RT8101AGSP Richtek

RT8101/A 12V Synchronous Buck PWM DC/DC Controller General Description Features zz z zz Single 12V Bias Supply The RT8101/A are DC/DC synchronous buck PWM zz z zz Drives All Low Cost N-MOSFETs controllers with embedded driver support up to 12V + 12V zz z zz High-Gain Voltage Model PWM Control boot-strapped voltage for high efficiency power driving. The zz z zz 300kHz/600kHz Fixed Frequency Oscillator parts are with full functions of voltage regulation, power zz z zz Fast Transient Response : monitoring and protection into a single small footprint High-Speed GM Amplifier packages SOP-8 and SOP-8 (Exposed Pad). Full 0 to 100% Duty Ratio The RT8101/A apply a high-gain voltage mode PWM control External Compensation in the Control Loop for simple application design. An internal 0.8V reference zz z zz Internal Soft-Start allows the output voltage to be precisely regulated to low zz z zz Adaptive Non-Overlapping Gate Driver voltage requirement. The parts are proposed with two type zz z zz Over Current Fault Monitor on MOSFET, No including RT8101 and RT8101A with fixed operating Current Sense Resistor Required zz z zz RoHS Compliant and 100% Lead (Pb)-Free frequency of 300kHz and 600kHz respectively. Based on the features that RT8101/A offered, the parts provide an Applications optimum solution between efficiency, total B.O.M. count, and cost. z Graphic Card z Motherboard, Desktop Servers z IA Equipments Ordering Information z Telecomm Equipments RT8101/A z High Power DC/DC Regulators Package Type S : SOP-8 SP : SOP-8 (Exposed Pad-Option 2) Pin Configurations Lead Plating System (TOP VIEW) P : Pb Free G : Green (Halogen Free and Pb Free) BOOT PHASE 8 600kHz UGATE 2 COMP 7 300kHz GND 3 6 FB LGATE 4 5 VCC Note : Richtek products are : SOP-8 RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. 8 BOOT PHASE 2 7 Suitable for use in SnPb or Pb-free soldering processes. UGATE COMP GND 3 GND 6 FB 9 LGATE 4 5 VCC SOP-8 (Exposed Pad) DS8101/A-06 April 2011 www.richtek.com 1V (+3.3V/+5V/+12V) IN 12V L OUT V OUT C OUT RT8101/A Typical Application Circuit R BOOT C IN RT8101/A R UGATE 1 2 BOOT UGATE Q1 5 8 VCC PHASE 6 4 FB LGATE Q2 R 7 3 COMP GND C PSC Functional Pin Description BOOT (Pin 1) FB (Pin 6) Bootstrap supply for the upper gate driver. Connect the Buck converter feedback voltage. This pin is the inverting bootstrap capacitor between BOOT pin and the PHASE input of the error amplifier. FB senses the switcher output pin. The bootstrap capacitor provides the charge to turn through an external resistor divider network. on the upper MOSFET. COMP (Pin 7) UGATE (Pin 2) Buck converter external compensation. This pin is used Upper gate driver output. Connect to gate of the high- to compensate the control loop of the buck converter. side power N-Channel MOSFET. This pin is monitored by PHASE (Pin 8) the adaptive shoot-through protection circuitry to Connect this pin to the source of the upper MOSFET and determine when the upper MOSFET is turned off. the drain of the lower MOSFET. This pin is monitored by GND (Pin 3) the adaptive shoot-through protection circuitry to Signal ground for the IC. determine when the upper MOSFET is turned off. LGATE (Pin 4) Exposed Pad (9) Lower gate driver output. Connect to the gate of the low- The exposed pad must be soldered to a large PCB and side power N-Channel MOSFET. This pin is monitored by connected to GND for maximum power dissipation. the adaptive shoot-through protection circuitry to determine when the lower MOSFET is turned off. VCC (Pin 5) Connect this pin to a well-decoupled 12V bias supply. It is also the positive supply for the lower gate driver, LGATE. DS8101/A-06 April 2011 www.richtek.com 2