Characteristics for 4Mb ion-implanted bubble memory modules

A 4Mb module with a 4Mb on-chip-cache ion-implanted bubble memory chip has been developed. Operation temperature characteristics for the module are evaluated for total operation with fully loaded data. A temperature coefficient for the bias field in the module is adjusted to that for the chip by using a pair of rare earth magnets with large and small temperature coefficients. The acceptable high temperature limit for the module operation is obtained by restricting the number of consecutive minor-minor gate operation to 8 pages. Consequently, reasonable total operation margins are confirmed in a temperature range from -10 to 60°C without any modification for operation conditions.