Characteristics of a bubble generator at high temperatures

Generation current margin is found to be limited not only by minimum current but also by maximum current. The generator maximum current IGmaxis measured for a 64 Kbit bubble memory chip with a 3 micron bubble. The chip temperature range was from 0 °C to 70 °C. A considerable loss of current margin is found at high current and high temperatures. This is considered to result from the generation of extra bubbles. IGmaxand its decay are observed to strongly depend on the shape of the generation pulse. A properly selected pulse shape increases IGmaxby 100 mA for a margin decay of less than -4 mA/decade and generate operation becomes possible in wide temperature range without compensation. Design combinations of generator and transfer gate or generator and replicator are proposed to give a more reliable generator port.