LTC1706-82
VID Voltage Programmer
for Intel VRM9.0/9.1
FEATURES
s
s
DESCRIPTIO
s
s
s
s
Fully Compliant with the Intel VRM9.0/9.1 VID
Specification
Programs Regulator Output Voltage from 1.10V to
1.85V in 25mV Steps
Programs an Entire Family of Linear Technology
DC/DC Converters
±0.25%
Accurate Voltage Divider
Built-In 40k Pull-Up Resistors on Program Inputs
Available in MSOP-10 Packaging
The LTC
®
1706-82 is a precision, digitally programmed,
resistive ladder which adjusts the output of any 0.8V
referenced regulator. Depending on the state of the five
VID inputs, an output voltage between 1.10V and 1.85V is
programmed in 25mV increments.
The LTC1706-82 is designed specifically to program an
entire family of Linear Technology DC/DC converters in full
compliance with the Intel VRM9.0/9.1 specifications.
The LTC1706-82 programs the following Linear Technol-
ogy DC/DC converters: LTC1628, LTC1629, LTC1702,
LTC1735, LTC1735-1, LTC1929 and LTC3729.
For a compact VRM9.0/9.1 solution with up to 60A capa-
bility, see the LTC3732, a 3-phase synchronous controller
with integrated 5-bit VID and MOSFET drivers.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Pentium is a registered trademark of Intel Corporation.
AMD Athlon is a trademark of Advanced Micro Devices, Inc.
APPLICATIO S
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Intel Pentium
®
III Processor Power Supply
Multiprocessor Workstations and Servers
Multiphase Processor Power Supply
AMD Athlon
TM
Processor Power Supply
TYPICAL APPLICATIO
VID Controlled High Current 4-Phase DC/DC Converter (Simplified Block Diagram)
V
IN
4.5V TO 22V
V
IN
INTV
CC
VID0
VID1
FROM
µP
V
CC
SENSE
LTC1629
V
DIFFOUT
SGND
FB
GND
EAIN
TG2
SW2
BG2
V
IN
4.5V TO 22V
V
IN
LTC1629
TG1
SW1
BG1
PGND
SGND
EAIN
NOTE: UP TO SIX LTC1629s CAN BE PARALLELED
TO DELIVER AS MUCH AS 200A
TG2
SW2
BG2
1706-82 TA01
TG1
SW1
BG1
PGND
V
IN
L1
R
SENSE1
VID2 LTC1706-82
VID3
VID4
L2
R
SENSE2
L3
R
SENSE3
V
IN
L4
R
SENSE4
U
+
V
OUT
1.10V TO 1.85V
UP TO 70A
C
OUT
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LTC1706-82
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
VID0
VID1
VID2
VID3
V
CC
1
2
3
4
5
10
9
8
7
6
FB
GND
NC
VID4
SENSE
(Voltages Referred to GND Pin)
Input Supply Voltage (V
CC
) ..........................– 0.3V to 7V
VID Input Pins .............................................– 0.3V to 7V
SENSE Pin ...................................................– 0.3V to 7V
FB Pin ..........................................................– 0.3V to 7V
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Junction Temperature ........................................... 110°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1706EMS-82
MS PART MARKING
LTMJ
MS PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 110°C,
θ
JA
= 200°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
2.7V
≤
V
CC
≤
5.5V, VID0 = VID1 = VID2 = VID3 = VID4 = NC unless otherwise specified.
SYMBOL
V
CC
I
VCC
R
FB-SENSE
V
OUT
Error %
R
PULLUP
VID
T
I
VID-LEAK
V
PULLUP
PARAMETER
Operating Supply Voltage Range
Supply Current
Resistance Between SENSE and FB
Output Voltage Accuracy
VID Input Pull-Up Resistance
VID Input Voltage Threshold
VID Input Leakage Current
VID Pull-Up Voltage
Programmed From 1.10V to 1.85V
V
DIODE
= 0.6V, (Note 4)
V
IL
(2.7V < V
CC
< 5.5V)
V
IH
(2.7V < V
CC
< 5.5V)
V
CC
< VID < 7V, (Note 4)
V
CC
= 3.3V
V
CC
= 5V
1.6
0.01
2.8
4.5
±1.00
(Note 3)
q
q
CONDITIONS
MIN
2.7
TYP
0.1
MAX
5.5
5.0
14
0.25
UNITS
V
µA
kΩ
%
kΩ
V
V
µA
V
V
6
– 0.25
10
40
0.4
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The LTC1706-82 is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the – 40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3:
With all five VID inputs floating, the V
CC
supply current is simply
the device leakage current. However, the V
CC
supply current will rise and
be approximately equal to the number of grounded VID input pins times
(V
CC
– 0.6V)/40k. (See the Applications Information section for more
detail.)
Note 4:
Each built-in pull-up resistor attached to the VID inputs also has a
series diode connected to V
CC
to allow input voltages higher than the V
CC
supply without damage or clamping. (See Operation section for further
details.)
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W
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LTC1706-82
TYPICAL PERFOR A CE CHARACTERISTICS
Typical Error % vs Output Voltage
0.25
T
A
= 25°C
ERROR (%)
0
ERROR (%)
–0.25
1.1
1.2
1.3 1.4 1.5 1.6 1.7
OUTPUT VOLTAGE (V)
1.8
1706-82 G01
R
FB1
vs Temperature
30
150
130
110
90
70
50
0
–50
20
R
FB1
(kΩ)
10
VID PULL-UP CURRENT (µA)
0
50
TEMPERATURE (°C)
Supply Current vs Temperature
2.0
ALL VID INPUTS OPEN
5
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
1.5
1.0
V
CC
= 5V
0.5
V
CC
= 3.3V
0
–50
0
50
TEMPERATURE (°C)
U W
Typical Error % vs Temperature
0.25
V
OUT
= 1.1V
V
OUT
= 1.5V
V
OUT
= 1.85V
0
–0.25
–50
0
50
TEMPERATURE (°C)
100
1706-82 G02
I
VID-PULLUP
vs Temperature
V
CC
= 5V
VID4 = 0V
VID0 = VID1 = VID2 = VID3 = OPEN
100
1706-82 G03
30
–50
0
50
TEMPERATURE (°C)
100
1706-82 G04
Supply Current vs Supply Voltage
ALL VID INPUTS OPEN
T
A
= 25°C
4
3
2
V
CC
= 2.7V
1
100
1706-82 G05
0
0
2
4
6
SUPPLY VOLTAGE (V)
8
1706-82 G06
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LTC1706-82
PI FU CTIO S
VID0 (Pin 1):
LSB Programming Input. Low = GND,
High = V
CC
or Float. Grounding VID0 adds 25mV to the
output sense voltage.
VID1 (Pin 2):
4th MSB Programming Input. Low = GND,
High = V
CC
or Float. Grounding VID1 adds 50mV to the
output sense voltage.
VID2 (Pin 3):
3rd MSB Programming Input. Low = GND,
High = V
CC
or Float. Grounding VID2 adds 100mV to the
output sense voltage.
VID3 (Pin 4):
2nd MSB Programming Input. Low = GND,
High = V
CC
or Float. Grounding VID3 adds 200mV to the
output sense voltage.
V
CC
(Pin 5):
Power Supply Voltage. Range from 2.7V to
5.5V.
SENSE (Pin 6):
Regulator Output Voltage. Connect di-
rectly to regulator output sense node or V
DIFFOUT
when
used with the LTC1629 and LTC1929.
VID4 (Pin 7):
MSB Programming Input. Low = GND,
High = V
CC
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 0.8V feedback
pin of a compatible regulator or the EAIN pin of the
LTC1629, LTC1929 and LTC3729.
PI TABLE
PIN
1
2
3
4
5
6
7
8
9
10
NAME
VID0
VID1
VID2
VID3
V
CC
SENSE
VID4
NC
GND
FB
Ground
0.8V Feedback Input
0
0
0.8
1.075
– 0.3
– 0.3
7
7
DESCRIPTION
LSB Programmable Input
4th MSB Programmable Input
3rd MSB Programmable Input
2nd MSB Programmable Input
Power Supply
Regulator Output Voltage
MSB Programmable Input
NOMINAL (V)
MIN
TYP
MAX
0
0
0
0
2.7
1.075
0
V
CC
V
CC
V
CC
V
CC
5.5
1.85
V
CC
ABSOLUTE MAX (V)
MIN
MAX
– 0.3
– 0.3
– 0.3
– 0.3
– 0.3
– 0.3
– 0.3
7
7
7
7
7
7
7
4
U
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U
U
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LTC1706-82
BLOCK DIAGRA
V
CC
40k
VID0 1
V
CC
V
CC
5
40k
VID1 2
V
CC
SWITCH
CONTROL
LOGIC
40k
VID2 3
R
FB2
R
FB1
10k
V
CC
40k
VID3 4
VID4 7
OPERATIO
The LTC1706-82 is a precision resistive divider designed
specifically for use with an entire family of Linear Technol-
ogy Corporation DC/DC switching regulators with 0.8V
internal reference and feedback voltages. The LTC1706-82
produces an output voltage ranging from 1.10V to 1.85V
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.
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
.
W
6
SENSE
10 FB
9
GND
1706-82 BD
V
CC
40k
U
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. VID4 is the most
significant bit (MSB) and VID0 is the least significant bit
(LSB).
When the five VID inputs are low, or grounded, the
regulator output voltage is set to 1.85V. Each increasing
binary count is equivalent to a decrease of 25mV in the
output voltage. Therefore, to obtain a 1.10V output, only
VID0 is grounded while the other four VID inputs are tied
high or floating.
When all five VID inputs are high or floating, such as when
no CPU is present in a system, a regulated 1.075V output
is generated at V
SENSE
.
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