MAX8650EEG+ Maxim Integrated Products, MAX8650EEG+ Datasheet - Page 23

• Manufacturer Part Number: MAX8650EEG+
• Description: IC CNTRLR STP DWN 24-QSOP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX8650EEG+

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 0.7 ~ 5.5 V
• Current - Output: 25A
• Frequency - Switching: 200kHz ~ 1.2MHz
• Voltage - Input: 4.5 ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-QSOP
• Power - Output: 762mW
• Output Voltage: 0.7 V to 5.5 V
• Output Current: 25 A
• Input Voltage: 4.5 V to 28 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

For the case where f
The power modulator gain at f
The error-amplifier gain at f
R
where g
C
C
Below is a numerical example to calculate R
values of the typical operating circuit of Figure 3:
A
L = 1.2µH
R
f
g
V
I
R
C
ESR = 3.5mΩ
G
S
OUT(MAX)
mc
OUT
C
VCS
DC
LOAD
C
F
OUT
MOD dc
= 500kHz
is calculated from:
is calculated as:
is calculated from:
= 1 / (A
= 2.16mΩ
= 12
= 3.3V
= 300µF
(
= V
R
mEA
)
C
=
=
= 15A
OUT
=
g
4.5V to 28V Input Current-Mode Step-Down
38 6
VCS
G
= 110µS.
mc
V
G
V
MOD fc
C
.
OUT
EA fc
FB
/ I
C
×
x R
×
C
OUT(MAX)
( )
=
0 22
R
R
0 22
F
______________________________________________________________________________________
( )
×
.
.
LOAD
DC
LOAD
R
=
(
g
R
=
LOAD
zMOD
2π
=
) = 1 / (12 x 0.00216) = 38.6S
mEA
×
+
LOAD
g
G
(
(
mEA
500 10
500 10
×
×
+
Controller with Adjustable Frequency
MOD dc
R
C
f
f
×
= 3.3 / 15 = 0.22Ω
S
S
is less than f
×
C
+
×
×
is:
f
G
×
×
×
S
1
C
(
×
f
L
L
MOD fc
S
R
× ×
f
is:
zMOD
3
3
C
×
)
f
L C
C
)
)
×
L
×
×
×
( )
)
f
f
⎛
⎜
⎝
⎛
⎜
⎝
f
pMOD
×
zMOD
zMOD
1 2 10
1 2 10
OUT
R
.
.
f
×
C
C
×
×
f
C
zMOD
:
−
−
6
6
C
⎞
⎟
⎠
⎞
⎟
⎠
and C
=
6 22
.
C
3.23kHz << f
Since f
Select the nearest standard value: R
Select the nearest standard value: C
Since the calculated value for C
the parasitic capacitance present at COMP), it is not
necessary:
R8 = R
C7 = C
C8 = C
G
C
C
=
=
f
zMOD
3 23
C
F
2
MOD fc
f
pMOD
.
π (
R
=
=
=
=
×
C
⎛
⎜
⎝
2
kHz
R
⎛
⎜
⎝
110 10
( )
=
(
π
300 10
=
zMOD
0 22
C
R
0 22 500 10
LOAD
C
F
.
2
×
g
.
LOAD
= 200kΩ
= Not installed
π
= 270pF
=
mEA
R
×
=
×
×
C
2π
(
+
G
C
1
×
(
×
C
> f
MOD dc
−
500 10
OUT
−
×
6
×
+
f
f
6
3 3
zMOD
1
S
≤ 100kHz, select f
V
⎞
⎟ ×
⎠
×
C
C
f
)
.
V
FB
S
× ×
×
OUT
:
×
(
OUT
×
0 7 0 201
×
⎛
⎜
⎜
⎜
⎜
⎝
L C
×
ESR
.
0 22
0 22
3
L
f
)
G
.
.
pMOD
=
)
) ( .
×
3
×
MOD fc
×
×
×
) ( .
2
OUT
=
f
.
×
+
R
×
π (
pMOD
1 2 10
⎛
⎜
⎝
(
(
C
2
×
R
R
500 10
500 10
f
( )
1 2 10
C
π (
LOAD
LOAD
<<
×
200 10
=
×
1
199
×
1
×
×
300 10
f
C
=
×
−
6 22
6
k
3
3
≤
F
−
×
+
Ω
×
.
C
) (
)
)
6
f
is very small (close to
f
f
×
×
×
3
1
5
S
S
S
)
= 100kHz:
1
⎞
⎟ ×
⎠
) (
⎛
⎜
⎝
⎛
⎜
⎝
×
1 2 10
1 2 10
C
−
300 10
C
×
×
×
.
.
6
100 10
(
L
L
= 200kΩ:
152 10
= 270pF:
)
200 10
×
×
×
3230
+
×
0 0035
×
ESR
.
×
−
−
×
6
6
−
⎞
⎟
⎠
⎞
⎟
⎠
6
3
3
⎞
⎟
⎠
)
+
3
)
=
=
)
0 0035
=
152
.
0 201
=
5 2
.
241
.
kHz
pF
23
⎞
⎟
⎟
⎟
⎟
⎠
p