Phase change memory word line driver
View Patent ↗A method for improving sub-word line response comprises generating a variable substrate bias determined by at least one user parameter. The variable substrate bias is applied to a sub-word line driver in a selected sub-block of a memory. A voltage disturbance on a sub-word line in communication with the sub-word line driver is minimized by modifying a variable substrate bias of the sub-word line driver to change a transconductance of the sub-word line driver thereby.
1. A method for improving sub-word line response comprising:
generating a variable substrate bias;
applying the variable substrate bias to a sub-word line driver in a selected sub-block of a memory during a write operation;
applying a bias of Vss to sub-word line drivers in the remaining sub-blocks of the memory; and
modifying a variable substrate bias of the sub-word line driver depending on at least one user parameter.
2. The method of claim 1 wherein generating the variable substrate bias includes shunting at least one resistor based on a trim value, each resistor being in series with a bias resistor and dividing a voltage.
3. The method of claim 1 wherein the at least one user parameter is a number of a plurality of memory cells in communication with the sub-word line.
4. The method of claim 1 wherein the at least one user parameter is an address of a plurality of memory cells in communication with the sub-word line.
5. The method of claim 1 wherein the at least one user parameter is an array configuration of a memory comprising a plurality of memory cells in communication with the sub-word line.
6. The method of claim 1 wherein the variable substrate bias voltage is greater than or equal to 0 volts and less than or equal to 0.69 volts.
7. The method of claim 1 , wherein the variable substrate bias voltage is greater than or equal to 0.1 volts and less than or equal to 0.69 volts.
8. The method of claim 1 wherein the variable substrate bias voltage is substantially equal to 0.4 volts.
9. The method of claim 2 wherein the trim value is user programmable.
10. The method of claim 1 , further comprising:
applying a bias of Vss to the sub-word line driver in the selected sub-block of the memory during a read operation.