Integrated circuit system with non-volatile memory stress suppression and method of manufacture thereof
An integrated circuit system, and a method of manufacture thereof, including: an integrated circuit die; a non-volatile memory cell in the integrated circuit die and having a bit line for reading a data condition state of the non-volatile memory cell; and a voltage clamp in the integrated circuit die, the voltage clamp having a semiconductor switch connected to the bit line for reducing voltage excursions on the bit line.
1. A memory device comprising:
a memory array configured to include a plurality of memory cells;
a controller configured to connect to the memory array via a plurality of word lines;
an interface configured to connect to the memory array via a plurality of bit lines and detect whether a memory cell is in a low resistive state or a high resistive state during a memory read operation; and
a limiter configured to connect to the plurality of bit lines and to limit or clamp a voltage to a predetermined threshold level when the interface detects that the memory cell is in the high resistive state,
wherein the interface includes a set/reset driver connected to the limiter,
wherein the set/reset driver is disabled during the memory read operation, and
wherein the limiter does not limit or clamp the voltage when the interface detects that the memory cell is in the low resistive state.
2. The memory device as claimed in claim 1 , wherein the limiter includes a diode connected to a switch, and wherein the switch is between a bit line included in the plurality of bit lines and the diode.
3. The memory device as claimed in claim 1 , wherein the limiter includes a semiconductor current sink connected to a switch, and wherein the switch is between a bit line included in the plurality of bit lines and the semiconductor current sink.
4. The memory device as claimed in claim 1 , wherein the limiter includes a noise immune semiconductor current sink connected to a switch, and wherein the switch is between a bit line included in the plurality of bit lines and the noise immune semiconductor current sink.
5. The memory device as claimed in claim 1 , wherein the limiter includes a resistive compensation device connected to a switch, and wherein the switch is between a bit line included in the plurality of bit lines and the resistive compensation device.
6. The memory device as claimed in claim 1 , wherein the limiter is connected between a bit line included in the plurality of bit lines and a ground.
7. The memory device as claimed in claim 6 , wherein the limiter includes a diode connected between a switch and the ground, the diode forward-biased to the ground.
8. The memory device as claimed in claim 6 , wherein the limiter includes:
a semiconductor current sink connected between a switch and the ground; and
an operational amplifier connected to the semiconductor current sink.
9. The memory device as claimed in claim 8 , wherein a non-inverting input of the operational amplifier is connected to the switch and to the semiconductor current sink.
10. The memory device as claimed in claim 9 , wherein an inverting input of the operational amplifier is connected to a reference voltage.
11. The memory device as claimed in claim 6 , wherein the limiter includes a noise immune semiconductor current sink connected between a switch and the ground.
12. The memory device as claimed in claim 11 , wherein the noise immune semiconductor current sink includes at least one of a transistor, a field effect transistor (FET), a P-type pass gate switch device, a P-channel FET device, and a PMOS device.
13. The memory device as claimed in claim 11 , wherein a gate of the noise immune semiconductor current sink is connected to a reference voltage.
14. The memory device as claimed in claim 6 , wherein the limiter includes:
a thermal sensitive resistor connected between a switch and the ground.
15. The memory device as claimed in claim 6 , wherein the limiter includes a resistive compensation device connected between a switch and the ground.
16. The memory device as claimed in claim 15 , wherein the resistive compensation device is at least one of a silicon iron temperature stable resistor, a stabistor, and a temperature varying resistance thermistor.
17. The memory device as claimed in claim 6 , wherein the limiter includes a negative coefficient Zener diode connected between a switch and the ground.
18. The memory device as claimed in claim 1 , wherein the memory array, the controller, the interface and the limiter are formed in an integrated circuit die.
19. The memory device as claimed in claim 1 , wherein the memory cells are non-volatile memory cells, wherein the limiter does not limit or clamp the voltage for as long as the interface detects that the memory cell is in the low resistive state during the memory read operation, and wherein the limiter includes an operational amplifier.
20. The memory device as claimed in claim 1 , further comprising:
a current source to generate a reference current, wherein the interface includes:
a sense amplifier to generate voltages or currents for the memory read operation and to detect whether the memory cell is in the low resistive state or the high resistive state during the memory read operation by comparing the reference current to a sensed current of one of the plurality of bit lines, wherein the reference current represents a threshold resistance value of the memory cell and the sensed current represents a sensed resistance value of the memory cell, wherein the set/reset driver generates voltages or currents for a memory write operation.