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BD9102FVM BD9104FVM

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TSZ22111･14･001

TSZ02201-0J3J0AJ00340-1-2

24.Oct.2013 Rev.003





OUT

OUT

LIMIT

O

V

I

I

C



t

(a) Current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which decreases

efficiency.

The inductor must be selected allowing sufficient margin with which the peak current may not exceed its current

rating.

(b) Select an inductor with low resistance component (such as DCR and ACR) to minimize dissipation in the inductor

for better efficiency.

Since the output rise time is designed to fall within the soft-start time, the capacitance of output capacitor should be

determined with consideration on the requirements of equation (5):





 

F

m

C

O



364

3

.

3

8

.

0

2

1









Rating of the capacitor should be determined to allow a sufficient margin against output voltage. A 10 μF to 100 μF

ceramic capacitor is recommended.

A low ESR 10μF/10V ceramic capacitor is recommended to reduce ESR dissipation of input capacitor for better

efficiency.

Output capacitor should be selected with the consideration of stability region and

equivalent series resistance required to minimize the ripple voltage.

Output ripple voltage is determined by the equation (4):

* Rating of the capacitor should be determined allowing sufficient margin

against output voltage. Less ESR allows reduction in output ripple voltage.

Input capacitor must be a low ESR capacitor with capacitance sufficient to cope

with high ripple current to prevent high transient voltage. The ripple current IRMS

is given by the equation (6):

Figure 40. Output Capacitor

Where:

Figure 41. Input Capacitor

L

ESR

L





 

H

M

L





7

.

4

675

.

4

1

5

24

.

0

3

.

3

3

.

3

5















・・・

(4)

 

V

ESR

I

V

L

OUT









・・・

(6)



A

CC

V

OUT

V

CC

V

CC

V

OUT

I

RMS

I







2

I

,

V

the

twice

is

V

When

OUT

OUT

CC









RMS

A

RMS

I

46

.

0

5

3

.

3

5

5

8

.

0









・・・

(5)

Where:

ESR is the Equivalent series resistance of output capacitor.