MAX8513EEI+ Maxim Integrated Products, MAX8513EEI+ Datasheet - Page 26

• Manufacturer Part Number: MAX8513EEI+
• Description: IC SUPPLY TRPL W/MON 28QSOP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX8513EEI+

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 3
• Voltage - Output: 1.25 ~ 5.5 V
• Current - Output: 40mA
• Frequency - Switching: 300kHz ~ 1.4MHz
• Voltage - Input: 4.5 ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-QSOP
• Power - Output: 860mW
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Wide-Input, High-Frequency, Triple-Output Supplies
with Voltage Monitor and Power-On Reset
This gain between f
R3/R1, where R1 is selected in the OUT1 Voltage
Setting section. Therefore:
And similar to Case 1, C5 can be calculated as:
Set the error-amplifier third pole, f
1/2 the switching frequency. The gain of the error
amplifier at f
of R3/R
where R
Therefore:
Similar to Case 1, R4, C11, and C12 can be calculated as:
Below is a numerical example to calculate the error-
amplifier compensation values for Case 2:
V
V
V
V
L1A = 6.2µH
C4 = 560µF/ 10V OS-Con capacitor, with ESR = 0.015Ω
f
26
S
IN
RAMP
OUT1
FB1
= 300kHz
= 12V (nomimal input voltage)
______________________________________________________________________________________
= 1.25V
= 3.3V
I
= 1V
I
and is also equal to:
is:
C
12
C
R
C
(between f
I
R
C
G
11
=
3
=
5
EA fc
2
=
=
( )
R
Z1
=
R
R
π
3
4
I
f
2
and f
π
ZESR
×
=
×
=
π
=
×
R
×
C
P2
G
R
1
R
R
R
G
5
1
R
MOD fc
1
R
1
Z2
1
×
×
MOD fc
and f
3
+
4
×
×
C
×
-
1
2
G
is also set by the ratio of
f
×
1
PMOD
5
×
R
R
( )
R
R
R
MOD fc
4
( )
3
I
4
I
f
f
PMOD
P3
ZESR
P3
×
×
) is set by the ratio
( )
, at approximately
G
f
P
D
3
-
1
Pick R2 = 8.06kΩ. Then:
Pick f
Use 20kΩ.
Use 12nF.
Use 2.2kΩ.
Use 3.9nF.
Pick f
C
C
G
G
R
11
R
R
3
MOD DC
EA fZ fZ
5
C
I
4
P
=
3 = f
=
(
=
f
f
= 50kHz, which is less than f
=
ZESR
PMOD
=
(
2
1
R
π
−
R
π
1
R
S
R R
R
3
G
×
×
)
1
×
1-
1
2
R
R
/ 2 = 150kHz.
MOD DC
×
×
)
=
=
=
=
=
3
4
=
G
R
=
1
=
×
×
I
G
2
I
EA fZ fZ
12
2
2
2
2
18 95
f
f
f
8 06
(
=
MOD fc
ZESR
ZESR MOD fc
PMOD
π
π
π
π
.
(
R
.
13 3
×
13 3
×
ESR
L A
)
6 2
18 95
1
0 015
f
.
1
k
PMOD
-
.
.
( )
kHz
.
2 7
G
1
1
Ω
=
=
k
.
.
k
µ
2
=
Ω
×
Ω
2
×
H
×
)
V
kHz
1
=
π
1
×
π
C
1 25
RAMP
=
×
2 7
kHz
C
Ω
-
V
×
3 3
20
×
1 846
.
.
13 3
1 846
0 0923
×
4
IN
4
.
( )
.
560
×
2 2
.
.
20
kHz
k
.
V
.
560
V
Ω
×
k
k
k
µ
-
Ω
Ω
×
k
Ω
k
2
1
=
F
50
2
Ω
1
µ
0 0923 1 846
Ω
×
×
=
×
S
F
.
=
12
18 95
=
kHz
2 7
1 543 20 48
1 543
=
/ 5.
13 3
2 7
=
.
.
.
2 14
.
.
18 95
kHz
.
.
kHz
=
kHz
.
k
=
Ω
=
k
0 0923
Ω
.
=
.
kHz
11 8
=
.
3 82
.
.
k
k
nF
Ω
Ω
nF