SC2544 High Performance Wide Input Range Dual Synchronous Buck Controller POWER MANAGEMENT Description Features The SC2544 is a high performance dual PWM controller. Independent dual-outputs It is designed to convert a wide ranged input voltage down Wide input voltage range: 4.5V~28V to two independent output rails. The PWM operations of Adjustable output voltage down to 0.75V the two channels are 180 degree out of phase which Sequential and ratiometric start-up can greatly reduce the size and the cost of the input Power good output capacitors. Synchronous Buck PWM topology and volt- Synchronous Buck topology with voltage mode age mode control allow high efficiency operation, fast control transient responses, and flexible component selection Out of phase operation to reduce cost of input for easy designs. A 10V internal linear regulator pro- capacitor vides the bias for the controller, and this voltage is opti- 10V internal regulator for gate driver to deliver high mized for gate drivers to deliver high efficiency. The power efficiency sequencing is fully supported including independent start Programmable switching frequency: up, and power good output. In the shut down mode the 100kHz~300kHz controller only draws 100nA from the supply. The con- Full protection: UVLO, OVP and programmable troller also offers full protection features for the condi- tions of under voltage, over voltage, and the over current. OCP There is no need for a current sensing resistor because No need for current sense resistor the MOSFET on resistance is used for the sensing Low shutdown current (100nA typical) element. The switching frequency is adjustable from 100 24 lead TSSOP and MLPQ packages kHz to 300 kHz. Two packages TSSOP-24 and MLPQ-24 Fully WEEE and RoHS Compliant are offered. Applications Systems with 4.5V~28V input LCDTV and PDPTV Network and telecom systems Portable devices Typical Application Circuit SC2544 VO1 VIN+ 1 24 VIN AGND VCC 2 23 VCC ROSC 3 22 ENABLE EN PWRGD PWGRD 4 21 FB1 FB2 FB1 FB2 5 20 ERROUT1 ERROUT2 6 19 VIN+ SS1 SS2 VIN+ 7 18 ILIM1 ILIM2 8 17 BST1 BST2 9 16 VO2 VO1 DRVH1 DRVH2 10 15 PHASE1 PHASE2 11 14 DRVL1 DRVL2 FB1 VCC FB2 12 13 PGND PVCC Pinout shown as TSSOP-24. Revision: August 10, 2005 1 www.semtech.comSC2544 POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Parameter SmymbolMsaximu Unit BVST1,BST2 to PGND 3V8 bst VVIN to PGND 2V8 in ILIM1,ILIM2 and ENto PGND VVIN VCC and PVCC to PGND 1V4 PGND to AGND +V/-0.3 BST1 to PH1, BST2 to PH2,DRVH1 to PH1,DRVH2 to PH2 -V0.3 to 14 DRVL1,DRVL2 to PGND -V0.3 to VCC PHASE,DRVLto AGND pulse (100nS),peak voltage -V3 AllOtherPins to AGND -V0.3 to VCC o STtorage Temperature Range -60 to +150 C STG o JunctionTemperature T -40 to +150 C J Lead Temperature (Soldering)10 Sec forTSSOP-24 o LTead Temperature (IRReflow)forMLPQ-24 260 C LEAD ThermalResistance Junctionto Case o TSSOP-24 23 C/W JC MLP-24 2 ThermalResistance Junctionto Ambient o TSSOP-24 78 C/W JA MLP-24 25 Note: This device is ESD sensitive. Use of standard ESD handling precautions is required. Electrical Characteristics o Unless specified: T = 25 C, V =16V, Fs=200KHz . A IN Psarameter TnestCondition Mpi Txy Mta Uni Undervoltage Lockout SgtartThreshold V5cc risin 4V. UgVLOHysteresis V0cc fallin 2V0 m PowerSupply Operating Current(I -I)FSS1/SS2/EN=High,=0200kHz 60. 1Am IN PVCC S VVcc Regulated V0IN>12 1V VAcc Load RegulationLevelI2 load=0~20m % VVcc Line Regulation V2in=12~24 % PGVcc Operating Current2400KHz,1nF onHG,1nF onL 1Am Dwisable QuiescentCurrent E1N=lo 00. 1Au Main Switcheroutput LVine Regulation 55V<Vin<28 0%. LAoad Regulation 05A<load current<10 0%. O,utputVoltage Accuracy Withoutfeedback attenuation00.73505.75 0V.76 o o T =-40 C to +85 C A 2005 Semtech Corp. 2 www.semtech.com