SNVS124F November 1999 – April 2021 LM2596
For additional information, see section on output capacitors in Table 9-3.
From Table 9-3, 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 9-3.
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 9-2 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.