RT8204AGQW Richtek

RT8204A Single Synchronous Buck with LDO Controller General Description Features zz z zz PWM Controller The RT8204A PWM controller provides the high efficiency, Ultra-High Efficiency excellent transient response, and high DC output accuracy Resistor Programmable Current Limit by Low Side needed for stepping down high voltage batteries to R Sense (Lossless Limit) or Sense Resistor DS(ON) generate low voltage CPU core, I/O, and chipset RAM (High Accuracy) supplies in notebook computers. Quick Load Step Response within 100ns The constant-on-time PWM control scheme handles wide 1% V Accuracy Over Line and Load OUT input/output voltage ratios with ease and provides 100ns Adjustable 0.75V to 3.3V Output Range instant-on response to load transients while maintaining 3V to 26V Battery Input Range a relatively constant switching frequency. Resistor Programmable Frequency The RT8204A achieves high efficiency at a reduced cost Over/Under Voltage Protection by eliminating the current sense resistor found in 2 Steps Current Limit During Soft-Start traditional current mode PWMs. Efficiency is further Drives Large Synchronous-Rectifier FETs enhanced by its ability to drive very large synchronous Power Good Indicator rectifier MOSFETs. The buck conversion allows this device zz z zz LDO Controller to directly step down high voltage batteries for the highest 1.5% Accuracy Over Line and Load possible efficiency. The RT8204A is intended for CPU core, Adjustabe Output Voltage down to 0.75V chipset, DRAM, or other low voltage supplies as low as Independent Enable and Power Good Indicator 0.75V. Drive N-MOSFETs within Rail to Rail Controller Voltage A built-in LDO controller can drive an external N-MOSFET MLCC and POSCAP Stable to provide a second output voltage from PWM output or zz z zz RoHS Compliant and 100% Lead (Pb)-Free other power source. The RT8204A can provide adjustable voltage down to 0.75V and maximum output voltage is depended on the selected MOSFET. The internal 0.75V Ordering Information reference voltage with 1.5% accuracy provides tight RT8204A regulation for the output voltage. The independent enable Package Type control, open drain power good indicator, under-voltage QW : WQFN-16L 3x3 (W-Type) protection and soft start make RT8204A to power the Lead Plating System system friendly. The RT8204A is available in WQFN-16L P : Pb Free 3x3 package. G : Green (Halogen Free and Pb Free) Note : Applications Richtek products are : z Notebook Computers RoHS compliant and compatible with the current require- z CPU Core Supply ments of IPC/JEDEC J-STD-020. z Chipset/RAM Supply as Low as 0.75V Suitable for use in SnPb or Pb-free soldering processes. Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. DS8204A-05 April 2011 www.richtek.com 1D1 V IN BAT254 3V to 26V R4 1M C4 R5 10F RT8204A 2.2 16 13 C3 V TON BOOT OUT1 0.1F 1.2V 9 Q1 VDDP 6 0 R 12 AO4704 UGATE L1 2.4 H 11 2 PHASE 8 C9 LG TE R8 A 220F Q2 k R7 10 1 0 AO4704 OC R9 C5 4 C6 12k 3 15 FB EN/ EM D CCM/DEM R10 14 C13 LDO Enable 20k 0.1F 5 LDO PGOOD 1 VOUT VDDP C12 Q3 7 AO4404 R11 V OU 2 T Exposed Pad(17) 1.05V C7 C8 R12 C11 C10 33nF 12k 220F 10F 6 R13 30k RT8204A Pin Configurations (TOP VIEW) 16 15 14 13 UGATE VOUT 1 12 11 VDD 2 PHASE GND FB 3 10 OC 17 4 VDDP PGOOD 9 5 6 7 8 WQFN-16L 3x3 Typical Application Circuit LEN LPGOOD LDRV LFB www.richtek.com DS8204A-05 April 2011 2 DP VD 5V C1 7F 4. R2 R1 00k 1 10 VDD C2 1F PGOOD PGOOD R3 100k GND LPGOOD TON EN/DEM LFB LDRV LEN LGATE BOOT