Datasheet

C
HF
5 m: x 724 µF x 10 nF
27.4 k: x 10 nF - 5 m: x 724 µF
=
= 134 pF
C
HF
R
ESR
x C
OUT
x C
COMP
R
COMP
x C
COMP
- R
ESR
x C
OUT
=
[F]
C
COMP
27.4 k:
=
x 724 µF
3.3V
9A
= 10 nF
C
COMP
R
LOAD
x C
OUT
R
COMP
=
[F]
R
COMP
= 2Sx 8 m: x 10 x 724 µF x 3.24 k: x 23 kHz = 27.1 k:
LM25117
LM25117-Q1
SNVS714E –APRIL 2011–REVISED MARCH 2013 www.ti.com
(52)
The standard value of 27.4kΩ was selected for R
COMP
STEP3: Determine C
COMP
to cancel load pole
Knowing R
COMP
, C
COMP
is calculated as follows:
(53)
(54)
The standard value of 10nF was selected for C
COMP
STEP4: Determine C
HF
to cancel ESR zero
Knowing R
COMP
and C
COMP
, C
HF
is calculated as follows:
(55)
(56)
Half of the maximum ESR is assumed as a typical ESR. The standard value of 150pF was selected for C
HF
.
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