RT5712B 2A, 1MHz, 6V CMCOT Synchronous Step-Down Converter General Description Features Efficiency Up to 95% The RT5712B 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. Marking Information Applications RT5712BHGQW STB, Cable Modem, & xDSL Platforms 3K : Product Code W : Date Code LCD TV Power Supply & Metering Platforms 3KW General Purpose Point of Load (POL) Ordering Information RT5712BLGQW 3J : Product Code RT5712B W : Date Code Package Type 3JW QW : WDFN-6L 2x2 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) Pin Configurations UVP Option H : Hiccup (TOP VIEW) L : Latch-Off 1 6 IC FB Note : 2 5 EN GND Richtek products are : VIN 3 7 4 LX RoHS compliant and compatible with the current 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 RT5712B R1 EN FB C OUT GND R2 Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5712B-01 December 2015 www.richtek.com 1 GNDRT5712B Functional Pin Description Pin No. Pin Name Pin Function 1 IC No Internal Connection. 2 EN Enable Control Input. 3 VIN Supply Voltage Input. The RT5712B 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 Operation The RT5712B 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 RT5712B 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 Enable Comparator comparator resets the switch controller. A logic-high enables the converter a logic-low forces Low side MOSFET peak current is measured by the IC into shutdown mode. internal RSENSE. The error amplifier EA adjusts COMP voltage by comparing the feedback signal (V ) FB Soft-Start (SS) from the output voltage with the internal 0.6V reference. An internal current source charges an internal capacitor When the load current increases, it causes a drop in to build the soft-start ramp voltage. The V voltage will FB the feedback voltage relative to the reference, then the track the internal ramp voltage during soft-start interval. COMP voltage rises to allow higher inductor current to The typical soft-start time is 1.2ms. match the load current. Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5712B-01 December 2015 2