SC2440 2.5 MHz Dual Switching Regulator with Integrated 2A Switches POWER MANAGEMENT Description Features The SC2440 is an adjustable frequency dual current- Up to 2.5 MHz/Channel Programmable Switching mode switching regulator with 2A integrated switches. Frequency Its high frequency operation allows the use of small Fixed Frequency Current-mode Control inductors and capacitors, resulting in very compact power Wide Input Voltage Range 2.8V to 20V supplies. The SC2440 is suitable for next generation XDSL Out of Phase Switching Reduces Ripple modems requiring operating frequencies in excess of 1.5 Cycle-by-cycle Current-limiting MHz. The two channels operate at 180 out of phase Independent Shutdown/soft-start Pins for reduced input voltage ripples. Separate soft start/ Independent Hiccup Overload Protection shutdown pins allow independent control and output Independent Power-Good Indicators sequencing for latch-up prevention. The SC2440 can also Two 2A Integrated Switches be externally synchronized up to 2.5 MHz per channel. External Synchronization Thermal Shutdown Current-mode PWM control allows fast transient response with simple loop compensation. Cycle-by-cycle Thermally Enhanced 16-pin TSSOP Package current limiting and hiccup overload protection reduce Applications power dissipation during overload. XDSL and Cable Modems Set-up Boxes Point of Load Applications CPE Equipment DSP Power Supplies Disk Drives Typical Application Circuit R6 100K D3 FB1 Efficiency vs Load Current PGOOD1 BOOST1 C5 R5 C2 1N4148 95 0.1 F 15.4K C6 470pF L1 OUT1 V = 12V IN V = 5V OUT2 COMP1 SW1 90 3.3 H R1 3.3V/2A C7 10pF VIN D1 23.3K SS1 12V 85 SC2440 UPS120 C1 22nF C15 10 F SYNC R2 80 IN 10K R9 10 F V = 3.3V ROSC OUT1 C10 15K D2 75 UPS120 SS2 C9 L2 OUT2 22nF 70 SW2 COMP2 4.4 H 5V/2A C8 C4 10pF R7 65 R3 0.1 F D4 40.2K 24.3K 220pF FB2 BOOST2 C3 60 10 F 1N4148 R8 R4 GND PGOOD2 55 10K 100K 50 0 0.5 1 1.5 2 L1: Sumida CR43 Load Current (A) L2: F alco D04012 Figure 1. 1.3MHz 12V to 3.3V and 5V Step-down Converter Revision: March 5, 2007 1 www.semtech.com Efficiency (%)SC2440 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. Plarameter Sxymbo Msa Unit IVnput Voltage -V0.3 to 20 IN BVoost Pin 4V0 BST BVoost Pin Above SW -V 2V0 BST SW PVGOOD Pin Voltage V V PGOOD IN SVS Pins 3V SS FVB Pins -0.3 to V V FB IN SIYNC Pin Current 5Am SYNC SW Voltage V -0.6 to V V SW IN V +1.5 IN SVW Transient Spikes (<10ns Duration) V SW -2.5 OTperating Ambient Temperature Range -C40 to 85 A Thermal Resistance Junction to Ambient 4W5 C/ JA MTaximum Junction Temperature 1C50 J STtorage Temperature Range -C65 to +150 STG LTead Temperature (Soldering)10 sec 3C00 LEAD Electrical Characteristics Unless specified: -40C < T < 85C, -40C < T < 105C, R = 12.1K , V = 0, V = 5V, V = 8V A J OSC SYNC IN BOOST Psarameter Cnondition Mpi Txy Msa Unit V Start Voltage 22.4528.6 2V.7 IN V Start Hysteresis 7V5 m IN Qnuiescent Current N3ot switching, PGOOD Ope 33. 4A. m SVhutdown Current = V=80V, PGOOD Open 306A SS1 SS2 Feedback Voltage 00.98010.001V.02 Feedback Voltage Line V=53V to 20V 0V.00 %/ IN Regulation FVB Pin Input Bias Current = 1V, V=51.5V -01 -A3 n FB COMP -1 Error Amplifier Transconductance 280 Error Amplifier Open-loop Gain 5B3 d CVOMP Source Current = 0.8V, V=01.5V 2A FB COMP CVOMP Sink Current = 1.2V, V=01.5V 2A FB COMP COMP Pin to Switch Current Gain 5V.7 A/ 2005 Semtech Corp. 2 www.semtech.com