SNVS124E November 1999 – February 2020 LM2596
For additional information, see section on output capacitors in Table 3.
From Table 3, locate the 5-V output voltage section. In the load current column, choose the load current line that is closest to the current required for the application; for this example, use the 3-A line. In the maximum input voltage column, select the line that covers the input voltage required for the application; in this example, use the 15-V line. The rest of the line shows recommended inductors and capacitors that will provide the best overall performance.
|THROUGH-HOLE ELECTROLYTIC||SURFACE-MOUNT TANTALUM|
The capacitor list contains both through-hole electrolytic and surface-mount tantalum capacitors from four different capacitor manufacturers. TI recommends that both the manufacturers and the manufacturer's series that are listed in Table 3.
In this example aluminum electrolytic capacitors from several different manufacturers are available with the range of ESR numbers required.
For a 5-V output, a capacitor voltage rating of at least 7.5 V is required. But even a low ESR, switching grade, 220-μF, 10-V aluminum electrolytic capacitor would exhibit approximately 225 mΩ of ESR (see Figure 24 for the ESR versus voltage rating). This amount of ESR would result in relatively high output ripple voltage. To reduce the ripple to 1% or less of the output voltage, a capacitor with a higher value or with a higher voltage rating (lower ESR) must be selected. A 16-V or 25-V capacitor will reduce the ripple voltage by approximately half.