RT6268GSP Richtek

RT6268 3.7A, 36V, 100kHz Asynchronous Step-Down Converter with Load Line Compensation General Description Features 1% High Accuracy Feedback Voltage The RT6268 is a high-efficiency, monolithic asynchronous 7V to 36V Input Voltage Range step-down DC/DC converter that can deliver up to 3.7A 3.7A Peak Output Current output current from a 7V to 36V input supply. The RT6268 s CC/CV Mode Control current mode architecture with internal compensation is Adjustable Load Line Compensation optimized for 5V car charger application over a wide range Short Circuit Protection of loads and output capacitors. Cycle-by-cycle current limit Integrated N-MOSFET Switches provides protection against shorted outputs and soft-start Current Mode Control eliminates input current surge during start-up. The RT6268 Fixed Frequency Operation : 100kHz also provides output over voltage protection output under Programmable Output Current Limit voltage protection and thermal shutdown protection. The 60m Internal Power MOSFET Switch low current (<3A) shutdown mode provides output Low EMI signature disconnect, enabling easy power management in battery- Up to 95% Efficiency powered systems. The RT6268 is available in a SOP-8 Cycle-by-Cycle Over Current Protection (Exposed Pad) package. Input Under Voltage Lockout Output Under Voltage Protection Ordering Information Thermal Shutdown Protection RT6268 Package Type SP: SOP-8(Exposed Pad-Option 2) Applications Lead Plating System USB Power Supplies G : Green (Halogen Free and Pb Free) Automotive Cigarette Lighter Adapters Note : Power Supply for Linear Chargers Richtek products are : DC/DC Converters with Current Limited RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. Pin Configurations Suitable for use in SnPb or Pb-free soldering processes. (TOP VIEW) Marking Information 8 VIN SW RT6268GSP : Product Number 2 7 BOOT GND GND RT6268 3 6 YMDNN : Date Code EN CSP 9 GSPYMDNN 4 FB 5 CSN SOP-8 (Exposed Pad) Simplified Application Circuit C BOOT L1 R C SENSE OUT V OUT D1 V IN VIN SW RT6268 R1 C BOOT GND IN R EN EN CSP R2 FB CSN Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS6268-00 September 2015 www.richtek.com 1RT6268 Functional Pin Description Pin No. Pin Name Pin Function Input Supply Voltage, 7V to 36V. Must bypass with a suitably large ceramic 1 VIN capacitor. Bootstrap for High-Side Gate Driver. Connect 0.1F or greater ceramic 2 BOOT capacitor from BOOT to SW pins. Enable Input Pin. A logic high enables the converter a logic low forces the 3 EN RT6268 into shutdown mode reducing the supply current to less than 3A. Attach this pin to VIN with a 100k pull up resistor for automatic startup. Feedback Input Pin. This pin is connected to the converter output. It is used to set the output of the converter to regulate to the desired value via an external 4 FB resistive voltage divider. For an adjustable output, an external resistive divider is connected to this pin. Current Sense Negative Input. It is used for load current limiting and load line 5 CSN drop compensation. Current Sense Positive Input. It is used for load current limiting and load line 6 CSP drop compensation. 7, Ground. The exposed pad must be soldered to a large PCB and connected to GND 9 (Exposed Pad) GND for maximum power dissipation. (Connect the exposed pad to Pin 7) 8 SW Switch Output -- Connect to external L-C filter and Schottky diode. Function Block Diagram EN VIN VCC Internal VCC Regulator VIBIAS EN V REF Oscillator Current Ramp Sense Foldback VCC Control BOOT OC UGATE Current Control GND UV&OV Comp SW Driver + - LGATE SS 2Meg Circuit Current 100mV Limit CSP + 80p 1p + - CSN 0.8V EA + - 1Meg 1Meg Line 10p Comp + EA - FB Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS6268-00 September 2015 2