SCT2421STER

SILICON CONTENT TECHNOLOGY SCT2421 3.8V-40V Vin, 2A, High Efficiency Synchronous Step-down DCDC Converter with Programmable Frequency FEATURES DESCRIPTION     The SCT2421 is 2A synchronous buck converters with wide input voltage, ranging from 3.8V to 40V, which integrates an 160mΩ high-side MOSFET and an 80mΩ low-side MOSFET. The SCT2421, 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-40V Up to 2A Continuous Output Current 0.8V ±1% Feedback Reference Voltage Integrated 160mΩ High-Side and 80mΩ Low-Side Power MOSFETs Pulse Skipping Mode (PSM) with 25uA Quiescent Current in Sleep Mode 100ns Minimum On-time Programmable Internal Soft-start Time Fixed Switching Frequency 570kHz 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 The SCT2421 features programmable soft start time with 570kHz switching frequency. The converter allows power conversion from high input voltage to low output voltage with a minimum 100ns on-time of high-side MOSFET. It also supports Low Drop-Out LDO operation at low voltage difference from input to output condition. The SCT2421 is an Electromagnetic Interference (EMI) friendly buck converter with implementing optimized design for EMI reduction. The SCT2421 features Frequency Spread Spectrum FSS with ±6% jittering span of the switching frequency and modulation rate 1/512 of switching frequency to reduce the conducted EMI. APPLICATIONS        The SCT2421 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. 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 TYPICAL APPLICATION 100 BOOT VIN SW SS C6 FB VOUT C5 VIN GND SCT2421 EN COMP C1 C2 90 L1 R1 R3 C4 R2 Efficiency(%) C3 80 70 60 VIN=12V,VOUT=3.3V VIN=24V,VOUT=3.3V 50 VIN=24V, Vout=12V 40 0.001 0.01 0.1 1 Output Current(A) Efficiency For more information www.silicontent.com © 2019 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2421 1 SCT2421 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Revision 1.0: Production DEVICE ORDER INFORMATION PART NUMBER PACKAGE MARKING PACKAGE DISCRIPTION SCT2421STE 2421 8-Lead Plastic ESOP For Tape & Reel, Add Suffix R (e.g. SCT2421STER) 1) ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION Over operating free-air temperature unless otherwise noted(1) DESCRIPTION MIN MAX UNIT VIN, EN -0.3 42 V BOOT -0.3 46 V SW -0.3 42 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 SS 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. PIN FUNCTION BOOT 1 VIN 2 EN 3 SS 4 FB 5 COMP 6 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. Place a ceramic cap from this pin to ground to program soft-start time. An internal 3uA current source pulls SS pin to VCC. 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 8 Regulator switching output. Connect SW to an external power inductor 2 For more information www.silicontent.com © 2019 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2421 SCT2421 Thermal Pad 9 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. 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 40 40 125 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 RθJA RθJC THERMAL METRIC SOP-8L Junction to ambient thermal resistance(1) Junction to case thermal UNIT 42 resistance(1) °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 SCT2421 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 SCT2421. 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 ISHDN Input UVLO Threshold Hysteresis Shutdown current from VIN pin IQ Quiescent current from VIN pin VIN_UVLO TYP 3.8 VIN rising 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 3.5 400 1 MAX UNIT 40 V 3.7 V mV μA 3 25 μA 160 mΩ 80 mΩ Reference and Control Loop For more information www.silicontent.com © 2019 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2421 3 SCT2421 VREF Reference voltage of FB 0.792 GEA Error amplifier trans-conductance -2μA