PM6685 Datasheet | STMicroelectronics

.. DUAL STEP-DOWN CONTROLLER WITH AUXILARY VOLTAGES FOR NOTEBOOK SYSTEM POWER Preliminary Data Features - CONSTANT ON TIME TOPOLOGY ALLOWS VERY FAST LOAD TRANSIENTS 6V TO 28V INPUT VOLTAGE RANGE FIXED 5V-3.3V OUTPUT VOLTAGES 5V AND 3.3V ALWAYS VOLTAGES AVAILABLE DELIVER 100m A PEAK CURRENT 1.23V ± 1% REFERENCE VOLTAGE AVAILABLE NO RSENSE CURRENT SENSING USING LOW SIDE MOSFETs’ RDS(on) ACCURATE CURRENT SENSE WITH RSENSE NEGATIVE CURRENT LIMIT SOFT START INTERNALLY FIXED AT 2ms SOFT OFF FOR OUTPUT DISCHARGE LATCHED OVP AND UVP SELECTABLE PULSE SKIPPING AT LIGHT LOADS SELECTABLE MINIMUM FREQUECY (25k Hz) IN PULSE SKIP MODE 4 m W MAXIMUM QUIESCENT POWER INDIPENDENT POWER GOOD SIGNALs OUTPUT VOLTAGE RIPPLE PENSATION VFQFPN-32 5X5 - - - - Description PM6685 is a dual step-down controller specifically designed to provide extremely high efficiency conversion, with lossless current sensing technique. The constant on-time architecture assures fast load transient response and the embedded voltage feed-forward provides nearly constant switching frequency operation. An embedded integrator control loop pensates the DC voltage error due to the output ripple. Pulse skipping technique increases efficiency at very light load. Moreover a minimum switching frequency of 25k Hz is selectable to avoid audio noise issues. The PM6685 provides a selectable switching frequency, allowing either 200k Hz/ 300k Hz, 300k Hz/400Khz or 400k Hz/500k Hz operation of the 5V/3.3V switching sections... - - - - - - - - - - - Applications - - - - NOTEBOOK PUTERS TABLET PC OR SLATES MOBILE SYSTEM POWER SUPPLY 3-4 CELLS Li+ BATTERY POWERED DEVICES Order codes Part number PM6685 September 2005 This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice. Marking PM6685 Package VFQFPN-32 5X5 Packing TAPE & REEL Rev 1 1/16 .st. 16 Contents 1 2 3 4 5 6 7 Typical application...