LTC1706-61

170661f

5-Bit VID-Controlled High Current Application (Simplified Block Diagram)

5-Bit VID Voltage

Programmer for AMD

Opteron CPUs

Programs Regulator Output Voltage Range from
0.8V to 1.55V in 25mV Steps

Programs a Wide Range of Linear Technology
DC/DC Converters with a 0.6V Reference

0.35% Accurate Output Voltage

Built-In 40k Pull-Up Resistors on VID Inputs

Available in MSOP-10 Package

The LTC

1706-61 is a precision, digitally programmed,

resistive ladder which adjusts the output of any 0.6V
referenced regulator. Depending on the state of the five
VID inputs, an output voltage between 0.8V and 1.55V is
programmed in 25mV increments.

The LTC1706-61 is designed specifically to program
an entire family of Linear Technology DC/DC converters
with on board 0.6V references.

The LTC1706-61 programs the following Linear
Technology DC/DC converter products: LTC1629-6,
LTC3714, LTC3731 and LTC3778. (Consult factory for
additional DC/DC converter products.)

AMD Opteron

Processor Power Supply

Workstations and Servers

Large Memory Array Supply

, LTC and LT are registered trademarks of Linear Technology Corporation.

1706-61 TA01

SENSE1

4.5V TO 22V

LTC1629-6

INTV

DIFFOUT

SGND

EAIN

OUT

TG1

SW1

BG1

PGND

OUT

0.8V TO 1.55V
UP TO 80A

VID0

VID1

VID2

VID3

VID4

LTC1706-61

GND

SENSE

FROM

SENSE2

SENSE3

LTC1629-6

SGND

EAIN

TG1

SW1

BG1

PGND

SENSE4

TG2

SW2

BG2

TG2

SW2

BG2

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

AMD Opteron is a trademark of Advanced Micro Devices, Inc.

LTC1706-61

170661f

Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.

Note 2: The LTC1706EMS-61 is guaranteed to meet performance
specifications from 0

C to 70

C. Specifications over the 40

C to 85

operating temperature range are assured by design, characterization and
correlation with statistical process controls.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Operating Supply Voltage Range

2.7

5.5

VCC

Supply Current

(Note 3)

0.1

FB-SENSE

Resistance Between SENSE and FB

OUT

Error %

Output Voltage Accuracy

0.35

+ 0.35

PULLUP

VID Input Pull-Up Resistance

DIODE

= 0.6V (Note 4)

VID

VID Input Voltage Threshold

(2.7V

5.5V)

0.4

(2.7V

5.5V)

1.6

VID-LEAK

VID Input Leakage Current

< VID < 7V (Note 4)

0.01

PULLUP

VID Pull-Up Voltage

= 3.3V

2.8

= 5V

4.5

LTC1706EMS-61

JMAX

= 110

= 120

C/ W

(Note 1)

ABSOLUTE

AXI

RATINGS

PACKAGE/ORDER I

FOR

ATIO

ELECTRICAL CHARACTERISTICS

Consult LTC Marketing for parts specified with wider operating temperature ranges.

The

denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25

2.7V

5.5V, VID0 = VID1 = VID2 = VID3 = VID4 = NC unless otherwise specified.

(Voltages Referred to GND Pin)
Input Supply Voltage (V

) .......................... 0.3V to 7V

VID Input Pins ............................................. 0.3V to 7V
SENSE Pin ................................................... 0.3V to 7V
FB Pin .......................................................... 0.3V to 7V
Operating Ambient Temperature Range
(Note 2) .................................................. 40

C to 85

Junction Temperature ........................................... 110

Storage Temperature Range ................. 65

C to 150

Lead Temperature (Soldering, 10 sec).................. 300

1
2
3
4
5

VID0
VID1
VID2
VID3

10
9
8
7
6

FB
GND
NC
VID4
SENSE

TOP VIEW

MS PACKAGE

10-LEAD PLASTIC MSOP

ORDER PART

NUMBER

PART MARKING

LTK9

Note 3: With all five VID inputs floating, the V

supply current is simply

the device leakage current. However, the V

supply current will rise and

be approximately equal to the number of grounded VID input pins times
(V

0.6V)/40k. (See the VID Input Characteristics section for more

details.)

Note 4: Each built-in pull-up resistor attached to the VID inputs also has a
series diode connected to V

to allow input voltages higher than the V

supply without damage or clamping. (See Operation section for further
details.)

LTC1706-61

170661f

TYPICAL PERFOR

CE CHARACTERISTICS

TEMPERATURE (

100

VID PULL-UP CURRENT (

1706-61 G01

140

120

100

= 5V

VID4 = 0V
VID0 = VID1 = VID2 = VID3 = OPEN

VID-PULLUP

vs Temperature

TEMPERATURE (

100

SUPPLY CURRENT (

1706-61 G02

2.0

1.5

1.0

0.5

= 2.7V

= 5V

ALL VID INPUTS OPEN

= 3.3V

Supply Current vs Temperature

Supply Current vs Supply Voltage

VID0 (Pin 1): LSB Programming Input. Low = GND,
High = V

or Float. Grounding VID0 adds 25mV

to the output sense voltage.

VID1 (Pin 2): 4th MSB Programming Input. Low = GND,
High = V

or Float. Grounding VID1 adds 50mV

to the output sense voltage.

VID2 (Pin 3): 3rd MSB Programming Input. Low = GND,
High = V

or Float. Grounding VID2 adds 100mV

to the output sense voltage.

VID3 (Pin 4): 2nd MSB Programming Input. Low = GND,
High = V

or Float. Grounding VID3 adds 200mV

to the output sense voltage.

(Pin 5): Power Supply Voltage. Range from 2.7V to

5.5V.

SENSE (Pin 6): Regulator Output Voltage. Connect
directly to regulator output sense node.

VID4 (Pin 7): MSB Programming Input. Low = GND, High
= V

or Float. Grounding VID4 adds 400mV to the output

sense voltage.

NC (Pin 8): No Connect.

GND (Pin 9): Ground. Connect to regulator signal ground.

FB (Pin 10): Feedback Input. Connect to the 0.6V feedback
pin of a compatible regulator.

CTIO

SENSE VOLTAGE (V)

0.775

VID

ACCURACY

)

1706-61 G04

0.35

0.25

0.15

0.05

0.15

0.25

0.35

0.975

1.175

1.375

1.575

= 5.5V

= 2.7V

TEMPERATURE (

VID

ACCURACY

)

1706-61 G05

100

0.35

0.25

0.15

0.05

0.15

0.25

0.35

= 5.5V

SENSE

= 1.15V

SENSE

= 0.8V

SENSE

= 1.55V

VID

VID Sense Accuracy

VID Sense Accuracy vs
Temperature

FB1

vs Temperature

SUPPLY VOLTAGE (V)

2.5

4.5

3.5

3.0

4.0

5.0

5.5

6.0

SUPPLY CURRENT (

1706-61 G03

1.0

0.5

ALL VID INPUTS OPEN
T

= 25

TEMPERATURE (

100

FB1

)

1706-61 G06

10.10

10.05

10.00

9.95

9.90

LTC1706-61

170661f

BLOCK DIAGRA

1706-61 BD

40k

VID3

40k

VID4

40k

VID2

40k

VID1

40k

VID0

FB2

FB1

SENSE

GND

SWITCH

CONTROL

LOGIC

OPERATIO

The LTC1706-61 is a precision resistive divider designed
specifically for use with an entire family of Linear
Technology Corporation DC/DC switching regulators with
0.6V internal reference and feedback voltage. The
LTC1706-61 produces an output voltage ranging from
0.8V to 1.55V in 25mV steps by closing the loop between
the output voltage sense and the feedback input of the
regulator with the appropriate resistive divider network.

NOMINAL (V)

ABSOLUTE MAX (V)

PIN

NAME

DESCRIPTION

MIN

TYP

MAX

MIN

MAX

VID0

LSB Programmable Input

0.3

VID1

4th MSB Programmable Input

0.3

VID2

3rd MSB Programmable Input

0.3

VID3

2nd MSB Programmable Input

0.3

Power Supply

2.7

5.5

0.3

SENSE

Regulator Output Voltage

0.8

1.55

0.3

VID4

1st MSB Programmable Input

0.3

GND

Ground

0.3

0.6V Feedback Input

0.6

1.5

0.3

The "top" feedback resistor, R

FB1

, connected between

SENSE and FB, is typically 10k and is not modified by the
state of the VID program inputs.

The "bottom" feedback resistor, R

FB2

, however, is modi-

fied by the five VID inputs and is precisely ratioed to R

FB1

CTIO

LTC1706-61

170661f

Table 1. VID Inputs and Corresponding Output Voltage

CODE

VID4

VID3

VID2

VID1

VID0

OUTPUT

00000

GND

1.550V

00001

GND

Float

1.525V

00010

GND

Float

GND

1.500V

00011

GND

Float

1.475V

00100

GND

Float

GND

1.450V

00101

GND

Float

GND

Float

1.425V

00110

GND

Float

GND

1.400V

00111

GND

Float

1.375V

01000

GND

Float

GND

1.350V

01001

GND

Float

GND

Float

1.325V

01010

GND

Float

GND

Float

GND

1.300V

01011

GND

Float

GND

Float

1.275V

01100

GND

Float

GND

1.250V

01101

GND

Float

GND

Float

1.225V

01110

GND

Float

GND

1.200V

01111

GND

Float

1.175V

10000

Float

GND

1.150V

10001

Float

GND

Float

1.125V

10010

Float

GND

Float

GND

1.100V

10011

Float

GND

Float

1.075V

10100

Float

GND

Float

GND

1.050V

10101

Float

GND

Float

GND

Float

1.025V

10110

Float

GND

Float

GND

1.000V

10111

Float

GND

Float

0.975V

11000

Float

GND

0.950V

11001

Float

GND

Float

0.925V

11010

Float

GND

Float

GND

0.900V

11011

Float

GND

Float

0.875V

11100

Float

GND

0.850V

11101

Float

GND

Float

0.825V

11110

Float

GND

0.800V

11111

Float

*0.775V

*Represents codes without a defined output (shutdown) voltage as
specified in AMD specifications. The LTC1706-61 interprets these codes
as a valid input and produces an output voltage as follows:
(11111) = 0.775V.

OPERATIO

When all five VID inputs are high or floating, such as when
no CPU is present in a system, a regulated 0.775V output
is generated at V

SENSE

Each VID

input pin is pulled up by a 40k resistor in series

with a diode connected to V

. Therefore, it should be

grounded (or driven low) to produce a digital low input. It
can either be floated or connected to V

to get a digital

high input. The series diode is included to prevent the
input from being damaged or clamped when it is driven
higher than V

Voltage Sensing and Feedback Pins

The FB pin is a high impedance node that requires mini-
mum layout distance to reduce extra loading and
unwanted stray pickup.

When used with the LTC1629-6, the LTC1706-61's FB,
SENSE, V

and GND pins should be connected, respec-

tively, with the EAIN, V

DIFFOUT

, INTV

and SGND pins of

the LTC1629-6. The result of this application is a precisely
controlled, variable output voltage supply to any low
voltage, high current system such as a powerful personal
computer, workstation or network server.

VID Input Characteristics

The VID inputs should be driven with a maximum V

0.4V and a minimum V

of 1.6V. However, the VID input

range is not limited to values less than V

. Because of the

internal diode between V

and the pull-up resistor, the

inputs can go higher than V

without being clamped to

or damaging the input.

This allows the LTC1706-61 to be fully logic compatible
and operational over a higher input voltage range (less
than the 7V absolute maximum rating).

When a VID input is grounded, there will be a higher
quiescent current flow from V

because of a resistor from

through a series diode to each one of the inputs. This

increase in quiescent current is calculated from:

= N(V

DIODE

)/R

PULLUP

N is the number of grounded VID inputs. V

DIODE

is typically

0.6V while R

PULLUP

has a typical pull-up resistance of

40k

VID Programming

A list of programmed inputs and their corresponding
output voltages is shown in Table 1. Programming is
accomplished by applying the proper voltage (or float
condition) on the five digital VID inputs.

LTC1706-61

170661f

1 2 3

5 6 7 8

LTC3719

PGOOD

TG1

SW1

BOOST1

BG1

EXTV

INTV

PGND

BG2

BOOST2

SW2

TG2

ATTENIN

BIAS

VID4

VID3

VID2

RUN/SS

SENSE1

EAIN

PLLFLTR

PLLIN

FCB

SGND

DIFFOUT

SENSE2

ATTENOUT

NO_CPU

VID0

VID1

1 2 3

5 6 7 8

1 2 3

5 6 7 8

1 2 3

5 6 7 8

Q1
Si7448DP

C2
0.47

C5
0.47

C7 1

1nF

CLK1

C10 220pF

0.1

RUN/SS

PWRGD

ENABLE

VID0

VID1

VID2

VID3

VID4

BAT54

C14 470pF

C17

1nF

Q9 (OPT)
2N7002

INTV

C11
2.2

C12
10

R12 10

D3
BAT54A

Q2
Si7448DP

Q4
Si7448DP

Q3
Si7448DP

D2
B320A

0.8

D4
B320A

C8
0.47

C13
0.47

C15

0.47

C18
0.1

0.002

0.8

C16
0.47

0.002

OUT1

IN1

12V

GND

CORE

GND

COREFB_H

COREFB_L

R9
50

R6 2.2k

INTV

C9 4.7nF

R23 48.7k

R24
107k

IN1

: SIX 10

F 16V CERAMIC CAPACITORS

OUT1

: TEN 22

F 6.3V CERAMIC CAPACITORS

L1, L2: SUMIDA CEP125-1R0MC-H

VID0
VID1
VID2
VID3
VID4

FROM

LTC1706-61

LOGIC

SENSE

COMPARATOR

CORE

OVP
THRESHOLD

OVP

TO SYSTEM

OVERVOLTAGE

PROTECTION

1706-61 TA03

2-Phase 12V Input, 0.8V to 1.55V/45A Max Power Supply with Adjustable Overvoltage Protection

TYPICAL APPLICATIO

In other words, each VID input has a typical pull-up current
of 68

A for a 3.3V system.

Besides the LTC1629-6, the LTC1706-61 also programs a
whole family of LTC DC/DC converters that have an onboard

0.6V reference. The LTC3714, LTC3778 and LTC3731 are
just a few of the high efficiency step-down switching
regulators that will work equally well with the LTC1706-61.

OPERATIO

LTC1706-61

170661f

PACKAGE DESCRIPTIO

MS Package

10-Lead Plastic MSOP

(Reference LTC DWG # 05-08-1661)

0.8V to 1.55V VID Programmable 15A Power Supply

RUN/SS

PGOOD

RNG

FCB

SGND

EXTV

BOOST

SENSE

PGND

DRV

INTV

LTC3778

22pF

1500pF

20k

100k

330k

VID0
VID1
VID2
VID3
VID4

GND

SENSE

FROM

LTC1706-61

X5R

0.01

0.1

0.22

12V

OUT

0.8V TO 1.55V
15A

4.7

X5R

6.3V

16V

X5R

IRF7811

B320A

0.68

6.3V
X5R

270

CMDSH-3

1706-61 TA02

1
2
3
4
7

TYPICAL APPLICATIO

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

MSOP (MS) 0802

0.53

0.01

(.021

.006)

SEATING

PLANE

0.18

(.007)

1.10

(.043)

MAX

0.17 0.27

(.007 .011)

TYP

0.13

0.076

(.005

.003)

0.86

(.034)

REF

0.50

(.0197)

BSC

1 2 3 4 5

4.90

0.15

(1.93

.006)

0.497

0.076

(.0196

.003)

REF

7 6

3.00

0.102

(.118

.004)

(NOTE 3)

3.00

0.102

(.118

.004)

NOTE 4

NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX

0.254

(.010)

TYP

DETAIL "A"

GAUGE PLANE

5.23

(.206)

MIN

3.2 3.45

(.126 .136)

0.889

0.127

(.035

.005)

RECOMMENDED SOLDER PAD LAYOUT

0.305

0.038

(.0120

.0015)

TYP

0.50

(.0197)

BSC

LTC1706-61

170661f

LT/TP 0603 1K · PRINTED IN USA

LINEAR TECHNOLOGY CORPORATION 2002

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900

FAX: (408) 434-0507

www.linear.com

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

LTC1629-6

PolyPhase

Synchronous Step-Down Controller

Up to 12-Phase Operation, Up to 200A Power Supply

LTC3714

Single Phase Synchronous Step-Down Controller with VID

0.6V

OUT

1.75V, I

OUT

25A

LTC3716

2-Phase Synchronous Step-Down Controller with VID

0.6V

OUT

1.75V, I

OUT

40A

LTC3719

AMD Opteron CPU Power Supply

0.8V

OUT

1.55V, I

OUT

40A

LTC3731

3-Phase, 60A Synchronous Step-Down Controller

Single IC 60A Solution with Onboard MOSFET Drivers,

5% Output

Current Matching for Optimum Thermal Performance and Reliability

LTC3733

3-Phase, 60A Synchronous Step-Down Controller for

On-Board VID and MOSFET Drivers, 0.8V

OUT

1.55V, I

OUT

60A

AMD Opteron Processors

LTC3778

Optional R

SENSE

Synchronous Step-Down Controller

36V, 0.6V

OUT

(0.9)V

, I

OUT

25A

PolyPhase is a registered trademark of Linear Technology Corporation.

TYPICAL APPLICATIO

1706-61 TA04

RUN/SS

SENSE1

EAIN

PLLFLTR

PLLIN

PHASMD

SGND

DIFFOUT

SENSE2

RUN/SS

SENSE1

EAIN

PLLFLTR

PLLIN

PHASMD

SGND

DIFFOUT

SENSE2

CLKOUT

TG1

SW1

BOOST1

BG1

EXTV

INTV

PGND

BG2

BOOST2

SW2

TG2

AMPMD

12V

OUT

0.8V TO
1.55V
70A

VID0

VID1

VID2

VID3

VID4

LTC1706-61

GND

M1 TO M12: FDS7760A
L1 TO L4: 1

H SUMIDA CEPH149-IROMC

D7 TO D10: CENTROI CMDSH-3TR
C

OUT

: KEMET T510X477M006AS

: 200kHz

SENSE

FROM

CLKOUT

TG1

SW1

BOOST1

BG1

EXTV

INTV

PGND

BG2

BOOST2

SW2

TG2

AMPMD

M10

M11

GND

150

F, 16V

GND

150

F, 16V

OUT

470

F, 6.3V

OUT

470

F, 6.3V

D3
MBRS
340T3

D2
MBRS
340T3

D1
MBRS
340T3

M12

0.003

D4
MBRS
340T3

0.47

LTC1629-6

0.47

0.33

OPTIONAL SYNC

CLOCK IN

0.01

47k

24k

10k

47pF

75k

6800pF

1000pF

100pF

1000pF

0.47

25V

6.3V

D10

47pF

DIFFOUT

100pF

VID Controlled High Current 70A 4-Phase Application

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LTC1706-61