further combinations should be checked for each individual application.
Table 9-4 Matrix of Output Capacitor and Inductor CombinationsNOMINAL L [µH](2) | NOMINAL COUT [µF](3) |
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10 | 2 x 10 or 1 x 22 | 47 | 100 |
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0.24 | + | +(1) | + | |
0.33 | + | + | + | |
0.47 | | | | |
(1) This LC combination is the standard value and recommended for most applications. Other '+' marks indicate recommended filter combinations. Other values may be acceptable in some applications but should be fully tested by the user.
(2) Inductor tolerance and current derating is anticipated. The effective inductance can vary by 20% and –30%.
(3) Capacitance tolerance and bias voltage derating is anticipated. The effective capacitance can vary by 20% and –50%.