TAMURA EPM Series, Application Notes, Page: 10 / 19

EPM Series Application Notes
Rev.3.1 May, 2013 TAMURA CORPORATION 9 / 17
CR mode CC mode
EPM0310SJ 5600uFmax 3300uFmax
EPM0510SJ 4700uFmax 3000uFmax
EPM1205SK 750uFmax 470uFmax
EPM1205SJ 1500uFmax 1000uFmax
EPM1210SJ/SK 2400uFmax 1300uFmax
EPM1505SJ/SK 1000uFmax 680uFmax
EPM1510SJ/SK 2700uFmax 1800uFmax
EPM2405SJ/SK 680uFmax 470uFmax
Model
Recommendation capacitance
The ripple current of an electrolytic capacitor is a triangle wave high frequencycurrent with the input current
(DC current) made the average value. Ripple current is calculated as follows:
2 2
Ich Idis Iripple
+ =
1.10 Output smoothing electrolytic capacitor（C201)
The output smoothing electrolytic capacitor has a large effect on the characteristics and life of the product.
Select the electrolytic capacitor by paying attention to the following:
①Install the capacitor very close to the module (M101) and use a wide pattern to connect M101 .
②Use an electrolytic capacitor with good frequency characteristics and low impedance.
Output ripple and noise and rise time may be affected depending on the ESR and ESL and wiring impedance of
the capacitor.
③If the capacitance is too large, the overcurrent protection function may operate and the rise may be faulty at
startup. A recommended value is shown in the following table.
Please ask us, when the capacity more than the following table is required.
④Since abnormal oscillation may occur by large phase delay if a capacitor with a very small ESR such as a
tantalum capacitor or multilayer ceramic capacitor is used, use an electrolytic capacitor.
Discharging current (Idis)
Charging current (Ich)
Triangle wave high frequency current flows.
Make the wiring wide and short.