Features: `Simple, Flexible Application Circuit
`2-Cell NiMH or Alkaline Operation (MAX1524)
`Low Quiescent Current (25A typ)
`Output Fault Protection and Soft-Start
`High Efficiency Over 1000:1 IOUT Range
`Pin-Selectable Maximum Duty Factor
`Micropower Shutdown Mode
`Small 6-Pin SOT23 Package
`No Current-Sense Resistor
Application·Low-Cost, High-Current,
·or High-Voltage Boost
·Conversion
·LCD Bias Supplies
·Industrial +24V and +28V
·Power Supplies
·Low-Cost, Multi-Output
·Flyback Converters
·SEPIC Converters
·Low-Cost Battery-
·Powered Applications
Pinout
SpecificationsVCC, FB, SHDN, SET to GND ...................................-0.3V to +6V
EXT to GND ..............................................-0.3V to (VCC + 0.3V)
Continuous Power Dissipation (TA = +70)
6-Pin SOT23 (derate 8.7mW/ above +70) ...... .........696mW
Operating Temperature Range ............................-40 to +85
Junction Temperature......................................................+150
Storage Temperature Range .............................-65 to +150
Lead Temperature (soldering, 10s) ................................+300DescriptionThe MAX1522/MAX1523/MAX1524 are simple, compact boost controllers designed for a wide range of DC-DC conversion topologies, including step-up, SEPIC, and flyback applications. They are for applications where extremely low cost and small size are top priorities. These devices are designed specifically to provide a simple application circuit and minimize the size and number of external components, making them ideal for PDAs, digital cameras, and other low-cost consumer electronics applications.
These devices use a unique fixed on-time, minimum offtime architecture, which provides excellent efficiency over a wide-range of input/output voltage combinations and load currents. The fixed on-time is pin selectable to either 0.5s (50% max duty cycle) or 3s (85% max duty cycle), permitting optimization of external component size and ease of design for a wide range of output voltages.
The MAX1522/MAX1523 operate from a +2.5V to +5.5V input voltage range and are capable of generating a wide range of outputs. The MAX1524 is intended for bootstrapped operation, permitting startup with lower input voltage. All devices have internal soft-start and short-circuit protection to prevent excessive switching current during startup and under output fault conditions. The MAX1522/MAX1524 have a latched fault mode, which shuts down the controller when a shortcircuit event occurs, whereas the MAX1523 reenters soft-start mode during output fault conditions. The MAX1522/MAX1523/MAX1524are available in a spacesaving 6-pin SOT23 package.
MAX1522 Data Sheet
