SCT2450STER

SILICON CONTENT TECHNOLOGY SCT2450 Rev.1.5 3.8V-36V Vin, 5A, High Efficiency Synchronous Step-down DCDC Converter with Programmable Frequency FEATURES DESCRIPTION • • • • The SCT2450 is 5A synchronous buck converters with wide input voltage, ranging from 3.8V to 36V, which integrates a 45mΩ high-side MOSFET and a 20mΩ low-side MOSFET. The SCT2450, adopting the peak current mode control, supports the Pulse Skipping Modulation (PSM) with typical 25uA low quiescent current which assists the converter on achieving high efficiency at light load or standby condition. • • • • • • • • • • • Wide Input Range: 3.8V-36V Up to 5A Continuous Output Current 0.8V ±1% Feedback Reference Voltage Integrated 45mΩ High-Side and 20mΩ Low-Side Power MOSFETs Pulse Skipping Mode (PSM) with 25uA Quiescent Current in Sleep Mode 100ns Minimum On-time 4ms Internal Soft-start Time Adjustable Frequency 100KHz to 1.1MHz External Clock Synchronization Frequency Spread Spectrum (FSS) Modulation for EMI Reduction Precision Enable Threshold for Programmable Input Voltage Under-voltage Lock Out Protection (UVLO) Threshold and Hysteresis Low Dropout Mode Operation Derivable Inverting Voltage Regulator Over-voltage and Over-Temperature Protection Available in an ESOP-8 Package APPLICATIONS • • • • • • • Battery Pack Powered System - Cordless Power Tools, Cordless Home Appliance, Drone, Aero Modeling, GPS Tracker etc. Cigarette Lighter Adapters, Chargers LCD Display USB Type-C Power Delivery, USB Charging Industrial and Medical Distributed Power Supplies Optical Communication and Networking System Automotive System The SCT2450 features programmable switching frequency from 100 kHz to 1.1 MHz with an external resistor, which provides the flexibility to optimize either efficiency or external component size. The converter supports external clock synchronization with a frequency band from 100kHz to 1.1MHz. The SCT2450 allows power conversion from high input voltage to low output voltage with a minimum 100ns on-time of highside MOSFET. The SCT2450 is an Electromagnetic Interference (EMI) friendly buck converter with implementing optimized design for EMI reduction. The SCT2450 features Frequency Spread Spectrum FSS with ±6% jittering span of the 500kHz switching frequency and modulation rate 1/512 of switching frequency to reduce the conducted EMI. The SCT2450 offers cycle-by-cycle current limit and hiccup over current protection, thermal shutdown protection, output over-voltage protection and input voltage under-voltage protection. The device is available in an 8-pin thermally enhanced SOP-8 package. TYPICAL APPLICATION 100 Efficiency(%) 90 80 VIN=24V, VOUT=5V 70 VIN=24V, VOUT=3.3V VIN=12V, VOUT=5V 60 VIN=12V,VOUT=3.3V 50 0.001 0.01 0.1 1 10 Output Current (A)， Freq.=500KHz For more information www.silicontent.com © 2017 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2450 1 SCT2450 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Revision 1.0: Released to market Revision 1.1: Updated Functional Block Diagram Revision 1.2: Updated Related Parts Parameter Revision 1.3: Updated Description Revision 1.4: Updated Description Revision 1.5: Updated Table 3 DEVICE ORDER INFORMATION PART NUMBER PACKAGE MARKING PACKAGE DISCRIPTION SCT2450STE 2450 8-Lead Plastic ESOP 1) For Tape & Reel, Add Suffix R (e.g. SCT2430STER) ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION Over operating free-air temperature unless otherwise noted(1) DESCRIPTION MIN MAX UNIT VIN, EN -0.3 38 V BOOT -0.3 44 V SW -1 38 V BOOT-SW -0.3 6 V COMP, FB, RT/CLK -0.3 6 V Operating junction temperature TJ(2) -40 150 °C Storage temperature TSTG -65 150 °C (1) (2) BOOT 1 VIN 2 EN 3 RT/CLK 4 Thermal PAD 9 8 SW 7 GND 6 COMP 5 FB Figure 1. 8-Lead Plastic E-SOP Stresses beyond those listed under Absolute Maximum Rating may cause device permanent damage. The device is not guaranteed to function outside of its Recommended Operation Conditions. The IC includes over temperature protection to protect the device during overload conditions. Junction temperature will exceed 150°C when over temperature protection is active. Continuous operation above the specified maximum operating junction temperature will reduce lifetime. PIN FUNCTIONS NAME NO. BOOT 1 VIN 2 EN 3 2 PIN FUNCTION Power supply bias for high-side power MOSFET gate driver. Connect a 0.1uF capacitor from BOOT pin to SW pin. Bootstrap capacitor is charged when low-side power MOSFET is on or SW voltage is low. Input supply voltage. Connect a local bypass capacitor from VIN pin to GND pin. Path from VIN pin to high frequency bypass capacitor and GND must be as short as possible. Enable pin to the regulator with internal pull-up current source. Pull below 1.1V to disable the converter. Float or connect to VIN to enable the converter. The tap of resistor divider from VIN to GND connecting EN pin can adjust the input voltage lockout threshold. For more information www.silicontent.com © 2017 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2450 SCT2450 RT/CLK 4 FB 5 COMP 6 Set the 20internal oscillator clock frequency or synchronize to an external clock. Connect a resistor from this pin to ground to set switching frequency. An external clock can be input directly to the RT/CLK pin. The internal oscillator synchronizes to the external clock frequency with PLL. If detected clocking edges stops, the operation mode automatically returns to resistor programmed frequency. Inverting input of the trans-conductance error amplifier. The tap of external feedback resistor divider from the output to GND sets the output voltage. The device regulates FB voltage to the internal reference value of 0.8V typical. Error amplifier output. Connect to frequency loop compensation network. GND 7 Ground SW Thermal Pad 8 Regulator switching output. Connect SW to an external power inductor Heat dissipation path of die. Electrically connection to GND pin. Must be connected to ground plane on PCB for proper operation and optimized thermal performance. 9 RECOMMENDED OPERATING CONDITIONS Over operating free-air temperature range unless otherwise noted PARAMETER DEFINITION VIN VOUT TJ Input voltage range Output voltage range Operating junction temperature MIN MAX UNIT 3.8 0.8 -40 36 36 125 V V °C MIN MAX UNIT -2 +2 kV -0.5 +0.5 kV ESD RATINGS PARAMETER DEFINITION Human Body Model(HBM), per ANSI-JEDEC-JS-001-2014 specification, all pins(1) Charged Device Model(CDM), per ANSI-JEDEC-JS-0022014 specification, all pins(2) VESD (1) JEDEC document JEP155 states that 500V HBM allows safe manufacturing with a standard ESD control process. (2) JEDEC document JEP157 states that 250V CDM allows safe manufacturing with a standard ESD control process. THERMAL INFORMATION PARAMETER THERMAL METRIC RθJA Junction to ambient thermal resistance(1) RθJC Junction to case thermal resistance(1) SOP-8L UNIT 42 °C/W 45.8 (1) SCT provides RθJA and RθJC numbers only as reference to estimate junction temperatures of the devices. RθJA and RθJC are not a characteristic of package itself, but of many other system level characteristics such as the design and layout of the printed circuit board (PCB) on which the SCT2450 is mounted, thermal pad size, and external environmental factors. The PCB board is a heat sink that is soldered to the leads and thermal pad of the SCT2450. Changing the design or configuration of the PCB board changes the efficiency of the heat sink and therefore the actual RθJA and RθJC. ELECTRICAL CHARACTERISTICS VIN=24V, TJ=-40°C~125°C, typical value is tested under 25°C. SYMBOL PARAMETER TEST CONDITION Power Supply VIN Operating input voltage VIN_UVLO MIN TYP MAX 36 V 3.5 400 3.7 V mV 3.8 Input UVLO Threshold Hysteresis VIN rising For more information www.silicontent.com © 2017 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2450 UNIT 3 SCT2450 SYMBOL PARAMETER TEST CONDITION ISHDN Shutdown current from VIN pin IQ Quiescent current from VIN pin EN=0, no load EN floating, no load, nonswitching, BOOT-SW=5V Power MOSFETs RDSON_H High-side MOSFET on-resistance RDSON_L MIN VBOOT-VSW=5V Low-side MOSFET on-resistance Reference and Control Loop VREF Reference voltage of FB 0.792 TYP MAX 1 3 UNIT μA 25 μA 45 mΩ 20 mΩ 0.8 0.808 V GEA Error amplifier trans-conductance -2μA