Features: · Fixed 200kHz, 300kHz, or 500kHz Switching Frequency
· No Current-Sense Resistor Required
· 40/60 Optimal Interleaving
· Reduced Input-Capacitor Requirement
· 3.3V and 5V fixed or 1.0V to 5.5V Adjustable Outputs (Dual Mode™)
· 4V to 26V Input Range
· Independently Selectable PWM, Skip, and Low-Noise Mode Operation
· Soft-Start and Soft-Stop
· 2V Precision Reference with 0.75% Accuracy
· Independent Power-Good OutputsApplication·2 to 4 Li+ Cell Battery-Powered Devices
·Notebook and Subnotebook Computers
·PDAs and Mobile Communicators
·Main or I/O Power SuppliesPinout
SpecificationsVDD, VCC, CSL1, CSH1, CSL2, CSH2 to AGND ......-0.3V to +6V
ON1, ON2, SKIP1, SKIP2, PGOOD1,
PGOOD2 to AGND...............................................-0.3V to +6V
FB1, FB2, ILIM1, ILIM2, FSEL to AGND ..................-0.3V to +6V
REF to AGND.............................................-0.3V to (VCC + 0.3V)
BST1, BST2 to AGND............................................-0.3V to +36V
LX1 to BST1...........................................................-6V to +0.3V
LX2 to BST2...........................................................-6V to +0.3V
DH1 to LX1 ...........................................-0.3V to (VBST1 + 0.3V)
DH2 to LX2 ...........................................-0.3V to (VBST2 + 0.3V)
DL1, DL2 to PGND ....................................-0.3V to (VDD + 0.3V)
AGND to PGND....................................................-0.3V to +0.3V
REF Short Circuit to AGND........................................Continuous
REF Current ...................................................................+10mA
Continuous Power Dissipation (TA = +70°C)
24-Pin Thin QFN 4mm x 4mm (derate 20.8mW/°C
above +70°C).......................................................1666.7mW
28-Pin Thin QFN 5mm x 5mm (derate 21.3mW/°C
above +70°C)........................................................1702.1mW
Operating Temperature Range .......................-40°C to +85°C
Junction Temperature....................................................+150°C
Storage Temperature Range .........................-65°C to +150°C
Lead Temperature (soldering, 10s) ...............................+300°C
Note 1: For the 24-pin TQFN version, AGND and PGND refer to a single pin designated GND.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DescriptionThe MAX8716/MAX8717/MAX8757 are dual, stepdown,interleaved, fixed-frequency, switch-mode power-supply (SMPS) controllers with synchronous rectification.They are intended for main (5V/3.3V) and I/O power generation in battery-powered systems.
Fixed-frequency operation of MAX8757 with optimal interleaving minimizes input ripple current from the lowest input voltages up to the 26V maximum input. Optimal 40/60 interleaving allows the input voltage to go down to 8.3V before duty-cycle overlap occurs, compared to 180°out-of-phase regulators where the duty-cycle overlap occurs when the input drops below 10V.
Accurate output current limit of MAX8757 is achieved using a sense resistor. Alternatively, power dissipation can be reduced using lossless inductor current sensing.Independent ON/OFF controls and power-good signals allow flexible power sequencing. Soft-start of MAX8757 reduces inrush current, while soft-stop gradually ramps the output voltage down preventing negative voltage dips.
A low-noise mode of MAX8757 maintains high light-load efficiency while keeping the switching frequency out of the audible range.
The MAX8716 is available in a 24-pin thin QFN package,and the MAX8717/MAX8757 are available in a 28-pin thin QFN package.
MAX8757 Data Sheet
