LTC1706-82 Linear Technology, LTC1706-82 Datasheet - Page 6

• Manufacturer Part Number: LTC1706-82
• Description: VID Voltage Programmer for Intel VRM 9.0
• Manufacturer: Linear Technology

OPERATIO
LTC1706-82
Each VID input pin is pulled up by a 40k resistor in series
with a diode connected to V
grounded (or driven low) to produce a digital low input. It
can be either floated or connected to V
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 un-
wanted stray pickup.
When used with the LTC1629, the LTC1706-82’s FB,
SENSE, V
tively, with the EAIN, V
the LTC1629. The result of this application is a precisely
controlled, multiphase, variable output voltage supply to
any low voltage, high current system such as a powerful
personal computer, workstation or network server. True
remote sense capability of the LTC1629 is also retained in
this case.
VID Input Characteristics
The VID inputs should be driven with a maximum V
0.4V and a minimum V
range is not limited to values less than V
internal diode between V
inputs can go higher than V
V
This allows the LTC1706-82 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 Vcc because of a resistor from
Vcc through a series diode to each one of the VID inputs.
This increase in quiescent current is calculated from
N is the number of grounded VID inputs. V
0.6V while R
In other words, each VID input has a typical pull up current
of (V
system.
6
CC
I
Q
or damaging the input.
CC
= N(V
CC
– 0.6)/40K, which is approximately 68 A for a 3.3V
.
CC
CC
and GND pins should be connected, respec-
PULLUP
– V
DIODE
U
has a typical pullup resistance of 40k.
DIFFOUT
)/R
IH
of 1.6V. However, the VID input
CC
PULLUP
CC
and the pull-up resistor, the
CC
, INTV
without being clamped to
. Therefore, it should be
CC
, and SGND pins of
CC
CC
DIODE
. Because of the
to get a digital
is typically
IL
of
Table 1. VID Inputs and Corresponding Output Voltage
CODE
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111
VID4
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
VID3
GND
GND
GND
GND
GND
GND
GND
GND
Float
Float
Float
Float
Float
Float
Float
Float
GND
GND
GND
GND
GND
GND
GND
GND
Float
Float
Float
Float
Float
Float
Float
Float
VID2
GND
GND
GND
GND
Float
Float
Float
Float
GND
GND
GND
GND
Float
Float
Float
Float
GND
GND
GND
GND
Float
Float
Float
Float
GND
GND
GND
GND
Float
Float
Float
Float
VID1
GND
Float
Float
GND
GND
Float
Float
GND
GND
Float
Float
GND
GND
Float
Float
GND
GND
Float
Float
GND
GND
Float
Float
GND
GND
Float
Float
GND
GND
Float
Float
GND
VID0
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
GND
Float
NO_CPU
(1.075V)
OUTPUT
1.475V
1.275V
1.175V
1.125V
1.100V
1.775V
1.750V
1.725V
1.700V
1.675V
1.650V
1.625V
1.600V
1.575V
1.550V
1.525V
1.500V
1.450V
1.425V
1.400V
1.375V
1.350V
1.325V
1.300V
1.250V
1.250V
1.200V
1.150V
1.850
1.825
1.800