6-Bit Programmable 2- to 4-Phase

Synchronous Buck Controller

ADP3196

Rev. 0

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FEATURES

Selectable 2-, 3-, or 4-phase operation at up to 1 MHz

per phase

±10 mV worst-case differential sensing error over

temperature

Logic-level PWM outputs for interface to external

high power drivers

Enhanced PWM flex mode for excellent load transient

performance

Active current balancing between all output phases

Built-in power-good/crowbar blanking supports on-the-fly

VID code changes

Digitally programmable 0.3750 V to 1.55 V output

Programmable short-circuit protection with programmable

latch-off delay

APPLICATIONS

Desktop PC power supplies for next generation

AMD processors

VRM modules

GENERAL DESCRIPTION

buck switching regulator controller optimized for converting a

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

performance Advanced Micro Devices, Inc. (AMD) processors.

It uses an internal 6-bit DAC to read a voltage identification

(VID) code directly from the processor, which is used to set the

output voltage between 0.3750 V and 1.55 V.

This device uses a multimode PWM architecture to drive the

logic-level outputs at a programmable switching frequency that

can be optimized for VR 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 switching stages.

The ADP3196 supports a programmable slope function to

adjust the output voltage as a function of the load current so

that it is always optimally positioned for a system transient. This

can be disabled by connecting Pin LLSET to Pin CSREF.

FUNCTIONAL BLOCK DIAGRAM

VCC

PRECISION

REFERENCE

DELAY

–

+

GND

ADP3196

EN

DELAY

ILIMIT

PWRGD

RAMPADJ

RT

PWM2

PWM3

PWM4

SW3

SW2

SW1

CSREF

CSCOMP

SW4

CSSUM

FB

PWM1

VID5 VID4 VID3

VID2

VID0

VID1

COMP

FBRTN

VID DAC

–

+

800mV

–

+

CSREF

1.8V

CURRENT

MEASUREMENT

AND LIMIT

CROWBAR

CURRENT

LIMIT

+

–

CMP

+

–

CMP

+

–

CMP

+

–

+

–

CMP

CURRENT

BALANCING

CIRCUIT

2-/3-/4-PHASE

DRIVER LOGIC

EN

SET

RESET

RESET

RESET

RESET

OD

SS

–

+

IREF

THERMAL

THROTTLING

CONTROL

TTSENSE

VRMHOT

VRM_OFF

LLSET

UVLO

SHUTDOWN

SHUNT

REGULATOR

IMON

–

+

DAC – 250mV

OSCILLATOR

SOFT START

CONTROL

13

12

31

18

1

2

10

9

11

8

7

5

20

3

39

35

34

38

36

37

6

23

16

15

29

28

27

19

17

4

24

22

25

30

14

21

Figure 1. Functional Block Diagram

The ADP3196 also provides accurate and reliable short-circuit

protection, adjustable current limiting, and a delayed power-

good output that accommodates on-the-fly output voltage

changes requested by the CPU. The ADP3196 has a built-in

shunt regulator that allows the part to be connected to the 12 V

system supply through a series resistor.

The ADP3196 is specified over the extended commercial

temperature range of 0°C to +85°C and is available in a

40-lead LFCSP.