L6756 2/3/4 phase buck controller for VR10, VR11.1 and AM2 processor applications Data Brief Features ■ LTB technology® enhances load transient response ■ 2 to 4 scalable phase operation ■ Dual-edge asynchronous architecture ■ PSI# input with programmable strategy ■ IMON output ■ Flexible driver support ■ 7/8 bit programmable output - VR10/11.x DAC ■ 6 bit programmable output - AMD AM2 DAC ■ 0.5 % output voltage accuracy ■ Full-differential current sense across DCR ■ Integrated remote sense buffer ■ Feedback disconnection protection ■ Adjustable oscillator from 100 kHz to 1 MHz ■ LSLess startup to manage pre-biased ouptut ■ Programmable Soft-start ■ Threshold sensitive enable Pin for VTT Sensing ■ VFQFPN40 7x7 mm package VFQFPN40 Description L6756 is a two-to-four phase controller designed to power Intel’s most demanding Processors and, most in general, low-voltage, high-current power supplies. The device features LTB technology® to provide the fastest response to load transients thus minimizing the output filter composition. L6756 embeds selectable DAC: Output Voltage is programmable up to 1.6000 V (Intel VR10 and VR11.x DACs) or up to 1.550 V (AMD 6bit DAC) managing DVID transitions with ±0.5 % output voltage accuracy over line, load and temperature variations. The device assures fast protection against load over current and under / over voltage. Feedback disconnection prevents from damaging the load in case of misconnections in the system board. Applications ■ High-current VRM / VRD for desktop / server / workstation CPUs ■ Graphic cards ■ Low-voltage, high-current power supplies ■ High-density DC / DC converters Table 1. Low-Side-Less start-up allows soft-start over prebiased output avoiding dangerous current return through the main inductors as well as negative spike at the load side. L6756 is available in VFQFPN40 7x7 mm package. Device summary Order code Package Packing L6756 VFQFPN40 Tube L6756TR VFQFPN40 Tape & Reel February 2008 Rev 1 For further information contact your local STMicroelectronics sales office. 1/3 www.st.com 3 Revision history 1 L6756 Revision history Table 2. 2/3 Document revision history Date Revision 15-Feb-2008 1 Changes Initial release. L6756 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. 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