The Intersil X90100 is a non-volatile electronically
programmable capacitor. The device is programmed through
a simple digital interface. After programming, the chosen
setting for the device is retained by internal EEPROM
storage whether or not DC power is maintained. There are
32 programmable capacitance values selectable, ranging
from 7.5pF to 14.5pF in 0.23pF increments, in single-ended
mode. The dielectric is highly stable, and the capacitance
exhibits a very low voltage coefficient. It has virtually no
dielectric absorbtion and has a very low temperature drift
coefficient in differential mode (<50ppm/°C).
The X90100 is programmed through three digital interface
pins, which have Schmitt triggers and pullup resistors to
secure code retention. The three pins, INC, U/D, and CS,
are identical in operation to other Intersil chips with up/down
interface, such as the X9315 5-bit Digitally Controlled
Potentiometer (DCP).