RT9721A/B 80m, 500mA High-Side Power Switches with Flag General Description Features zz z zz Compliant to USB Specifications The RT9721A/B are low voltage, single N-MOSFET high- zz z zz Built-In N-MOSFET side power switches, optimized for self-powered and bus- Typical R : 80m DS(ON) powered Universal Serial Bus (USB) applications. The zz z zz Output Can Be Forced to Higher Than Input (Off- RT9721A/B series provides a charge pump circuitry to drive State) the internal MOSFET switch the switch s low R , DS(ON) zz z zz Low Supply Current : 80m, meets USB voltage drop requirements and a flag 50A Typical at Switch On State output is available to indicate fault conditions to the local 0.1A Typical at Switch Off State USB controller. zz z zz Guaranteed 500mA Continuous Load Current Additional features include soft-start to limit inrush current zz z zz Wide Input Voltage Ranges : 2.5V to 5.5V during plug-in, thermal shutdown to prevent catastrophic zz z zz Open-Drain Fault Flag Output switch failure from high-current loads, under-voltage lockout zz z zz Hot Plug-In Application (Soft-Start) (UVLO) to ensure that the device remains off unless there zz z zz 2.15V Typical Under-Voltage Lockout (UVLO) is a valid input voltage present. The maximum current is zz z zz Current Limiting Protection limited to typically 750mA in dual ports in accordance with zz z zz Thermal Shutdown Protection the USB power requirements, lower quiescent current as zz z zz Reverse Current Flow Blocking (no body diode) 50uA making this device ideal for portable battery-operated zz z zz UL ApprovedE219878 equipment. zz z zz RoHS Compliant and Halogen Free The RT9721A is designed without output auto-discharge Applications function and RT9721B is designed with output auto- z USB Bus/Self Powered Hubs discharge function. z USB Peripherals The RT9721A/B are available in SOT-23-5 package z Notebook, Motherboard PCs requiring minimum board space and smallest components. Pin Configurations Ordering Information (TOP VIEW) RT9721 Package Type VOUT FLG B : SOT-23-5 5 4 Lead Plating System 23 G : Green (Halogen Free and Pb Free) Output Discharge Function VIN GND EN A : Without Auto-Discharge Function SOT-23-5 B : With Auto-Discharge Function Note : Marking Information Richtek products are : For marking information, contact our sales representative RoHS compliant and compatible with the current require- directly or through a Richtek distributor located in your ments of IPC/JEDEC J-STD-020. area. Suitable for use in SnPb or Pb-free soldering processes. DS9721A/B-02 April 2011 www.richtek.com 1+ RT9721A/B Typical Application Circuit Pull-Up Resistor (10k to 100k) USB Controller 1 4 Supply Over -Current FLG VIN Voltage 5V C IN RT9721A/B 1F 5 VOUT Chip Enable V 3 BUS EN D+ C OUT 150F GND 10F D- 2 GND Ferrite Beads Data Functional Pin Description Pin No. Pin Name Pin Function 1 VIN Switch Input Voltage. 2 GND Ground. 3 Chip Enable (Active High). EN 4 Open-Drain Fault Flag Output. FLG 5 VOUT Switch Output Voltage. Function Block Diagram VIN EN Bias UVLO Current Limiting Gate Charge Oscillator Control Pump Output Voltage VOUT Detection Thermal Protection Auto Discharge RT9721B Only FLG Delay GND www.richtek.com DS9721A/B-02 April 2011 2