RT8474AGSP Richtek

RT8474A High Voltage Buck LED Driver with Open Detection General Description Features High Voltage : V Up to 50V, V Up to 50V IN OUT The RT8474A is a current-mode LED driver supporting wide Built-In 2A Power Switch input voltage range from 4.5V to 50V and output voltage Current-Mode PWM Control up to 50V. With internal 500kHz operating frequency, the 500kHz Fixed Switching Frequency size of the external PWM inductor and input/output Analog or PWM Control Signal for LED Dimming capacitors can be minimized. High efficiency is achieved Internal Soft-Start to Avoid Inrush Current by a 100mV current sensing control. LED dimming control Adjustable OVP for LED Open Protection can be done from either analog or PWM signal. The Under-Voltage Lockout RT8474A provides an internal soft-start function to avoid Thermal Shutdown inrush current and thermal shutdown to prevent the device RoHS Compliant and Halogen Free from overheat. The RT8474A is available in the SOP-8 (Exposed pad) Applications package. Desk Lights and Room Lighting Industrial Display Backlight Ordering Information RT8474A Package Type Marking Information SP : SOP-8 (Exposed-Option 2) RT8474AGSP : Product Number Lead Plating System RT8474A YMDNN : Date Code G : Green (Halogen Free and Pb Free) GSPYMDNN Note : Richtek products are : RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Simplified Application Circuit D1 V IN C1 RT8474A R SENSE ISP VCC Analog Dimming ISN or PWM Dimming C4 R4 CTL VC L1 R3 SW R1 R2 CREG OVP C2 GND C3 Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS8474A-02 December 2013 www.richtek.com 1RT8474A Pin Configurations (TOP VIEW) 8 VCC CREG 2 7 ISP SW GND 3 6 ISN CTL 9 4 OVP 5 VC SOP-8 (Exposed Pad) Functional Pin Description Pin No. Pin Name Pin Function Supply Voltage Input. For good bypass, connect a low ESR capacitor 1 VCC between this pin and GND. 2 ISP Positive Current Sense Input. Negative Current Sense Input. Voltage threshold between ISP and ISN is 3 ISN 100mV. 4 OVP Over-Voltage Protection Sense Input. 5 VC Compensation Node for Current Loop. Analog Dimming Control Input. Effective programming range is 0.2V to 6 CTL 1.2V. 7 SW Switch Node of the PWM Converter. Regulator Output for Internal Circuit. Place a 1F capacitor to stabilize the 8 CREG 5V output regulator. Ground. The exposed pad must be soldered to a large PCB and connected 9 (Exposed Pad) GND to GND for maximum power dissipation. Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS8474A-02 December 2013 2