LM2678-3.3 NSC [National Semiconductor], LM2678-3.3 Datasheet - Page 15

• Manufacturer Part Number: LM2678-3.3
• Description: SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator
• Manufacturer: NSC [National Semiconductor]

Application Hints
Step 5: An input capacitor for this example will require at
least a 35V WV rating with an rms current rating of 1.75A
(1/2 Iout max). From Table 2 it can be seen that C12, a
33µF/35V capacitor from Sprague, has the highest voltage/
current rating of the surface mount components and that two
of these capacitor in parallel will be adquate.
Step 6: From Table 5 a 5A or more Schottky diode must be
selected. For surface mount diodes with a margin of safety
on the voltage rating one of two diodes can be used:
(Continued)
15
MBRD1545CT
6TQ045S
Step 7: A 0.01µF capacitor will be used for Cboost.
LLP PACKAGE DEVICES
The LM2678 is offered in the 14 lead LLP surface mount
package to allow for a significantly decreased footprint with
equivalent power dissipation compared to the TO-263. For
details on mounting and soldering specifications, refer to
Application Note AN-1187.
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