SC4503 1.3MHz Step-Up Switching Regulator with 1.4A Switch POWER MANAGEMENT Features Description Features The SC4503 is a 1.3MHz current-mode step-up switch- Low Saturation Voltage Switch: 260mV at 1.4A ing regulator with an integrated 1.4A power transistor. 1.3MHz Constant Switching Frequency Its high switching frequency allows the use of tiny sur- Peak Current-mode Control face-mount external passive components. The SC4503 Internal Compensation features a combined shutdown and soft-start pin. The Programmable Soft-Start optional soft-start function eliminates high input current Input Voltage Range From 2.5V to 20V and output overshoot during start-up. The internal com- Output Voltage up to 27V pensation network accommodates a wide range of volt- Uses Small Inductors and Ceramic Capacitors age conversion ratios. The internal switch is rated at 34V Low Shutdown Current (< 1A) making the device suitable for high voltage applications Low Pro le 5-Lead TSOT-23 and 8-Lead 2X2mm such as Boost and SEPIC. MLPD-W packages Fully WEEE and RohS compliant The SC4503 is available in low-pro le 5-Lead TSOT-23 and 8-Lead 2X2mm MLPD-W packages. The SC4503s low shutdown current (< 1A), high frequency operation Applications and small size make it suitable for portable applications. Local DC-DC Converters TFT Bias Supplies XDSL Power Supplies Medical Equipment Digital Cameras Portable Devices White LED Drivers Typical Application Circuit Typical Application Circuit D1 L1 Efficiency vs Load Current VIN VOUT 95 12V, 0.5A 5V 4.7H 1.3MHz 10BQ015 90 5 1 C4 R1 85 IN SW 15pF 432k 80 SC4503 C1 C2 1F 3 75 4 4.7F ON OFF SHDN/SS FB 70 GND R2 65 2 49.9k 60 V = 12V OUT 55 50 C1: Murata GRM188R61A105K 0.001 0.010 0.100 1.000 C2: Murata GRM21BR61C475K Load Current (A) L1: Sumida CDC5D23B-4R7 Figure 1(b). Ef ciency of the 5V to 12V Boost Converter Figure 1(a). 5V to 12V Boost Converter May 4, 2007 www.semtech.com 1 Efficiency (%)SC4503 POWER MANAGEMENT Absolute Maximum Ratings Absolute Maximum Ratings Exceeding the speci cations below may result in permanent damage to the device or device malfunction. Operation outside of the parameters speci ed in the Electrical Characteristics section is not recommended. Parameter Symbol Maximum Units Supply Voltage V -0.3 to 20 IN SW Voltage V -0.3 to 34 SW V FB Voltages V -0.3 to V +0.3 FB IN SHDN/SS Voltage V -0.3 to V +1 SHDN IN Thermal Resistance Junction to Ambient (TSOT - 23) 191* C/W JA Thermal Resistance Junction to Ambient (2X2mm MLPD-W) 78* C/W JA Maximum Junction Temperature T 150 J Storage Temperature Range T -65 to +150 STG C Lead Temperature (Soldering)10 sec (TSOT - 23) T 260 LEAD Peak IR Re ow Temperature (2X2mm MLPD-W) T 260 IR ESD Rating (Human Body Model) ESD 2000 V *Calculated from package in still air, mounted to 3 x 4.5, 4 layer FR4 PCB with thermal vias under the exposed pad as per JESD51 standards. Electrical Characteristics Unless speci ed: V = V = 3V, -40C < T = T < 85C IN SHDN/SS A J Parameter Conditions Min Typ Max Units Under-Voltage Lockout Threshold 2.2 2.5 Maximum Operating Voltage 20 V Feedback Voltage 1.225 1.250 1.275 Feedback Line Voltage Regulation 2.5V < V < 20V 0.02 %/V IN FB Pin Bias Current -25 -50 nA Switching Frequency 1.15 1.30 1.55 MHz Minimum Duty Cycle 0 % Maximum Duty Cycle 86 90 Switch Current Limit 1.4 1.9 2.5 A Switch Saturation Voltage I = 1.4A 260 430 mV SW Switch Leakage Current V = 5V 0.01 1 A SW V Quiescent Supply Current V = 2V, V = 1.5V (not switching) 0.8 1.1 mA IN SHDN/SS FB V Supply Current in Shutdown V = 0 0.01 1 A IN SHDN/SS 2007 Semtech Corp. 2 www.semtech.com