SC2443_08

SC2443 POWER MANAGEMENT Features u Wide input voltage range: 4.7V to 16V u 0.5V feedback voltage for low-voltage outputs u Programmable frequency up to 1 MHz per phase u 2-Phase synchronous continuous conduction mode for high efficiency step-down converters u Out-of-phase operation for low input current ripples u Output source and sink currents u Fixed frequency peak current-mode control u 75mV/-110mV maximum current sense voltage u Inductor DCR current-sensing for low-cost applications u Dual outputs or 2-phase single output operation u Excellent current sharing between individual phases u Individual soft-start, overload shutdown and enable u External reference input for DDR applications u External synchronization u Industrial temperature range u 4mm X 4mm X1mm 24-lead MLPQ package Dual-Phase Single or Two Output Synchronous Step-Down Controller Description The SC2443 is a high-frequency dual synchronous step-down switching power supply controller. It provides out-of-phase high-current output gate drives to all N-channel MOSFET power stages. The SC2443 operates in synchronous continuous-conduction mode. Both phases are capable of maintaining regulation with sourcing or sinking load currents, making the SC2443 suitable for generating both VDDQ and the tracking VTT for DDR applications. The SC2443 employs fixed frequency peak current-mode control for the ease of frequency compensation and fast transient response. The dual-phase step-down controllers of the SC2443 can be used to produce two individually controlled and regulated outputs or a single output with shared current in each phase. The Step-down controllers operate from an input of at least 4.7V and are capable of regulating outputs as low as 0.5V Individual soft-start and overload shutdown timer is included in each step-down controller. The SC2443 implements hiccup overload protection. In single output current share configuration, the master timer controls the soft-start and overload shutdown functions of both controllers. Applications u Telecommunication power supplies u DDR memory power supplies u Graphic power supplies u Servers and base stations Typical Application Circuit VOUT1 VP1 VIN VIN VOUT1 VP1 VIN VIN VP1 24 23 22 21 20 19 VOUT1 24 23 22 21 20 19 VP1 IN1- VOUT1 IN1- U1 1 2 3 4 5 6 U1 1 2 CS1+ SS1/EN1 BST1 CS1- SS1/EN1 ROSC GDH1 ROSC GDH1 CS1+ BST1 CS1- IN1- IN1- GDL1 PVCC PGND 18 17 16 15 14 13 VIN IN1- IN1- GDL1 PVCC PGND 18 17 16 15 14 13 VIN COMP1 SYNC AGND REF SS2/EN2 COMP2 AVCC COMP1 SYNC AGND REF AVCC 12 3 4 VOUT2 IN2- SC2443 GDL2 GDH2 BST2 SC2443 GDL2 GDH2 SS2/EN2 5 6 CS2- IN2- 10 11 12 7 8 9 10 CS2+ CS2- REFIN COMP2 CS2+ REFIN BST2 IN2- VIN 11 7 8 9 VIN IN2- Dual Independent Outputs Single Output With Current Sharing Aug. 2008 1 SC2443 Pin Configuration Top View SS1/EN1 ROSC 24 Ordering Information Device SC2443MLTRT (1,2) SC2443EVB GDH1 BST1 Package 24-lead 4mm X 4mm X mm MLPQ Evaluation Board CS1+ CS1- 19 IN1COMP1 SYNC AGND REF REFIN 1 18 GDL1 PVCC PGND GDL2 GDH2 Notes: () Available in tape and reel only. A reel contains 3,000 devices. (2) Available in lead-free package only. Device is WEEE and RoHS compliant. 6 13 BST2 7 12 CS2- (24-lead 4mm X 4mm X mm MLPQ) θJA = 29°C/W Marking Information Marking for the 4 X 4mm MLPQ-24 package: COMP2 SS2/EN2 AVCC IN2- CS2+ 2 SC2443 Absolute Maximum Ratings AVCC, PVCC Voltage …………………………… VBST1, VBST2 Voltage ……………………………… -0.3 to 20V -0.3 to 32V Recommended Operating Conditions Input Voltage Range ………………………… 4.75V to 16V ……………………………… - 0.3 to 40V (for