MAX1763 Ver la hoja de datos (PDF) - Maxim Integrated
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MAX1763 Datasheet PDF : 18 Pages
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1.5A, Low-Noise, 1MHz, Step-Up
DC-DC Converter
OUT
ONA
ONB
REF
GND
CLK/SEL
FB
ISET
AIN
IC POWER
2.15V
UNDERVOLTAGE LOCKOUT
1.25V
ON
RDY
REFERENCE
REF
DUAL
MODE/
FB
CONTROLLER
POUT
STARTUP
EN OSCILLATOR Q
D
Q
P
LX
EN
1MHz
OSCILLATOR
EN
OSC
Q
N
MODE
PGND
FB ISET
0.938V
GAIN
BLOCK
MAX1763
AO
N
Figure 1. Functional Diagram
Table 1. Typical Available Output Current
NUMBER
OF CELLS
INPUT
VOLTAGE
(V)
OUTPUT
VOLTAGE
(V)
OUTPUT
CURRENT
(mA)
1 NiCd/NiMH
1.2
3.3
675
2.4
2 NiCd/NiMH
2.4
3.3
1500
5.0
950
1 Li+
2.7 (min)
3.3
1300
1 Li+
2.7 (min)
5.0
1100
3 NiCd/NiMH
3.6
5.0
1600
In its normal mode of operation (CLK/SEL = low), the
MAX1763 offers fixed-frequency PWM operation through
most of its load range. At light loads (less than 25% of full
load), the device automatically optimizes efficiency by
switching only as needed to supply the load. Shutdown
reduces quiescent current to just 1µA. Figure 2 shows
the standard application circuit for the MAX1763. (An
external Schottky diode is needed for output voltages
greater than 4V, or to assist low-voltage startup.)
Additional features include synchronous rectification for
high efficiency and increased battery life, and a gain
block that can be used to build a linear regulator using
an external P-channel MOSFET pass device. This gain
C3
0.22μF
VIN
0.7V TO 5.5V
L1
1.5μH
CLK/SEL
LX
ONA
POUT
MAX1763
ONB
OUT
AIN
ISET
REF
PGND
AO
FB
GND
C1
47μF
MBR0520L
D1
R5
4.7Ω
C2
1.0μF
OUT
3.3V
C4
2 x 100μF
NOTE: HEAVY LINES INDICATE HIGH-CURRENT PATHS.
Figure 2. PFM/PWM Automode Connection
block can also function as a voltage-monitoring com-
parator. The MAX1763 is available in a 16-pin QSOP
package or a 1.5W 16-pin TSSOP-EP package for high-
temperature or high-dissipation applications.
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