ISL95710 Intersil Corporation, ISL95710 Datasheet - Page 6

• Manufacturer Part Number: ISL95710
• Description: 128 Taps Up/Down Interface
• Manufacturer: Intersil Corporation

A.C. Timing
Power Up and Down Requirements
In order to prevent unwanted tap position changes, or an
inadvertent store, bring the CS and INC high before or
concurrently with the V
potentiometer voltages must be applied after this sequence
is completed. During power-up, the data sheet parameters
for the DCP do not fully apply until 1ms after V
final value. The V
Pin Descriptions
R
The high (R
equivalent to the fixed terminals of a mechanical
potentiometer. The terminology of R
relative position of the terminal in relation to wiper movement
direction selected by the U/D input and not the voltage
potential on the terminal.
R
R
terminal of a mechanical potentiometer. The position of the
wiper within the array is determined by the wiper counter.
Up/Down (U/D)
The U/D input controls the direction of the wiper movement
and whether the wiper counter is incriminated or
decremented.
Increment (INC)
The INC input is negative-edge triggered. Toggling INC will
move the wiper and either increment or decrement the wiper
counter in the direction indicated by the logic level on the
U/D input.
w
W
H
is the wiper terminal and is equivalent to the movable
and R
INC
U/D
CS
R
W
L
H
) and low (R
t
CI
CC
t
IW
Note (1): MI in the timing diagram refers to the minimum incremental change in the wiper position.
ramp spec is always in effect.
CC
L
pin on power-up. The
) terminals of the ISL95710 are
t
IL
t
ID
6
t
CYC
L
and R
t
IH
H
references the
CC
t
DI
reaches its
t
IC
MI
(1)
ISL95710
t
Chip Select (CS)
The device is selected when the CS input is LOW. The
current wiper counter value is stored in nonvolatile memory
when CS is returned HIGH while the INC input is also HIGH.
After the store operation is complete the ISL95710 will be
placed in the low power standby mode until the device is
selected once again.
Principles of Operation
There are three sections of the ISL95710: the input control,
wiper counter and decode section; the nonvolatile memory;
and the resistor array. The input control section operates as
an up/down counter. The output of this wiper counter is
decoded to turn on a electronic switch connecting a point on
the resistor array to the wiper output. The contents of the
wiper counter can be stored in nonvolatile memory and
retained for future use. The resistor array is comprised of
individual resistors connected in series. At either end of the
array and between each resistor is an electronic switch that
transfers the potential at that point to the wiper.
The wiper, when at either fixed terminal, acts like its
mechanical equivalent and does not move beyond the last
position. The wiper counter does not wrap around when
clocked to either extreme.
The electronic switches on the device operate in a “make
before break” mode when the wiper changes tap positions. If
the wiper is moved several positions, multiple taps are
connected to the wiper for t
R
a significant amount if the wiper is moved several positions.
When the device is powered-down, the last wiper position
stored will be maintained in the nonvolatile memory. When
CPHS
TOTAL
value for the device can temporarily be reduced by
t
F
90%
10%
90%
IW
(INC to R
t
R
W
t
CPHNS
change). The
August 17, 2005
FN8240.2