Part # LM2648 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: LM2648 Two-Phase, Synchronous Step-Down 3-Channel Switching Regulator Controller

Part Details:

LM2648 December 2004 T LM2648 wo-Phase, Two-Phase, Synchronous Step-Down 3-ChannelSwitching Regulator ControllerGeneral Description Features Synchronous The LM2648 consists of two current mode and two voltage n Four synchronous buck regulators mode synchronous buck regulator controllers providing 3 n Channel 3: Two-phase, current mode controller outputs at a switching frequency of 300kHz. n 4.5V to 18V input range Each pair of switching regulator controllers operate 180° out n Built in sequential startup of phase. This feature reduces the input ripple RMS current, n Channels 1 and 2: Independent, 180° out of phase thereby significantly reducing the required input capacitance. voltage mode controllers The two current mode regulator outputs operate as a dual- n Single soft start for channels 1 and 2 phase, single output regulator for high current applications. n Adjustable cycle-by-cycle current limit for each channel Current-mode feedback control on Channel 3 assures supe- n Adjustable reference current rior line and load regulation and wide loop bandwidth as- Step-Down n Adjustable input under-voltage lockout sures excellent response to fast load transients. Channels 1 n Output over-voltage latch protection and 2 employ voltage-mode feedback control. n Output under-voltage protection with delay The LM2648 features analog soft-start circuitry that is inde- n Two comparator inputs for user defined protection - one pendent of the output load and output capacitance. This with delay makes the soft-start behavior more predictable than tradi-tional soft-start circuits. Sequential startup is built in and n Thermal shutdown requires a single capacitor to set the timing. n Self-discharge of output capacitors when the regulator is off The LM2648 has over-voltage protection and under-voltage 3-Channel protection for all outputs. Two additional comparator inputs n TSSOP package (analog and logic level) are provided to shut down the IC forany user defined protection. The FAULT_DELAY pin allows Applications delayed shut off time for the IC during an under-voltage or n Embedded Computer Systems PROT-IN2 fault. The LM2648 also features an adjustable n Interactive Games UVLO feature. n Set-top Boxes/Home Gateways Switching

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LM2648.pdf Datasheet