RT5712E 2A, 1MHz, 6V CMCOT Synchronous Step-Down Converter General Description Features Efficiency Up to 95% The RT5712E is a high efficiency synchronous R 100m HS / 70m LS DSON step-down DC/DC converter. Its input voltage range is V Range 2.7V to 6V IN from 2.7V to 6V and provides an adjustable regulated V 0.6V with 1.5% Accuracy REF output voltage from 0.6V to 3.4V while delivering up to CMCOT Control Loop Design for Best 2A of output current. Transient Response, Robust Loop Stability with The internal synchronous low on-resistance power Low-ESR (MLCC) C OUT switches increase efficiency and eliminate the need for Fixed Soft-Start 1.2ms an external Schottky diode. The Current Mode Cycle-by-Cycle Over Current Protection Constant-On-time (CMCOT) operation with internal Input Under Voltage Lockout compensation allows the transient response to be Output Under Voltage Protection (UVP Hiccup) optimized over a wide range of loads and output Thermal Shutdown Protection capacitors. Power Saving at Light Load Applications Marking Information STB, Cable Modem, & xDSL Platforms RT5712EHGQW LCD TV Power Supply & Metering Platforms 3U : Product Code W : Date Code General Purpose Point of Load (POL) 3UW Ordering Information RT5712E RT5712ELGQW 3T : Product Code Package Type W : Date Code QW : WDFN-6L 2x2 (W-Type) 3TW Lead Plating System G : Green (Halogen Free and Pb Free) UVP Option Pin Configurations H : Hiccup L : Latch-Off (TOP VIEW) Note : 1 6 PGOOD FB Richtek products are : 2 5 EN GND RoHS compliant and compatible with the current 3 7 4 VIN LX requirements of IPC/JEDEC J-STD-020. WDFN-6L 2x2 Suitable for use in SnPb or Pb-free soldering processes. Simplified Application Circuit L V LX VIN V IN OUT C IN RT5712E R1 EN FB C OUT PGOOD GND R2 Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5712E-01 December 2015 www.richtek.com 1 GNDRT5712E Functional Pin Description Pin No. Pin Name Pin Function Power Good Indicator. The output of this pin is an open-drain with external 1 PGOOD pull-up resistor. PGOOD is pulled up when the FB voltage is within 90%, otherwise it is LOW. 2 EN Enable Control Input. 3 VIN Supply Voltage Input. The RT5712E operates from a 2.7V to 6V input. 4 LX Switch Node. Ground. The exposed pad must be soldered to a large PCB and connected to 5, 7 (Exposed Pad) GND GND for maximum thermal dissipation. 6 FB Feedback. Function Block Diagram EN VIN UVLO Shut Down Control LX Ton OTP VIN Error Comparator Logic Amplifier - FB + Control Driver LX V + REF - R C Current C COMP Limit GND Detector + - Current LX Sense PGOOD Operation The RT5712E is a synchronous low voltage step-down UV Comparator converter that can support the input voltage range from If the feedback voltage (V ) is lower than threshold FB 2.7V to 6V and the output current can be up to 2A. The voltage 0.2V, the UV comparator s output will go high RT5712E uses a constant on-time, current mode and the switch controller will turn off the high side architecture. In normal operation, the high side MOSFET. The output under voltage protection is P-MOSFET is turned on when the switch controller is designed to operate in Hiccup and Latch-off mode. set by the comparator and is turned off when the Ton PGOOD Comparator comparator resets the switch controller. When the feedback voltage (V ) is higher than FB Low side MOSFET peak current is measured by threshold voltage 0.54V, the PGOOD open drain output internal RSENSE. The error amplifier EA adjusts will be high impedance. The internal PGOOD MOSFET COMP voltage by comparing the feedback signal (V ) FB is typical 100. The PGOOD signal delay time from EN from the output voltage with the internal 0.6V reference. is about 2ms. When the load current increases, it causes a drop in the feedback voltage relative to the reference, then the COMP voltage rises to allow higher inductor current to match the load current. Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5712E-01 December 2015 2