2

FN8156.0

February 2, 2005

Block Diagram

Cm

U/D

INC

CS

Cp

Power On Reset

Pin Descriptions

MSOP

SYMBOL

BRIEF DESCRIPTION

1INC

Increment (INC). The INC input is negative-edge triggered. Toggling INC will move the capacitance value and

either increment or decrement the counter in the direction indicated by the logic level on the U/D input.

2U/D

Up/Down (U/D). The U/D input controls the direction of the trimmed capacitor value and whether the counter

is incremented or decremented.

Ground.

4Cp

Cp. The high (Cp) and low (Cm) terminals of the X90100 are equivalent to the fixed terminals of a mechanical

trimmable capacitor. The minimum dc voltage is VSS and the maximum is VCC. The value of capacitance

across the terminals is determined by digital inputs INC, U/D, and CS.

5Cm

Cm. The high (Cp) and low (Cm) terminals of the X90100 are equivalent to the fixed terminals of a mechanical

trimmable capacitor. The minimum dc voltage is VSS and the maximum is VCC. The value of capacitance

across the terminals is determined by digital inputs INC, U/D, and CS.

6N/C

Not Connected. Must be floating.

7CS

Chip Select (CS). The device is selected when the CS input is LOW. The current 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 X90100 will be placed in the low power standby mode until the device is selected once again.

Positive Supply Voltage.

X90100