Datasheet

MAX8570–MAX8575
High-Efficiency LCD Boost
with True Shutdown
6 _______________________________________________________________________________________
MAX8570–
MAX8575
EA
ILIM
THERMAL
SHUTDOWN
OUT
FB
(MAX8570/MAX8571/
MAX8574 ONLY)
GND
(MAX8572/MAX8573/
MAX8575 ONLY)
LX
SW
V
CC
1.226V
CONTROL
LOGIC
SHDN
Figure 1. Functional Diagram
MAX8570
MAX8571
MAX8574
SW
V
CC
LX
FB
GND
ON
OFF
V
CC
= 2.7V TO 5.5V
V
OUT
= V
BATT
TO 28V
R1
R2
C3
4.7
μ
F
L1
22
μ
H
C1
1
μ
F
SHDN
C2
1
μ
F
C4
10pF
V
BATT
= 0.8V TO 28V
D1
Figure 4. Using a Separate Input Supply for the Inductor
MAX8570
MAX8571
MAX8574
SW
V
CC
LX
FB
GND
ON
OFF
V
CC
= 2.7V TO 5.5V
+V
OUT
-V
OUT
R1
C3
4.7μF
L1
22μH
C1
1μF
SHDN
C2
1μF
C5
1μF
C4
10pF
C6
0.1μF
D1
D3
D2
R2
Figure 5. Negative Output Voltage for LCD Bias
MAX8570
MAX8571
MAX8574
SW
V
CC
LX
FB
GND
ON
OFF
V
CC
= 2.7V TO 5.5V
V
OUT
= V
CC
TO 28V
R1
R2
C3
4.7
μ
F
L1
22
μ
H
C1
1
μ
F
SHDN
C2
1
μ
F
C4
10pF
D1
Figure 2. Typical Application Circuit with Adjustable Output
Voltage
MAX8572
MAX8573
MAX8575
SW
V
CC
LX
OUT
GND
ON
OFF
V
CC
= 2.7V TO 5.5V
V
OUT
= 15V
C3
4.7
μ
F
L1
22
μ
H
C1
1
μ
F
SHDN
C2
1
μ
F
D1
Figure 3. Typical Application Circuit with 15V Preset Output
Voltage