L6756DTR STMicroelectronics

L6756D 2/3/4 phase buck controller for VR10, VR11 and VR11.1 processor applications Features LTB Technology enhances load transient response 2 to 4 scalable phase operation Dual-edge asynchronous architecture PSI input with programmable strategy VFQFPN40 6x6 mm Imon output Flexible driver support Description 7/8 bit programmable output - VR10/11.1 DAC L6756D is a two-to-four phase controller designed 0.5% output voltage accuracy to power Intels most demanding processors and, Full-differential current sense across DCR most in general, low-voltage, high-current power Integrated remote sense buffer supplies. The device features LTB Technology to provide the fastest response to load transients Feedback disconnection protection thus minimizing the output Adjustable oscillator from 100 kHz to 1 MHz filter composition. LSLess startup to manage pre-biased output L6756D embeds selectable DAC: output voltage Programmable soft-start is programmable up to 1.6000 V (Intel VR10 and Threshold sensitive enable pin for VTT VR11.x DACs) managing DVID transitions with Sensing 0.5% output voltage accuracy over line, load and VFQFPN40 6x6 mm package temperature variations. The device assures fast protection against load over current and under / over voltage. Feedback disconnection prevents from damaging the load in Applications case of misconnections in the system board. High-current VRM / VRD for desktop / server / Low-side-less start-up allows soft-start over pre- workstation CPUs biased output avoiding dangerous current return Graphic cards through the main inductors as well as negative spike at the load side. Low-voltage, high-current power supplies High-density DC / DC converters L6756D is available in VFQFPN 6x6 mm package Table 1. Device summary Order code Package Packing L6756D VFQFPN40 Tube L6756DTR VFQFPN40 Tape and reel October 2008 Rev 1 1/36 www.st.com 1Contents L6756D Contents 1 Typical application circuit and block diagram 4 1.1 Application circuit 4 1.2 Block diagram . 7 2 Pins description and connection diagrams 8 2.1 Pin descriptions . 8 2.2 Thermal data 11 3 Electrical specifications . 12 3.1 Absolute maximum ratings 12 3.2 Electrical characteristics 12 4 Device description and operation . 19 5 Output voltage positioning . 20 5.1 Phase programming . 20 5.2 Current reading and current sharing loop 21 5.3 Output voltage load-line definition 22 5.4 Output voltage offset 22 5.5 Dynamic VID transitions 23 5.6 Soft-start 24 5.6.1 LSLESS start-up 25 6 Output voltage monitoring and protections . 26 6.1 Overvoltage . 26 6.2 Feedback disconnection 26 6.3 VR RDY 27 6.4 Over current . 27 7 Low power-state management and PSI 28 8 Main oscillator . 29 2/36