US 2014/0153325 A1 · BODY VOLTAGE SENSING BASED SHORT PULSE READING CIRCUIT

Abstract

As memory geometries continue to scale down, current density of magnetic tunnel junctions (MTJs) make conventional low current reading scheme problematic with regard to performance and reliability. A body-voltage sense circuit (BVSC) short pulse reading (SPR) circuit is described using body connected load transistors and a novel sensing circuit with second stage amplifier which allows for very short read pulses providing much higher read margins, less sensing time, and shorter sensing current pulses. Simulation results (using 65-nm CMOS model SPICE simulations) show that our technique can achieve 550 mV of read margin at 1 ns performance under a 1V supply voltage, which is greater than reference designs achieve at 5 ns performance.

Claims20

Dependent claims

A body voltage based sense circuit (BVSC) apparatus for short pulse reading (SPR) of a memory, said apparatus comprising:

a body voltage sensing data circuit configured to sense resistance of a memory cell that has two states, said body voltage sensing data circuit having a voltage output in response to short pulse reading (SPR) of said memory cell;
said body voltage sensing data circuit configured to translate the states of the memory cell into a sense data voltage signal;
a body voltage sensing reference circuit configured to generate a sense reference voltage signal;
a second stage sense amplifier configured to compare said sense data voltage signal and said sense reference voltage signal and output a data signal;
and
a capturing latch circuit configured to capture said data signal using positive feedback;
wherein said captured data signal digitally represents the state of said memory cell as a binary output;
and
wherein said body voltage sensing is performed on a body-connected load that provides a high sensing margin (SM) in which body and drain terminals of a transistor of said body voltage sensing data circuit are coupled together.

6 more elements

A body voltage based sense circuit (BVSC) apparatus for short pulse reading (SPR) of a memory, said apparatus comprising:

a body voltage sensing data circuit for sensing resistance of a magnetic tunnel junction memory cell having two states, said body voltage sensing data circuit having a voltage output in response to short pulse reading (SPR) of said memory cell;
said body voltage sensing data circuit configured to translate the states of the magnetic tunnel junction memory cell into a sense data voltage signal;
a body voltage sensing reference circuit for sensing resistance of a reference magnetic tunnel junction memory cell and translating this into a sense reference voltage signal;
a second stage sense amplifier configured to compare said sense data voltage signal and said sense reference voltage signal and output a data signal;
and
a capturing latch configured for capturing said data signal, as a captured data signal, using positive feedback;
wherein said captured data signal digitally represents the state of said memory cell as a binary output;
and
wherein said body voltage sensing is performed on a body-connected load that provides a high sensing margin (SM) in which body and drain terminals of a transistor of said body voltage sensing data circuit are coupled together.

6 more elements

Dependencies are inferred from the claim text.

Body voltage sensing based short pulse reading circuit

Life of this patent

Body voltage sensing based short pulse reading circuit

Life of this patent

Abstract

Claims20