SC4501 2Amp, 2MHz Step-Up Switching Regulator with Soft-Start POWER MANAGEMENT Features Description The SC4501 is a high-frequency current-mode step-up Low saturation voltage switch: 220mV at 2A switching regulator with an integrated 2A power transis- Constant switching frequency current-mode control tor. Its high switching frequency (programmable up to Programmable switching frequency up to 2MHz 2MHz) allows the use of tiny surface-mount external pas- Soft-Start function sive components. Programmable soft-start eliminates high Input voltage range from 1.4V to 16V inrush current during start-up. The internal switch is rated Output voltage up to 32V at 32V making the converter suitable for high voltage ap- Low shutdown current plications such as Boost, SEPIC and Flyback. Adjustable undervoltage lockout threshold Small low-profile thermally enhanced packages The operating frequency of the SC4501 can be set with an external resistor. The ability to set the operating frequency Applications gives the SC4501 design flexibilities. A dedicated COMP pin allows optimization of the loop response. The SC4501 Flat screen LCD bias supplies is available in thermally enhanced 8-Pin MSOP and 10-pin TFT bias supplies MLPD packages. XDSL power supplies Medical equipment Digital video cameras Portables devices White LED power supplies Typical Application Circuit D1 L1 VIN VOUT 12V, 0.7A 5V 10BQ015 R1 6 5 174K Efficiency IN SW 3 95 OFF ON 2 SHDN FB 10.5H, 700KHz 4.7H, 1.4MHz C2 C1 SC4501 90 10F 2.2F 8 1 SS COMP 85 R2 GND ROSC R3 20K C3 4 7 C6 80 47nF R4 3.3H, 2MHz C4 75 70 All Capacitors are Ceramic. 65 MSOP-8 Pinout 60 f / MHz R / K R / K C / pF C / pF L / H 3 4 4 6 1 55 V = 5V IN V = 12V OUT 0.7 22.1 22.1 2200 - 10.5 (Falco D08019) 50 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 1.35 30.9 9.31 820 - 4.7 (Falco D08017) Load Current (A) 2 63.4 4.75 470 22 3.3 (Coilcraft DO1813P) Figure 1(a). 5V to 12V Boost Converter. Figure 1(b). Efficiencies of 5V to 12V Boost Converters at 700KHz, 1.4MHz and 2MHz. Revision: October 25, 2005 1 www.semtech.com Rev.1 March 24, 2011 Efficiency (%)SC4501 POWER MANAGEMENT Absolute Maximum Rating 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 Symbol Typ Units Supply Voltage V -0.3 to 18 V IN SW Voltage V -0.3 to 32 V SW FB Voltages V -0.3 to 2.5 V FB SHDN Voltage V -0.3 to V + 1 V SHDN IN Operating Temperature Range T -40 to +85 C A Thermal Resistance Junction to Ambient (MSOP-8) 40 JA C/W Thermal Resistance Junction to Ambient (MLPD-10) 40 JA Maximum Junction Temperature T 160 C J Storage Temperature Range T -65 to +150 C STG Lead Temperature (Soldering)10 sec T 260 C LEAD ESD Rating (Human Body Model) ESD 2000 V Electrical Characteristics Unless specified: V = 2V, SHDN = 1.5V, R = 7.68k, -40C < T = T < 85C OSC IN A J Parameter Test Conditions Min Typ Max Unit Undervoltage Lockout Threshold 1.3 1.4 V Maximum Operating Voltage 16 V T = 25C 1.224 1.242 1.260 V A Feedback Voltage -40C < T < 85C 1.217 1.267 V A Feedback Voltage Line 1.5V < V < 16V 0.01 % IN Regulation FB Pin Bias Current 40 80 nA 1 Error Amplifier Transconductance 60 Error Amplifier Open-Loop Gain 49 dB COMP Source Current V = 1.1V 5 A FB COMP Sink Current V = 1.4V 5 A FB V Quiescent Supply Current V = 1.5V, V = 0 ( Not Switching ) 1.1 1.6 mA IN SHDN COMP V Supply Current in Shutdown V = 0 10 18 A IN SHDN Switching Frequency 1.27 1.5 1.77 MHz Maximum Duty Cycle 85 90 % Minimum Duty Cycle 0% Switch Current Limit 2 2.8 A Switch Saturation Voltage I = 2A 220 350 mV SW www.semtech.com 2005 Semtech Corp.2011 2