LM3000

LM3000 Dual Synchronous Emulated Current-Mode Controller www.DataSheet4U.com July 2, 2009 LM3000 Dual Synchronous Emulated Current-Mode Controller General 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 kHz 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 redu...