MAX770EPA View Datasheet(PDF) - Maxim Integrated
Part Name
Description
Manufacturer
MAX770EPA
Maxim Integrated
MAX770EPA Datasheet PDF : 20 Pages
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5V/12V/15V or Adjustable, High-Efficiency,
Low IQ, Step-Up DC-DC Controllers
VIN = 3V
C3
0.1µF
C2
0.1µF
2
V+
5 REF
4
MAX770
SHDN
L1
22µH
C1
100µF
D1
1N5817
3 FB
6 AGND
GND
7
1
EXT
8
CS
N
MTP3055EL
RSENSE
75mΩ
VOUT = 5V
@ 1A
C4
300µF
Figure 2a. 5V Preset Output, Bootstrapped
VIN = 5V
C3
0.1µF
C2
0.1µF
2
V+
5 REF
4
MAX771
SHDN
L1
22µH
C1
68µF
D1
1N5817
3 FB
6 AGND
GND
7
1
EXT
8
CS
N
Si9410DY
RSENSE
100mΩ
VOUT = 12V
@ 0.5A
C4
200µF
Figure 2b. 12V Preset Output, Bootstrapped
VIN = 5V
C1
C2
68µF
0.1µF
2
V+
5 REF
C3
0.1µF
4
SHDN
MAX770
MAX771
MAX772
6 AGND
GND
7
( ) R2 = (R1) VOUT -1
VREF
VREF = 1.5V
L1
22µH D1
1N5817
EXT 1
N
8
CS
FB 3
RSENSE
100mΩ
R1
18k
Figure 2c. 12V Output, Non-Bootstrapped
VOUT = 12V
@ 0.5A
C4
200µF
R2
127k
VIN = 4V
C3
0.1µF
C2
0.1µF
2
V+
5 REF
4
SHDN
MAX770
MAX771
MAX772
6 AGND
GND
7
( ) R2 = (R1) VOUT -1
VREF
VREF = 1.5V
L1
20µH
C1
47µF
D1
1N5817
VOUT = 9V
1
EXT
8
CS
3
FB
N
Si9410DY
C4
100µF
RSENSE
R2
140k
R1
28k
Figure 2d. 9V Output, Bootstrapped
frequencies (up to 300kHz), allowing the use of tiny
external components.
As with traditional PFM converters, the power transistor
is not turned on until the voltage comparator senses
that the output is out of regulation. However, unlike tra-
ditional PFM converters, the MAX770–MAX773 switch
using the combination of a peak current limit and a pair
of one-shots that set the maximum on-time (16µs) and
minimum off-time (2.3µs); there is no oscillator. Once
off, the minimum off-time one-shot holds the switch
off for 2.3µs. After this minimum time, the switch either
1) stays off if the output is in regulation, or 2) turns on
again if the output is out of regulation.
The control circuitry allows the ICs to operate in contin-
uous-conduction mode (CCM) while maintaining high
efficiency with heavy loads. When the power switch is
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