MAX5072ETJ+ Maxim Integrated Products, MAX5072ETJ+ Datasheet - Page 23

IC CONV BUCK/BOOST 32-TQFN

MAX5072ETJ+

Manufacturer Part Number
MAX5072ETJ+
Description
IC CONV BUCK/BOOST 32-TQFN
Manufacturer
Maxim Integrated Products
Type
Step-Down (Buck), Step-Up (Boost)r
Datasheet

Specifications of MAX5072ETJ+

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
2
Voltage - Output
0.8 ~ 28 V
Current - Output
1A, 2A
Frequency - Switching
200kHz ~ 2.2MHz
Voltage - Input
4.5 ~ 23 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
32-TQFN Exposed Pad
Power - Output
2.76W
Output Voltage
5.2 V
Output Current
2 A
Input Voltage
5.5 V to 23 V
Supply Current
2.2 mA
Switching Frequency
1250 KHz
Mounting Style
SMD/SMT
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
The transconductance error-amplifier gain is:
The total loop gain at f
or
Place a zero at or below the LC double pole:
Place a high-frequency pole at f
Procedure 2 (See Figure 8):
If the output capacitor used is a low-ESR ceramic type,
the ESR frequency is usually far away from the targeted
unity crossover frequency (f
pensation is recommended. Type III compensation pro-
vides two-pole zero pairs. The locations of the zero and
poles should be such that the phase margin peaks at f
The
phase margin at f
the two zeros at or below the double pole to avoid the
conditional stability issue.
Select a crossover frequency:
Calculate the LC double-pole frequency, f
Place a zero
where:
and R
f
f
F
Z
C
≥ 10kΩ.
=
R
f
F
f
Z
f
C
P
=
Converter with POR and Power-Fail Output
=
f
= 5
LC
V
C
2
OSC
π
F
=
C
______________________________________________________________________________________
C
×
=
is a good number to get about 60°
F
. However, it is important to place
G
G
R
(
2
ESR
0 8
=
E A
1
M
C
f
F
π
.
C
×
/
should be equal to 1
×
×
×
×
=
C
G
L
0 75
+
C
×
f
V
.
OUT
SW
F
g
E A
20
2
IN
). In this case, Type III com-
R
m
/
π
1
1
F
at
2.2MHz, Dual-Output Buck or Boost
1
×
×
×
×
P
=
×
×
g
f
R
f
= 0.5 x f
LC
0 75
C
m
1
f
C
F
LC
.
×
OUT
×
×
L
ESR
OUT
R
×
F
SW
LC
f
LC
)
V
:
.
OUT
C
.
Calculate C
Place a pole
Place a second zero, f
is lower.
Place a second pole
switching frequency.
The boost converter compensation gets complicated
due to the presence of a right-half-plane zero
F
phase while adding positive (+1) slope to the gain curve.
It is important to drop the gain significantly below unity
before the RHP frequency. Use the following procedure
to calculate the compensation components.
Calculate the LC double-pole frequency, f
right half plane zero frequency.
where:
Target the unity-gain crossover frequency for:
ZERO,RHP
C
I
=
. The right-half-plane zero causes a drop in-
C
I
CF
for a target unity crossover frequency, f
f
f
(f
LC
ZERO RHP
P
R
R
1
=
×
1
D
I
R
=
=
f
(
=
C
=
2
(
,
= −
MIN
2
π
2
2
×
π
1
π
Boost Converter Compensation
π
(
×
Z2
f
×
)
L
P
×
×
0 5
×
2
OUT
=
, at 0.2f
V
=
.
R
V
1
f
V
OUT
f
1
L
ZERO ESR
I
I
=
IN
Z
1
IN
OUT MAX
(
OUT OUT
×
1
2
×
2
V
2
×
×
f
D
C
×
π
SW
OUT
π
1
(
D
C
R
I
C
,
C
C
C
×
×
)
OUT
F
at f
I
F
2
R
or at f
×
L
F
R
1
OUT
)
R
ZERO,ESR
R
(
×
×
F
MIN
×
I
C
C
LC
×
V
I
OSC
CF
)
C
, whichever
F
LC
)
)
.
, and the
at 1/2 the
1
C
23
:

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