X93156UM8IZ-2.7 Intersil, X93156UM8IZ-2.7 Datasheet - Page 6

• Manufacturer Part Number: X93156UM8IZ-2.7
• Description: IC XDCP 32-TAP 50K 3-WIRE 8-MSOP
• Manufacturer: Intersil
• Series: XDCP™r

Specifications of X93156UM8IZ-2.7

• Taps: 32
• Resistance (ohms): 50K
• Number Of Circuits: 1
• Temperature Coefficient: 35 ppm/°C Typical
• Memory Type: Non-Volatile
• Interface: Up/Down (3-Wire)
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Resistance In Ohms: 50K
• Track Taper: Linear
• Resistance Tolerance: ± 25%
• No. Of Steps: 32
• Supply Voltage Range: 2.7V To 5.5V
• Control Interface: 3 Wire, Serial
• No. Of Pots: Single
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Principles of Operation
There are three sections of the X93156: the input control,
counter and decode section; the nonvolatile memory; and
the resistor array. The input control section operates just like
an up/down counter. The output of this counter is decoded to
turn on a single electronic switch connecting a point on the
resistor array to the wiper output. Under the proper
conditions the contents of the counter can be stored in
nonvolatile memory and retained for future use. The resistor
array is comprised of 31 individual resistors connected in
series. At either end of the array and between each resistor
is an electronic switch that transfers the connection 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. That is, the counter does not wrap around when
clocked to either extreme.
If the wiper is moved several positions, multiple taps are
connected to the wiper for t
2-terminal resistance value for the device can temporarily
change by 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
power is restored, the contents of the memory are recalled
and the wiper is set to the value last stored.
Instructions and Programming
The INC, U/D and CS inputs control the movement of the
wiper along the resistor array. With CS set LOW the device
is selected and enabled to respond to the U/D and INC
inputs. HIGH to LOW transitions on INC will increment or
decrement (depending on the state of the U/D input) a five
bit counter. The output of this counter is decoded to select
one of thirty two wiper positions along the resistive array.
The value of the counter is stored in nonvolatile memory
whenever CS transitions HIGH while the INC input is also
HIGH. In order to avoid an accidental store during power-up,
CS must go HIGH with V
left open, the CS pin is internally pulled up to V
internal 30k resistor.
The system may select the X93156, move the wiper and
deselect the device without having to store the latest wiper
position in nonvolatile memory. After the wiper movement is
performed as described above and once the new position is
reached, the system must keep INC LOW while taking CS
HIGH. The new wiper position will be maintained until
changed by the system or until a power-up/down cycle
recalled the previously stored data. In order to recall the
stored position of the wiper on power-up, the CS pin must be
held HIGH.
CC
IW
during initial power-up. When
6
(INC to V
W
change). The
CC
by an
X93156
Mode Selection
This procedure allows the system to always power-up to a
preset value stored in nonvolatile memory; then during
system operation minor adjustments could be made. The
adjustments might be based on user preference, system
parameter changes due to temperature drift, or other system
trim requirements.
The state of U/D may be changed while CS remains LOW.
This allows the host system to enable the device and then
move the wiper up and down until the proper trim is attained.
Symbol Table
CS
H
L
L
WAVEFORM
INC
H
X
L
L
L
U/D
H
H
L
X
X
X
L
Wiper Up
Wiper Down
Store Wiper Position
Standby Current
No Store, Return to Standby
Wiper Up (not recommended)
Wiper Down (not recommended)
INPUTS
Must be
steady
May change
from Low to
High
May change
from High to
Low
Don’t Care:
Changes
Allowed
N/A
MODE
OUTPUTS
Will be
steady
Will change
from Low to
High
Will change
from High to
Low
Changing:
State Not
Known
Center Line
is High
Impedance
November 21, 2007
FN8182.3