X90100M8I Intersil, X90100M8I Datasheet - Page 6

• Manufacturer Part Number: X90100M8I
• Description: IC DIGITAL CAPACITOR NV 8-MSOP
• Manufacturer: Intersil

Specifications of X90100M8I

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

and retained for future use. The capacitor array is comprised
of 31 individual capacitors connected in parallel. At one end
of each element is an electronic switch that connects it to the
sum.
The capacitor, when at either end of the range, 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.
The electronic switches on the device operate in a “make
before break” mode when the counter changes positions. If
the counter is moved several positions, multiple units are
connected to the total for t
C
a significant amount if the counter is moved several
positions.
When the device is powered-down, the last counter position
stored will be maintained in the nonvolatile memory. When
power is restored, the contents of the memory are recalled
and the capacitor is set to the value last stored.
Instructions and Programming
The INC, U/D and CS inputs control the movement of the
capacitor total value. 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 capacitor combinations for the capacitor array.
The value of the counter is stored in nonvolatile memory
whenever CS transitions HIGH while the INC input is also
HIGH.
Table of Values
TOTAL
value for the device can temporarily be increased by
X90100
Example of a single-ended circuit
C
C
m
p
IW
(INC to C
C
6
OUT
=
Single-Ended Mode
0 ≤ Code ≤ 31
Code
TOTAL
31
X1
X2
• 7.0 + 7.5 (pF)
Oscillator
change). The
Circuit
X90100
The system may select the X90100, move the capacitor
value and deselect the device without having to store the
latest count total in nonvolatile memory. After the count
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 C
maintained until changed by the system or until a power-
up/down cycle recalled the previously stored data.
This procedure allows the system to always power-up to a
preset value stored in nonvolatile memory; then during
system operation minor adjustments can be made. The
adjustments might be based on user preference, system
parameter changes due to temperature drift, etc.
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 counter up and down until the proper trim is
attained.
Mode Selection
C
OUT
CS
H
L
L
= Code • 0.35 + 1.00 (pF)
X90100
Differential Mode
0 ≤ Code ≤ 31
Example of a differential mode circuit
INC
H
X
L
L
L
C
C
m
p
U/D
H
X
X
X
H
L
L
Cap Value Up
Cap Value Down
Store Cap Position
Standby Current
No Store, Return To Standby
Cap Value Up (not recommended)
Cap Value Down (not recommended)
C
C
p
s
TOTAL
Oscillator
MODE
Circuit
value will be
February 2, 2005
FN8156.0