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SC4508A Dataheets PDF



Part Number SC4508A
Manufacturers Semtech Corporation
Logo Semtech Corporation
Description Buck or Buck-Boost Current Mode Controller
Datasheet SC4508A DatasheetSC4508A Datasheet (PDF)

Buck or Buck-Boost (Inverting) Current Mode Controller POWER MANAGEMENT Description The SC4508A is a low voltage current mode switching regulator controller that drives a P-channel power MOSFET with programmable switching frequency. It can be configured in either buck or buck boost (inverting) converters. The converters can be operated from 2.7V to 15V input voltage range. The typical operating supply current is 3mA and a shutdown pin allows the user to turn the controller off reducing it to les.

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Buck or Buck-Boost (Inverting) Current Mode Controller POWER MANAGEMENT Description The SC4508A is a low voltage current mode switching regulator controller that drives a P-channel power MOSFET with programmable switching frequency. It can be configured in either buck or buck boost (inverting) converters. The converters can be operated from 2.7V to 15V input voltage range. The typical operating supply current is 3mA and a shutdown pin allows the user to turn the controller off reducing it to less than 200µA. The output voltage can adjusted by external resistor diwww.DataSheet4U.com vider. The switching frequency is programmable up to 1.5MHz, allowing small inductor and capacitor values to minimize PCB space. The operating current level is programmable via an external sense resistor. Accessible reference voltage allows users to make output voltage as low as they want. SC4508A Features ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ Wide input voltage range 2.7V to 15V Programmable output voltage Programmable switching frequency up to 1.5MHz Buck or buck boost (inverting) configuration Current mode control with slope compensation Very low quiescent current in shutdown mode Accessible reference voltage Hiccup mode after 32 cycle-by-cycle OCP 4mm x 4mm MLPQ-12 lead free package. This product is fully WEEE and RoHS compliant Applications ‹ ‹ ‹ ‹ ‹ ‹ ‹ Low power point of use converters Single or multiple output low power converters Positive and/or negative output voltage DSL cards Graphic cards I/O cards Negative bias supplies Typical Application Circuits Vin Vin V+ V+ VREF VREF CS FB+ OUT FB- FB+ FB- SC4508A SC4508A CS COMP Vout SS/EN GND OSC COMP OUT Vout SS/EN GND OSC Revision: July 25, 2007 1 www.semtech.com SC4508A 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 VDD to GND SS/EN to GND(1) FB+, FB-, COMP, OSC to GND VREF Current www.DataSheet4U.com Thermal Resistance, Symbol Maximum -0.3 to 16 3.2 5 1 Units V V V mA °C/W °C/W °C °C °C Junction to Ambient θJ A θJ C TSTG TJ TPKG 48 3 -60 to +150 -40 to +150 260 Thermal Resistance, Junction to Case Storage Temperature Range Junction Temperature Range Peak IR Reflow Temperature 10 - 40s Note: (1) Voltage from internal circuitry could be higher than 3.2V. See Application Information, Soft-Start section. Electrical Characteristics Unless specified: VDD = 12V, VFB+ = VREF, VFB- = 0, OUT = open, CVDD = 1uF, CSS/EN = 0.1uF, COSC = 330pF. TA = TJ = -40°C to 125°C Parameter Pow er Supply Input Voltage Range Quiescent Current Operating Current Undervoltage Lockout Start Threshold UVLO Hysteresis Oscillator Frequency Range Frequency Charge Current Error Amplifier Feedback Input Voltage Offset Voltage Input Bias Current Transconductance Output Source or Sink Current  2007 Semtech Corp. Test Conditions Min Typ Max Unit 2.7 SS/EN = low SS/EN = high, No load 200 3 15 500 V µA mA VDD rising 2.35 2.5 100 2.55 V mV 100 450 500 100 1500 550 KHz KHz µA -0.2 2 100 5 50 2 0.7 V mV 300 nA mS µA www.semtech.com 100 SC4508A POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified: VDD = 12V, VFB+ = VREF, VFB- = 0, OUT = open, CVDD = 1uF, CSS/EN = 0.1uF, COSC = 330pF. TA = TJ = -40°C to 125°C Parameter PWM Comparator Maximum Duty Cycle Test Conditions Min Typ Max Unit C = 1.5nF, 100kHz C = 100pF, 1.5MHz 97 95 200 63 50 % % nS mV/Ts ns Minimum On Time www.DataSheet4U.com Slope Compensation Delay to Output VREF Reference Output Voltage Output Voltage Output Current Line Regulation Load Regulation Soft Start/Enable/Shutdow n Charge Current VSS/EN > 0.9V VSS/EN < 0.9V Discharge Current Enable Logic Voltage SHDN Logic Voltage Current Limit Cycle by Cycle Threshold Consecutive Overcurrent Clock Cycles before Auto Restart Shutdown Delay to Output Output Gate Drive On-Resistance(H) Gate Drive On-Resistance(L) Gate Drive On-Resistance(H) Gate Drive On-Resistance(L) Rise Time Fall Time  2007 Semtech Corp. 0.4925 TA = 25°C, VDD = 5V 0.496 0.5 0.5 0.5075 0.504 1 V V mA mV mV VDD = 2.7 to 15V, IVREF = 1mA VDD = 5V, IVREF = 0 to 1mA 5 2 10 4 20 10 12 2 0.35 µA mA V V V D D = 5V 90 110 32 130 mV 50 nS 8 8 V D D = 5V V D D = 5V COUT = 1000pF COUT = 1000pF 3 Ohm Ohm Ohm Ohm nS nS www.semtech.com 15 15 20 20 SC4508A POWER MANAGEMENT Pin Configuration TOP VIEW VDD OSC COMP Ordering Information Part Number SC4508AMLTRT(2) SC4508ABUCKEVB SC4508ABUCK-BOOSTEVB P ackag e (1) MLPQ -12 Evaluation Board Evaluation Board 12 OUT www.DataSheet4U.com 11 10 9 8 7 FB+ FBPGND 1 2 3 4 5 6 CS Notes: (1) Only available in tape and reel packaging. A reel contains 3000 devices. (2) Lead free product. This product is fully WEEE and RoHS compliant. SS/EN VREF NC AGND (MLPQ - 12, 4mm x 4mm) Pin Descriptions Pin # 1 2 3 Pin Name OUT CS SS/E.


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