SPICE simulation on 2PASCL 4x4 bit array multiplier

Nazrul Anuar

Graduate School of Engineering, Gifu University, Gifu, 501-1193 Japan

AbstractThe paper presents a SPICE simulation on 2PASCL 4x4 bit

array multiplier.

1 4x4 array multiplier1.1 Simulation and results

Previously, a preliminary study has been done on the4x4 bit array multiplier as shown in Fig. 1 and Fig. 2.After considering the type of combination circuit forhalf adders and full adders as shown in Fig. 3 and Fig.4, we simulate a full 2PASCL 4x4 bit array multiplierusing 0.18 µm standard CMOS process. The 4x4 bitarray multipler simulated in this paper are using 4 halfadders, 8 full adders, 16 NANDs and 16 NOT circuits.All are using 2PASCL topologies. The block diagramof 4x4 bit array 2PASCL multiplier is demonstrated inFig. 5, which is taken from SPICE simulation circuitdiagram. The simulation results for 1 MHz transitionfrequency at are as shown in Fig. 6. The result for(1111)2 x (1111)2 = (11100001)2 is used to check theresult.

Fig. 1 Multiplication of two 4-bit words.

Fig. 2 Details for a 4x4 array multiplier.

A

B

Cout=AB

S=(A+B)+ABA+B

AB

AB

Fig. 3 Half adder which consist of NOR, NAND andNOT logic.

A

B

S=(A�B) + cin

Cout=AB(A+B)cin

A�B

cin(A�B)

AB

Cin

Fig. 4 Full adder which consist of XOR and NANDlogics.

2 ConclusionFrom the simulation results, 4x4 bit array 2PASCL

at 1 MHz transition frequency shows that circuit isoperated well. This proofs that the circuit diagram iscorrect. The output waveforms will be improved in thenext simulation report. The next simulation will bethe calculation of the energy and a comparison with4x4 bit array CMOS multiplier.

X1ABphiphi-

Y

X2ABphiphi-

Y

X3ABphiphi-

Y

X4ABphiphi-

Y

X5ABphiphi-

Y

X6ABphiphi-

Y

X7ABphiphi-

Y

X8ABphiphi-

Y

X9ABphiphi-

Y

X10ABphiphi-

Y

X11ABphiphi-

Y

X12ABphiphi-

Y

X13ABphiphi-

Y

X14ABphiphi-

Y

X15ABphiphi-

Y

X16ABphiphi-

Y

HAAB

phi

phi-CS

HAAB

phi

phi-CS

HAAB

phi

phi-CS

X20ABCinphiphi-

CS

X21ABCinphiphi-

CS

X22ABCinphiphi-

CS

X23ABCinphiphi-

CS

X24ABCinphiphi-

CS

X25ABCinphiphi-

CS

X26ABCinphiphi-

CS

X27ABCinphiphi-

CS

HAAB

phi

phi-CS

A

B

phi

-phi

P0

P1

P2

P3

P4

P5

P6

P7

.tran 0 4u 0 0.1n

Fig. 5 4x4 array multiplier block diagram.

0.0us 0.4us 0.8us 1.2us 1.6us 2.0us 2.4us 2.8us 3.2us 3.6us 4.0us0.3V1.1V1.8V0.3V1.1V1.8V0.3V1.1V1.8V0.3V0.9V1.5V0.3V0.9V1.5V

0.35V0.70V1.05V

350mV650mV950mV

0.3V1.1V1.8V0.0V0.9V1.8V0.0V0.9V1.8V0.0V0.9V1.8V

V(p7)

V(p6)

V(p5)

V(p4)

V(p3)

V(p2)

V(p1)

V(p0)

V(n002)

V(n001)

V(n003) V(n004)

Fig. 6 Output waveforms.