SC2545 High Performance Wide Input Range Dual Synchronous Buck Controller POWER MANAGEMENT Description Features Independent dual-outputs The SC2545 is a high performance dual PWM controller. It is designed to convert a wide ranged input voltage down Peel off start up trackingIndependent dual-outputs to two independent output rails. The SC2545 support Wide input voltage range: 4.5V~28V peel off tracking for the two outputs at start up which Adjustable output voltage down to 0.75V means the two outputs ramp up together till the one Flexible power sequencing with enable and power with lower output level reaching the regulation. The PWM good output operations of the two channels are 180 degree out of Synchronous Buck topology with voltage mode phase which can greatly reduce the size and the cost of control the input capacitors. Synchronous Buck PWM topology Out of phase operation to reduce cost of input and voltage mode control allow high efficiency operation, capacitor fast transient responses, and flexible component selec- 10V internal regulator for gate driver to deliver high tion for easy designs. A 10V internal linear regulator pro- efficiency vides the bias for the controller, and this voltage is opti- Programmable switching frequency: mized for gate drivers to deliver high efficiency. The power 100kHz~300kHz sequencing is fully supported including independent start up, and power good output. In the shut down mode the Full protection: UVLO, OVP and programmable controller only draws 100nA from the supply. The con- OCP troller also offers full protection features for the condi- No need for current sense resistor tions of under voltage, over voltage, and the over current. Low shutdown current (100nA typical) There is no need for a current sensing resistor because 24 lead TSSOP and MLPQ packages the MOSFET on resistance is used for the sensing Fully WEEE and RoHS Compliant element. The switching frequency is adjustable from 100 Applications kHz to 300 kHz. Two packages TSSOP-24 and MLPQ-24 are offered. Systems with 4.5V~28V input LCDTV and PDPTV Network and telecom systems Typical Application Circuit SC2545 VO1 VIN+ 1 24 VIN AGND VCC 2 23 VCC ROSC 3 22 ENABLE PWGRD EN PWRGD 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.comSC2545 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 ESD Rating (HumanBodyModel) EDSD TVB k 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