RT7275GQW

® RT7275/76 3A, 18V, 700kHz ACOTTM Synchronous Step-Down Converter General Description Features The RT7275/76 are high-performance 700kHz 3A stepdown regulators with internal power switches and synchronous rectifiers. They feature quick transient response using their Advanced Constant On-Time (ACOT TM) control architecture that provides stable z Fast Transient Response z operation with small ceramic output capacitors and without complicated external compensation, among other benefits. The input voltage range is from 4.5V to 18V and the output is adjustable from 0.765V to 8V. z The proprietary ACOTTM control improves upon other fastresponse constant on-time architectures, achieving nearly constant switching frequency over line, load, and output voltage ranges. Since there is no internal clock, response to transients is nearly instantaneous and inductor current can ramp quickly to maintain output regulation without large bulk output capacitance. The RT7275/76 are stable with and optimized for ceramic output capacitors. z Steady 700kHz Switching Frequency ` At all Load Currents (RT7275) ` Discontinuous Operating Mode at Light Load (RT7276) 3A Output Current Advanced Constant On-Time (ACOTTM) Control Optimized for Ceramic Output Capacitors 4.5V to 18V Input Voltage Range Internal 90mΩ Ω Switch and 60mΩ Ω Synchronous Rectifier 0.765V to 8V Adjustable Output Voltage z z z z z z z z With internal 90mΩ switches and 60mΩ synchronous rectifiers, the RT7275/76 display excellent efficiency and good behavior across a range of applications, especially for low output voltages and low duty cycles. Cycle-bycycle current limit, input under-voltage lock-out, externally-adjustable soft-start, output under- and overvoltage protection, and thermal shutdown provide safe and smooth operation in all operating conditions. The RT7275 and RT7276 are each available in WDFN-10L 3x3 and PTSSOP-14 packages, with exposed thermal pads. Externally-adjustable, Pre-biased Compatible SoftStart Cycle-by-Cycle Current Limit Optional Output Discharge Function (PTSSOP-14 Only) Output Over- and Under-voltage Shut-down Applications z z z z z z Industrial and Commercial Low Power Systems Computer Peripherals LCD Monitors and TVs Green Electronics/Appliances Point of Load Regulation for High-Performance DSPs, FPGAs, and ASICs Not Recommended for Sink/Source Applications Fast-Transient Response RT7275 Simplified Application Circuit VIN Input Signal Power Good RT7275/76 VIN SW VINR EN VOUT (20mV/Div) VOUT BOOT FB PGOOD VOUT PVCC SS PGND GND IOUT (2A/Div) VIN = 12V, VOUT = 1.05V, IOUT = 0 to 3A Time (100μs/Div) Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS7275/76-00 January 2013 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT7275/76 Ordering Information Pin Configurations (TOP VIEW) RT7275/76 Operating Mode 75 : Continuous Switching Mode 76 : Discontinuous Operating Mode at Light Load 3 4 12 PGND 5 11 10 6 9 15 7 EN FB PVCC SS PGOOD Richtek products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` 13 8 TSSOP-14 (Exposed Pad) Note : ` VINR VIN BOOT SW SW PGND PGND 14 2 1 2 3 4 5 PGND Lead Plating System G : Green (Halogen Free and Pb Free) VOUT FB PVCC SS GND PGOOD EN 11 10 9 8 7 9 Package Type CP : TSSOP-14 (Exposed Pad) QW : WDFN-10L 3x3 (W-Type) VIN VIN BOOT SW SW WDFN-10L 3x3 Suitable for use in SnPb or Pb-free soldering processes. Marking Information RT7276GCP RT7275GCP RT7275GCP : Product Number RT7275 GCPYMDNN YMDNN : Date Code RT7276GCP : Product Number RT7276 GCPYMDNN RT7276GQW RT7275GQW 2C= : Product Code 4C= : Product Code 4C=YM DNN YMDNN : Date Code Copyright © 2013 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 YMDNN : Date Code 2C=YM DNN YMDNN : Date Code is a registered trademark of Richtek Technology Corporation. DS7275/76-00 January 2013 RT7275/76 Absolute Maximum Ratings z z z z z z z z z z z z z (Note 1) Supply Input Voltage, VIN, VINR (TSSOP-14 (Exposed Pad)) ----------------------------------------- −0.3V to 21V Switch Node, SW ------------------------------------------------------------------------------------------------- −0.8V to (VVIN + 0.3V) Switch Node, SW (