SCT2280FPAR

SILICON CONTENT TECHNOLOGY SCT2280 18V Vin, 8A, High Efficiency Synchronous Step-down DCDC Converter FEATURES DESCRIPTION     The SCT2280 is a high efficiency synchronous stepdown DC-DC converter with 4.5V-18V input voltage range and adjustable output voltage down to 0.6V. It offers a small saving 2mmx3mm QFN package that supplies continuous 8A output current. The device fully integrates high-side and low-side power MOSFETs with 25mΩ/12mΩ on-resistance to minimize the conduction loss.        Wide 4.5V-18V Input Voltage Range 0.6V-7V Output Voltage Range 8A Continuous Output Current Integrated 25mΩ/12mΩ Rdson of HS/LS Power MOSFETs Fixed 1ms Soft-start Time Selectable 400KHz, 800KHz and 1.2MHz Switching Frequencies Selectable PFM, USM and PWM Operation Modes Cycle-by-Cycle Current Limiting Output Over-Voltage Protection Over-Temperature Protection Available in a QFN 12-leads 2mmx3mm Package APPLICATIONS      High End DTV Set-top Box, XDSL Modem, Personal Video Recorders Server, Cloud-Computing, Storage Telecom & Networking, Small-cell Base Stations, Point-of-Load (POL) IPCs, Factory Automation, PLC, Test Measurement The SCT2280 adopts a Constant On-Time (COT) control to provide fast transient response and easy loop stabilization. The switching clock frequency can be selected from 400KHz, 800KHz and 1.2MHz for optimization of the filter size and output voltage ripple. The device offers fixed 1ms soft start to prevent inrush current during the startup of output voltage ramping. Power Good with open drain output signals that the output voltage is within regulation. The SCT2280 has the MODE pin to select Pulse Frequency Modulation (PFM) operation mode to achieve the light load power save, or Ultrasonic Mode (USM) to keep the switching frequency above audible frequency areas during light-load or no-load conditions, or the PWM mode to achieve the small output ripple. Full protection includes over current protection, undervoltage protection, and thermal shutdown. The converter requires a minimum number of external components and is available in a QFN- 12 (2mmx3mm) package. TYPICAL APPLICATION 90 VIN C3 C1 ON/OFF PG R3 80 BST EN MODE FSEL PG L1 70 VOUT SW C4 R1 VOUT FB VCC C2 R2 AGND PGND Efficiency (%) VIN 60 50 40 30 VIN=12, VOUT=1V,PFM 20 VIN=12, VOUT=1V, USM 10 VIN=12V,VOUT=1V,FPWM 0 0.01 0.1 1 10 Output Current (A) 4.5V-18V, Synchronous Buck Converter Vin=12V, Vout=1V, fsw=800kHz For more information www.silicontent.com © 2018 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2280 1 SCT2280 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Revision 1.0: Release to Market Revision 1.3: Update TYPICAL CHARACTERISTICS DEVICE ORDER INFORMATION PART NUMBER PACKAGE MARKING PACKAGE DISCRIPTION SCT2280FPA 2280 12-Lead 2mm×3mm Plastic QFN For Tape & Reel, Add Suffix R (e.g. SCT2280FPAR). 1) ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION Over operating free-air temperature unless otherwise noted(1) DESCRIPTION MIN MAX UNIT VIN, VEN -0.3 19 V VBST VSW0.3 VSW -1 VMODE -0.3 VST+ 6 VIN+ 0.3 6.5 VFB -0.3 6.5 V VSEL -0.3 6.5 V VVOUT -0.3 6.5 V V V V VPG -0.3 6.5 V Operating junction temperature TJ(2) -40 125 °C Storage temperature TSTG -65 150 °C (1) (2) Figure 1. 12-Lead Plastic QFN ( Top view: 2mmx3mm) 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. VIN 1 PGND 2 PG 3 FSEL 4 2 PIN FUNCTION Input voltage. Decouple the input rail with at least 0.1uF input ceramic capacitor. Place the capacitor as close as to VIN and PGND pins as possible. Use wide PCB traces and multiple vias to make the connection. SCT2280 is a high efficiency power converter with 2-3ns fast turning on and turning off power MOSFETs for the best efficiency. If not placing the input capacitor close to VIN and GND pin, the voltage spike caused by trace parasitic inductance might EOS damage the device. Power ground. Using wide PCB traces and multiple vias large enough to handle the load current. Power good open-drain output. PG is high if the output voltage is higher than 95% or lower than 105% of the nominal voltage. Switching frequency selection. Connecting to ground sets clock frequency to 400KHz. Floating sets clock frequency to 800KHz. Connecting to VCC sets clock frequency to 1.2MHz. For more information www.silicontent.com © 2018 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2280 SCT2280 VOUT 5 MODE 6 SW 7 BST 8 VCC 9 AGND 10 FB 11 EN 12 VOUT is used to sense the output voltage of the buck regulator. Connect VOUT to the output capacitor of the regulator directly. Keep the VOUT sensing trace far away from the SW node. VIAs should also be avoided on the VOUT sensing trace. A trace larger than 25mil is required. PFM, USM or FCCM mode selection. Connect the pin to VCC to force the device in Forced Continuous Current Modulation (FCCM) operation mode. Ground the pin to operate the device in Pulse Frequency Modulation (PFM) mode without Ultrasonic Mode (USM). Floating the pin to operate the device in PFM with USM. Connect SW to the inductor and bootstrap capacitor. SW is driven up to VIN through the high-side power MOSFET during on-time. The inductor current drives SW to negative voltage through low-side power MOSFET during off-time. Use wide and short PCB traces to make the connection. Keep the SW pattern area minimized. Bootstrap. Must connect a 0.1uF capacitor or greater between SW and BST to form a floating supply across the gate driver of high-side power MOSFET. Internal VCC LDO output. The driver and control circuits are powered by VCC. Decouple with 1µF ceramic capacitor placed as close to VCC as possible. Signal logic ground. AGND is the Kelvin connection to PGND. Feedback voltage Input. Connect FB to the tap of a resistor divider from output voltage to AGND to set up output voltage. The device regulates FB to the internal reference value of 0.6V typical. Enable logic input. EN is a digital input that controls the converter on or off. EN high turns on the device and EN low turns off the device. Connecting to VIN with a 100kΩ pull-up resistor can enable the device. Floating EN pin automatically starts up the converter. 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 4.5 0.6 -40 18 7 125 V V °C MIN MAX UNIT -2 +2 kV -0.5 +0.5 kV ESD RATINGS PARAMETER VESD DEFINITION Human Body Model (HBM), per ANSI-JEDEC-JS-0012014 specification, all pins (1) Charged Device Model (CDM), per ANSI-JEDEC-JS-0022014specification, all pins (1) (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 QFN-12L RθJA Junction to ambient thermal resistance (1) 70 RθJC Junction to case thermal resistance 15 (1) UNIT °C/W (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 SCT2280 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 SCT2280. Changing the design or configuration of the PCB board changes the efficiency of the heat sink and therefore the actual RθJA and RθJC. For more information www.silicontent.com © 2018 Silicon Content Technology Co., Ltd. All Rights Reserved Product Folder Links: SCT2280 3 SCT2280 ELECTRICAL CHARACTERISTICS VIN=12V, TJ=-40°C~125°C, typical value is tested under 25°C. SYMBOL PARAMETER TEST CONDITION Power Supply and Output VIN Operating input voltage MIN TYP MAX 4.25 270 1 4.45 4.5 18 V ISD Vin UVLO rising threshold VIN UVLO Hysteresis Shutdown current IQ Quiescent current from VIN VCC VCC internal LDO regulator voltage EN=0, Measured on VIN pin EN=2V, Vout=5V, No load, No switching. Measured on VIN pin. IVCC=0mA VCC_LR VCC internal LDO load regulation IVCC=5mA 0.5 % IVCC_LIM VCC internal LDO current limit VCC short to ground 27 mA VINUVLO VINUVLO HYS 4 UNIT 3 130 4.75 5 V mV uA uA 5.25 V Reference and Control Loop VREF Reference voltage of FB 4.5V