Annamacharya Institute Of Technology And Sciences

Department of

Electronics and Communication EngineeringIntegration of spin-ram technology in FPGA circuits

V.PRIYANKA,14701A0466.

contents

• Introduction• What is spin-RAM?• Architecture and Woking of FPGA• Spin-RAM based logic components• Advantages & Disadvantages• Conclusion• References

Introduction

• Most FPGA circuits use SRAM based configuration and flip flops as internal memory.

• Since SRAM is volatile it information stored in memory is lost when it is turned off spin-RAM technology is used .

• Spin-ram technology can be re-programmed more than 10^12 times and has a large retention time of up to 10 years .

What is spin-RAM ?

• Magnetic tunnel junction is used as the storage element in spin-RAM.

• It mainly composed of three layers , two oxide layers and one oxide barrier.

• A MTJ behaves as a resistor depending on the magnetization direction in ferromagnetic layers.

(a)Low resistance MTJ(b)High resistance MTJ

The MTJ stage changes from parallel(P) to Anti-parallel (AP) if the positive direction current density I>Ic , its state will return if the negative direction current density I>Ic.

Architecture of FPGA

How FPGA WORKS

FPGA’s with different packages

Types of memory in FPGA circuit

There are two types of FPGA circuits. They are 1.LUT(look up table) 2.Flip-Flops

MASTER –SLAVE

FLIP-FLOP

LUT

Spin -ram based logic components

• One bit distributed spin-RAM in FPGA circuit.• Spin-ram based interconnection switch and

LUT.• Spin-RAM based flip-flop.

One bit distributed spin-RAM in FPGA circuit

Sensing structure of spin–RAM based FPGA:• The cell sense the magnetic information by

briefly turning on the MN2 switch.• It takes 200ps of time to realize a real “instant

on”.

Sensing structure of spin-ram based FPGA

Writing structure of one bit distributed spin-RAM

Complete one bit distributed spin-RAM

Spin-RAM based interconnection switch and LUT

• The interconnection switch memorizes the connection between the logic elements .

• In a conventional FPGA circuit , the structure of interconnection includes six transistors and six SRAM which must be programmed at the circuit start-up.

Structure of interconnection based on SRAM and spin-ram

Spin-RAM based Flip-Flops

• In a FPGA circuit , the flip-flops are used as registers to temporarily store the results proceeded and synchronize them with the global clock.

• SRAM based master-slave is widely used in current FPGA circuit implementations.

• The Master and slave parts are both clock controlled latches.

Spin-RAM based Flip-Flop

Advantages

• Non-volatility• High speed• Low power dissipation• High density

DISADVATAGES

• FPGAs are generally slower than application –specific integrated circuit(ASIC).

• It can’t handle complex designs.• It draws more power

Conclusion

Therefore it could be advantageously used in the field of aviation and space where security of information is most important.

REFERENCES•S.Brown et al, Kluwer Academic Publishers Paul Chow, IEEE Transactions on VLSI System•V.Stojanovic, IEEE Journal of solid-state circuits •Kevin Morris, FPGA and Programmable Logic Journal •A.Fert et al, Journal of Magnetism and Magnetic Materials •M.Hosomi e tal, IEEE International Electron Devices • J.Hayakawa et al, Japanese Journal of Applied physics