LM3000 Datasheet | National Semiconductor

Description The LM3000 is a dual output synchronous buck controller which is designed to convert input voltages ranging from 3.3V to 18.5V down to output voltages as low as 0.6V. The two outputs switch at a constant programmable frequency of 200 k Hz to 1.5 MHz, with the second output 180 degrees out of phase from the first to minimize the input filter requirements. The switching frequency can also be phase locked to an external frequency. A CLKOUT provides an external clock 90 degrees out of phase with the main clock so that a second chip can be run out of phase with the main chip. The emulated current-mode control utilizes bottom side FET sensing to provide fast transient response and current limit without the need for external current sense resistors or RC networks. Separate Enable, Soft-Start and Track pins allow each output to be controlled independently to provide maximum flexibility in designing system power sequencing. The LM3000 has a full range of protection features which include input under-voltage lock-out (UVLO), power good (PGOOD) signals for each output, over-voltage crowbar and hiccup mode during short circuit events. Features - - - - - - - - - - VIN range from 3.3V to 18.5V Output voltage from 0.6V to 80% of VIN Remote differential output voltage sensing 1% accuracy at FB pin Interleaved operation reduces input capacitors Frequency sync/adjust from 200 k Hz to 1.5 MHz Startup with pre-bias load Independent power good, enable, soft-start and track Programmable current limit without external sense resistor Hiccup mode short circuit protection Applications - - - - - - DC Power Distribution Systems Graphic Cards - GPU and Memory ICs FPGA, CPLD, and ASICs Embedded Processor 1.8V and 2.5V I/O Supplies Networking Equipment (Routers, Hubs) Simplified Application 300905a1 © 2009 National Semiconductor Corporation .national. .. Connection Diagram Top View 32-Lead LLP Ordering Information Order Number Package Marking...