ADP2389/ADP2390

Data Sheet

The ADP2389/ADP2390 use a transconductance amplifier for the

error amplifier and to compensate the system. Figure 31 shows

the simplified, peak current mode control, small signal circuit.

Figure 31. Simplified Peak Current Mode Control, Small Signal Circuit

The closed-loop transfer equation is as follows:

)

(

1

1

–

)

(

s

G

s

C

C

C

C

R

s

s

C

R

C

C

g

R

R

R

s

T

VD

P

C

CP

C

C

C

C

CP

C

m

TOP

BOT

BOT

V

×













×

+

×

×

+

×

×

×

+

×

+

×

+

=

The following design guideline shows how to select the

capacitor applications.

VI

m

C

OUT

OUT

C

A

g

f

C

V

R

×

×

×

×

×

×

=

V

6

.

0

()

ESR

OUT

C

C

R R

C

C

R

+×

=

ESR of the output capacitor.

ESR

OUT

CP

C

RC

C

R

×

=

R

+

–

–

+

Rev. 0 | Page 16 of 23