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5-Bit Programmable 2-, 3-, 4-Phase

Synchronous Buck Controller

*Patent pending

FEATURES

Selectable 2-, 3- or 4-Phase Operation at up to

1 MHz per Phase

Differential Sensing Error

±1% over Temperature

Logic-Level PWM Outputs for Interface to

External High Power Drivers

Active Current Balancing between All Output Phases

Built-in Power Good Blanking Supports On-the-Fly

VID Code Changes

5-Bit Digitally Programmable 0.8 V to 1.55 V Output

Short-Circuit Protection with Programmable

Latch-Off Delay

Overvoltage Protection Crowbar Logic Output

APPLICATIONS

Desktop PC Power Supplies

Next-Generation AMD Processors

VRM Modules

FUNCTIONAL BLOCK DIAGRAM

VCC

PRECISION

REFERENCE

SOFT

START

UVLO

SHUTDOWN

AND BIAS

OSCILLATOR

–

+

GND

ADP3166

EN

DELAY

ILIMIT

PWRGD

RT

RAMPADJ

PWM2

FB

PWM3

PWM4

SW1

CSSUM

CSCOMP

SW2

SW3

SW4

CSREF

PWM1

VID4

VID3

VID2

VID1

VID0

FBRTN

COMP

VID

DAC

+

–

DAC + 300mV

+

–

DAC – 300mV

+

–

+

–

CSREF

CSREF

2.1V

EN

CURRENT

LIMIT

CIRCUIT

CROWBAR

CURRENT

LIMIT

+

–

CMP

+

–

CMP

+

–

CMP

–

+

+

–

CMP

CURRENT

BALANCING

CIRCUIT

2-, 3-, 4-PHASE

DRIVER LOGIC

EN

SET

RESET

RESET

RESET

RESET

CROWBAR

28

11

6

15

12

9

7

1

2

3

4

5

8

18

16

17

20

21

22

23

24

25

26

27

13

14

10

DELAY

19

GENERAL DESCRIPTION

The ADP3166 is a highly efficient, multiphase, synchronous

buck switching regulator controller optimized for converting a

12 V main supply into the core supply voltage required by high

performance AMD processors. It uses an internal 5-bit DAC to

read a voltage identification (VID) code directly from the pro-

cessor, which is used to set the output voltage between 0.8 V

and 1.55 V. The ADP3166 also uses a multimode PWM

architecture to drive the logic-level outputs at a programmable

switching frequency that can be optimized for VRM size and

efficiency. The phase relationship of the output signals can be

programmed to provide 2-, 3-, or 4-phase operation, allowing

for the construction of up to four complementary buck switch-

ing stages.

The ADP3166 includes programmable no-load offset and slope

functions to adjust the output voltage as a function of the load

current so that it is always optimally positioned for a system

transient. The ADP3166 also provides accurate and reliable

short-circuit protection, adjustable current limiting, and a delayed

power good output that accommodates on-the-fly output volt-

age changes requested by the CPU.

ADP3166 is specified over the commercial temperature range of

0

°C to 85°C and is available in a 28-lead TSSOP package.