RT2853A/B TM 3A, 18V, 650kHz, ACOT Synchronous Step-Down Converter General Description Features zz z zz Fast Transient Response The RT2853A/B are high-performance 650kHz 3A step- zz z zz Steady 650kHz Switching Frequency down regulators with internal power switches and zz z zz Enhanced Efficiency at Light Load (RT2853A) synchronous rectifiers. They feature quick transient TM zz z zz Advanced Constant On-Time (ACOT ) Control response using their Advanced Constant On-Time TM zz z zz Optimized for Ceramic Output Capacitors (ACOT ) control architecture that provides stable zz z zz 4.5V to 18V Input Voltage Range operation with small ceramic output capacitors and without zz z zz Internal 110m Switch and 30m Synchronous complicated external compensation, among other benefits. Rectifier The input voltage range is from 4.5V to 18V and the output zz z zz 0.765V to 7V Adjustable Output Voltage is adjustable from 0.765V to 7V. zz z zz Externally-adjustable, Pre-biased Compatible Soft- TM The proprietary ACOT control improves upon other fast- Start response constant on-time architectures, achieving nearly zz z zz Cycle-by-Cycle Current Limit constant switching frequency over line, load, and output zz z zz Optional Output Discharge Function voltage ranges. Since there is no internal clock, response zz z zz Output Over- and Under-voltage Shut-down to transients is nearly instantaneous and inductor current Latched (RT2853ALGQW/RT2853BLGQW Only) can ramp quickly to maintain output regulation without With Hiccup Mode (RT2853AHGQW/ large bulk output capacitance. The RT2853A/B are stable RT2853BHGQW Only) with and optimized for ceramic output capacitors. With internal 110m switches and 30m synchronous Applications rectifiers, the RT2853A/B display excellent efficiency and z Industrial and Commercial Low Power Systems good behavior across a range of applications, especially z Computer Peripherals for low output voltages and low duty cycles. Cycle-by- z LCD Monitors and TVs cycle current limit, input under-voltage lock-out, externally- z Point of Load Regulation for High-Performance DSPs, adjustable soft-start, output under- and over-voltage FPGAs, and ASICs protection, and thermal shutdown provide safe and smooth operation in all operating conditions. Fast-Transient Response The RT2853A and RT2853B are each available in WQFN-16L 3x3 package, with exposed thermal pads. RT2853B V OUT (50mV/Div) Simplified Application Circuit RT2853A/B V VIN V IN SW OUT VCC BOOT Power Good VS PGOOD VREG5 FB Input Signal EN I OUT SS VREG5 GND PGND (1A/Div) VIN = 12V, VOUT = 1.05V, IOUT = 0 to 3A Time (100s/Div) Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS2853A/B-01 July 2013 www.richtek.com 1RT2853A/B Ordering Information Pin Configurations RT2853A/B (TOP VIEW) Package Type QW : WQFN-16L 3x3 (W-Type) 16 15 14 13 Lead Plating System 1 12 FB BOOT G : Green (Halogen Free and Pb Free) 2 11 VREG5 SW GND SS 3 10 SW 17 H : Hiccup Mode OVP & UVP GND 4 9 SW L : Latched OVP & UVP 5 6 7 8 A : Enhanced Light Load Efficiency B : Continuous Switching Mode Note : Richtek products are : WQFN-16L 3x3 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 RT2853AHGQW RT2853BHGQW 2K= : Product Code 2H= : Product Code YMDNN : Date Code YMDNN : Date Code 2K=YM 2H=YM DNN DNN RT2853ALGQW RT2853BLGQW 2J= : Product Code 2G= : Product Code YMDNN : Date Code YMDNN : Date Code 2J=YM 2G=YM DNN DNN Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS2853A/B-01 July 2013 2 PGOOD VS EN VCC PGND VIN PGND VIN