RT8481AGE Richtek

RT8481A SPS Secondary-Side CC/CV Controller General Description Features Secondary-Side Constant Voltage (CV) and Constant The RT8481A is a secondary-side CC/CV controller for Current (CC) Control SPS applications. It integrates a Constant Current (CC) 4.75V to 50V Operation Voltage Range regulating amplifier, a Constant Voltage (CV) regulating 1% Output Voltage Accuracy at Full Temperature amplifier, and 2 precision reference voltages. Range The CC regulating amplifier is featured with an extended 0.6mA Quiescent Current input common mode voltage below GND level to insure Smooth Transition Between CC and CV Control the performance of low-side current sense, and a very low Loops input offset voltage to guarantee the sensing accuracy. A 5V Negative Voltage Tolerance at CP pin 60mV reference voltage is internally connected between the inverting input of the CC regulating amplifier and the Applications CP pin. The non-inverting input is the CN pin, at which the Battery Chargers voltage will be regulated 60mV higher than that at the CP AC/DC Adaptors pin. The inverting input pin CP is equiped with 5V anti- LED Drivers reverse immunity. The CV regulating amplifier with low input offset voltage is biased with a 2.5V reference voltage at the inverting input. The non-inverting input is the FB pin, at which the voltage will be regulated with 2.5V from GND. The CC and CV amplifiers share an open-collector output pin to minimize application circuit. The RT8481A is available in the SOT-23-6 package. Simplified Application Circuit V OUT Opto VCC R1 C VC1 R VC1 RT8481A OUT FB C IC1 R2 R IC1 CP CN GND R IC2 R S GND Copyright 2016 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS8481A-00 January 2016 www.richtek.com 1RT8481A Ordering Information Pin Configurations RT8481A (TOP VIEW) Package Type VCC OUT CP E : SOT-23-6 6 5 4 Lead Plating System G : Green (Halogen Free and Pb Free) 23 Note : CN FB GND Richtek products are : SOT-23-6 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. Marking Information 3Y= : Product Code 3Y=DNN DNN : Date Code Functional Pin Description Pin No. Pin Name Pin Function Non-inverting Input of the CC Regulating Amp. It has 60mV offset from the CP pin. The 1 CN CN pin should be connected to the current-in node of the current sensing resistor, Rs. 2 GND Ground. Non-inverting Input of the CV Regulating Amp. The pin should be connected to the 3 FB mid-point of a resistor divider from Secondary Side VOUT (usually the VCC) to GND. Inverting Input of the CC Regulating Amp with 60mV offset from CN pin. The CP pin 4 CP should be connected to the current-out node of the current sensing resistor. Common Open-collector Output of CC and CV Regulating Amps. The pin sinks a 5 OUT regulated current and driver the opto-coupler to transmit the error signal to primary-side. Supply Voltage Input. A 0.1F bypass capacitor should be connected between VCC and 6 VCC GND. Copyright 2016 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS8481A-00 January 2016 2