LTC1706-82 View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC1706-82 Datasheet PDF : 8 Pages
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BLOCK DIAGRA
VCC
VID0 1
40k
VCC
VID1 2
40k
VCC
VID2 3
40k
VCC
40k
VID3 4
VCC
5
VCC
40k
VID4 7
SWITCH
CONTROL
LOGIC
LTC1706-82
6 SENSE
RFB1
10k
10 FB
RFB2
9 GND
1706-82 BD
U
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, RFB1, connected between
SENSE and FB, is typically 10k and is not modified by the
state of the VID program inputs.
The “bottom” feedback resistor, RFB2, however, is modi-
fied by the five VID inputs and is precisely ratioed to RFB1.
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 VSENSE.
170682fa
5
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