OTP scheme with multiple magnetic tunnel junction devices in a cell

摘要

A one time programming (OTP) apparatus unit cell includes multiple magnetic tunnel junctions (MTJs) and a shared access transistor coupled between the multiple MTJs and a fixed potential. Each of the multiple MTJs in a unit cell can be coupled to separate programming circuitry and/or separate sense amplifier circuitry so that they can be individually programmed and/or individually sensed. A logical combination from the separate sense amplifiers can be generated as an output of the unit cell.

主权项

1. A one time programmable memory array unit cell, comprising:
an access transistor having a source node and a drain node, one of the source node and the drain node being coupled to a fixed potential, and to allow for programming and sensing; a first magnetic tunnel junction device coupled between the other of the source node and the drain node of the access transistor and a first bit line in the one time programmable memory array unit cell; a second magnetic tunnel junction device coupled between the other of the source node and the drain node of the access transistor and a second bit line in the one time programmable memory array unit cell; a first sense amplifier coupled to the first bit line; a second sense amplifier coupled to the second bit line; logical OR gate circuitry comprising a first OR gate input coupled to an output of the first sense amplifier and a second OR gate input coupled to an output of the second sense amplifier; and programming circuitry coupled to the first magnetic tunnel junction device and to the second magnetic tunnel junction device, the programming circuitry configured for sequentially coupling the first magnetic tunnel junction device to a first voltage source, decoupling the second magnetic tunnel junction device from the first voltage source and then coupling the second magnetic tunnel junction device to the first voltage source, and decoupling the first magnetic tunnel junction from the first voltage source, wherein the first voltage source is sufficient to break down a first barrier layer associated with the first magnetic tunnel junction device and second barrier layer associated with the second magnetic tunnel junction device, the programming circuitry further configured for decoupling the first voltage source from the first magnetic tunnel junction device and the second magnetic tunnel junction device when either of the first sense amplifier and the second sense amplifier is enabled.