1 www.semtech.com sc450 portable imvp-iv? and imvp4+? dual phase power supply controller power management revision: may 21, 2004 description features applications typical application circuit ? imvp-iv? and imvp4+ ? compliant single chip solution ? on chip clk_enable# and imvp4_pwrgd outputs ? backward compatible with sc1476 ? high speed hysteretic controller ? 6 bit vid programmable output ? integrated drivers with soft high side turn-on ? programmable softstart ? programmable boot voltage ? programmable deepersleep voltage ? dynamic phase current matching ? under-voltage lockout on vcca ? over-voltage protection on core ? current limit protection on core ? thermal protection ? powergood flag with blanking during vid or deepersleep mode changes ? automatic powersave at light load ? slew rate limited dac ? tssop-38 package the sc450 powerstep iv? ic is a single chip high-per- formance hysteretic pwm controller. with its integrated smartdriver?, it powers advanced imvp-iv? and imvp4+? processors. the sc450 features extended intel mobile voltage positioning (imvp?) to increase battery life by reducing the voltage at the processor when it is heavily loaded. it directly supports intel?s speedstep? processors for even longer battery life. the sc450 fully supports the intel? geyserville-iii core voltage specifi- cation. it provides direct ?deeper sleep? mode and boot voltage support. automatic ?power-save? is present to prevent negative current flow in the low-side fet during light loading conditions, saving even more power. the high side driver initially turns on with a weak drive to reduce ringing, emi, and capacitive turn-on of the low side. a 6-bit dac, accurate to 0.85%, sets the output voltage reference, and implements the 0.700v to 1.708v range required by the processor. the hysteretic converter uses a comparator without an error amplifier, and therefore provides the fastest possible transient response, while avoiding the stability issues inherent to classical pwm controllers. the dac is externally slew rate limited to mini- mize transient currents and audible noise. the sc450 operates from 3.3v and 5v. it also features soft-start, an open-drain pwrgd signal with power-good blanking, and an enable input. programmable current limiting shuts down the sc450 after 32 current limit pulses. in addition, it comes in a space-saving tssop- 38 package. sc1474 d ual p hase extended i mvp contro ller vi d [4 :0 ] lo +vcore +v _i n +v _5 0.600v -1.75v u p to 4 0 a ext ended i mvp logi c pw m cont ro l l er pow er c ontrol si gnal s sm art dri ve r vi d mul t i pl exer lo co sm art dri ve r rcs rcs +v _3 +v _v i d vi d r egul at or cont ro l l er sc1474 d ual p hase extended i mvp contro ller vi d [4 :0 ] lo +vcore +v _i n +v _5 0.600v -1.75v u p to 4 0 a ext ended i mvp logi c pw m cont ro l l er pow er c ontrol si gnal s sm art dri ve r vi d mul t i pl exer lo co sm art dri ve r rcs rcs +v _3 +v _v i d vi d r egul at or cont ro l l er vid[5:0] vid[5:0] vid[5:0] vid[5:0] vid[5:0] ? notebook and laptop computers ? embedded applications powerstep iv? and smartdriver? are trademarks of semtech corporation. other trademarks or registered trademarks may be claimed as the property of others. 4 .com datasheet u
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