X9311

The X9311 is a solid state nonvolatile potentiometer and is ideal for digitally controlled resistance trimming. The X9311 is a resistor array composed of 99 resistive elements. Between each element and at either end are tap points accessible to the wiper element. The position of the wiper element is controlled by the CS, U/D, and INC inputs. The position of the wiper can be stored in nonvolatile memory and then be recalled upon a subsequent power-on operation. The resolution of the X9311 is equal to the maximum resistance value divided by 99. As an example, tor the X9311U (50 KQ) each tap point represents 5059. All Xicor nonvolatile memories are designed and tested for applications requiring extended endurance and data retention.

The features of x9311 are compatible with X9MME and X9CMME, low power COMS (active current, 3 mA max; standby current, 500 A max), 99 resistive element (temperature compensated; ±20% end to end resistance range, 0 to 10v range), 100 wiper tap points (wiper positioned via three wire interface, similar to TTL up/down counter, wiper position stored in nonvolatile memory and recalled on power-up), 100 year wiper position data retention, X9311Z = 1K OHMS, X9311W = 10K OHMS, X9311 = 50K OHMS, X9311T = 100K OHMS

There are three basic sections of the X9311; 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 99 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 INC, U/D and CS inputs control the revetment of the wiper along the resistor array. With CS set low the X9911 ingested 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 seven bit counter. The output of this counter is decoded to select one of one-hundred wiper positions along the resistive array. 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. The value of the counter is stored in nonvolatile memory whenever CS transitions high while the input is also high. When the X9311 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 counter is reset to the value last stored.