buck controller. L6756D Datasheet

L6756D controller. Datasheet pdf. Equivalent

Part L6756D
Description 2/3/4 phase buck controller
Feature L6756D 2/3/4 phase buck controller for VR10, VR11 and VR11.1 processor applications www.DataSheet4U..
Manufacture STMicroelectronics
Datasheet
Download L6756D Datasheet



L6756D
www.DataSheet4U.net
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
Imon output
Flexible driver support
7/8 bit programmable output - VR10/11.1 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 output
Programmable soft-start
Threshold sensitive enable pin for VTT
Sensing
VFQFPN40 6x6 mm package
Applications
High-current VRM / VRD for desktop / server /
workstation CPUs
Graphic cards
Low-voltage, high-current power supplies
High-density DC / DC converters
VFQFPN40 6x6 mm
Description
L6756D 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.
L6756D embeds selectable DAC: output voltage
is programmable up to 1.6000 V (Intel VR10 and
VR11.x DACs) 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.
Low-side-less start-up allows soft-start over pre-
biased output avoiding dangerous current return
through the main inductors as well as negative
spike at the load side.
L6756D is available in VFQFPN 6x6 mm package
Table 1.
Device summary
Order code
L6756D
L6756DTR
Package
VFQFPN40
VFQFPN40
Packing
Tube
Tape and reel
October 2008
Rev 1
1/36
www.st.com
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L6756D
Contents
Contents
L6756D
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
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