SEMTECH SC451

SC451 Portable IMVP-IV™ and IMVP-IV+™ Single Phase Power Supply Controller POWER MANAGEMENT Description Features The SC451 PowerStep IV™ IC is a single chip high-perfor- ! IMVP-IV™ and IMVP-IV+™ compliant single chip mance Hysteretic PWM controller. With its integrated solution SmartDriver™, it powers advanced IMVP-IV™ and IMVP4+™ ! On-chip CLK_ENABLE# and IMVP4_PWRGD outputs processors. The SC451 features extended Intel Mobile Volt- ! Backward compatible with SC1479 age Positioning (IMVP™) to increase battery life by reduc- ! High-speed hysteretic controller ing the voltage at the processor when it is heavily loaded. ! Single-phase operation It directly supports Intel’s SpeedStep® processors for even ! Selectable analog or VID controlled DeeperSleep longer battery life. The SC451 fully supports the Intel® setting Geyserville-III core voltage specification. It provides direct ! 6 bit VID programmable output “deeper sleep” mode and boot voltage support. Automatic ! Integrated drivers with soft high side turn-on “power-save” is present to prevent negative current flow in ! Programmable softstart the low-side FET during light loading conditions, saving even ! Programmable boot voltage more power. The high side driver initially turns on with a weak drive to reduce ringing, EMI, and capacitive turn-on ! Programmable DeeperSleep voltage of the low side. ! Under-voltage lock out on VccA ! Over-voltage protection on CORE A 6-bit DAC, accurate to 0.85%, sets the output voltage ! Current limit protection on CORE reference, and implements the 0.700V to 1.708V range ! Thermal protection required by the processor. The hysteretic converter uses a ! Powergood flag with blanking during VID or comparator without an error amplifier, and therefore pro- DeeperSleep mode changes vides the fastest possible transient response, while avoid- ! Automatic powersave at light load ing the stability issues inherent to classical PWM control- ! TSSOP-28 and TSSOP-38 package options lers. The DAC is externally slew rate limited to minimize transient currents and audible noise. Applications The SC451 operates from 5VDC and also features soft- ! Low power Notebook and Laptop computers start, an open-drain PWRGD signal with power-good blank- ! Embedded Applications ing, and an enable input. Programmable current limiting shuts down the SC451 after 32 current limit pulses. It PowerStep IV™ is a trademark of Semtech comes in both a TSSOP-28 and TSSOP-38 package. The Corporation. TSSOP-38 provides a pin-to-pin upgrade to a dual-phase Other trademarks or registered trademarks may be solution using Semtech’s dual-phase controller, SC450. claimed as the property of others. Conceptual Application Circuit V 5 VIN V CCA VCORE Smart 0.700V-1.708V Driver PWM Controller SC451 Single Phase IM VP-IV/IM VP-IV+ Power Supply VID Logic VID (5:0) and D AC June 6, 2005 1 www.semtech.com