Features: ·Low Output Noise in DSL Band
·Ceramic Input/Output Capacitors
·Step-Down or Step-Up/Step-Down Operation
·4.75V to 23V Input Supply Range
·0 to 18V Output Voltage Range (Up to 6A)
·>90% Efficiency
· Fixed-Frequency PWM Operation
·Adjustable 600kHz to 1.5MHz Switching Frequency
· External SYNC Input
· Clock Output for Master/Slave Synchronization
·Soft-Start and Soft-Stop
· RST Output with 140ms Minimum Delay
·Lossless Current Limit (No Sense Resistor)Application·xDSL Modems and Routers
·DSP, ASIC, and FPGA Power Supplies
·Set-Top Boxes
·Broadband RoutersPinout
SpecificationsV+ to GND ...........................................................-0.3V to +25V
PGND to GND ......................................................-0.3V to +0.3V
VL to GND ..................-0.3V to the lower of +6V and (V+ + 0.3V)
BST1, BST2 to GND ..............................................-0.3V to +30V
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 (VL + 0.3V)
CKO, REF, OSC, ILIM1, ILIM2,
COMP1, COMP2 to GND ................................-0.3V to (VL + 0.3V)
FB1, FB2, RST, SYNC, EN to GND..............................-0.3V to +6V
VL to GND Short Circuit..............................................Continuous
REF to GND Short Circuit ...........................................Continuous
Continuous Power Dissipation (TA = +70)
24-Pin QSOP (derate 9.4mW/ above +70)................762mW
Operating Temperature Range ...........................-40 to +85
Junction Temperature......................................................+150
Storage Temperature Range .............................-65 to +150
Lead Temperature (soldering, 10s) .................................+300
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 MAX8529 dual, synchronized, step-down controller generates two outputs from input supplies ranging from 4.75V to 23V. Each output is adjustable from sub-1V to 18V. Input voltage ripple and total RMS input ripple current are reduced by synchronized 180-degree out-ofphase operation.
The switching frequency is adjustable from 600kHz to 1.5MHz with an external resistor. Alternatively, the controller can be synchronized to an external clock generated to another MAX8529 or a system clock. One MAX8529 can be set to generate an in-phase, or 90- degree out-of-phase, clock signal for synchronization with additional controllers. This allows two controllers to operate either as an interleaved two- or four-phase system with each output shifted by 90 degrees. These MAX8529 also feature soft-start and soft-stop.
The MAX8529 eliminates the need for current-sense resistors by utilizing the low-side MOSFET's on-resistance as a current-sense element. This protects the DC-to-DC components from damage during output overload conditions or when output short circuit faults without requiring a current-sense resistor. Adjustable foldback current limit reduces power dissipation during short-circuit conditions. The MAX8529 includes a power-on reset output to signal the system when both outputs reach regulation.
The MAX8529 is available in a 24-pin QSOP package. An evaluation kit is available to speed designs.
MAX8529 Data Sheet
