LOW POWER VLSI
(ECE4008)
REPORT
NAME
BANDI HARI PRIYA
REGISTRATION NUMBER
20BEV7027
VELLORE INSTITUTE OF TECHNOLOGY,
AMARAVATI, AP-522 237, INDIA, DEC.
2021
LIST OF EXPERIMENTS:
S.NO
Name of the Experiment
1.
Verification of basic transistor characteristics (NMOS, PMOS).
2.
Verification of Combinational circuits (Inverter, NAND, NOR).
3.
Comparison of different logic styles (Pseudo NMOS, Enhancement
NMOS, CMOS, Depletion NMOS).
Experiment 3:
Aim:
Comparison of different logic styles (Pseudo NMOS, Enhancement NMOS, CMOS, Depletion
NMOS).
Required Tools:
ngspice
Circuit Diagram of Pseudo NMOS:
Code:
*pseudo NMOS
.include cmos_90nm.txt
.param supply =1.5
Vdd net1 gnd 'SUPPLY'
MN1 out in gnd gnd nmos W=0.5u L=90n
MP1 out gnd net1 net1 pmos W=1u L=90n
c1 out gnd 0.1p
Vin in gnd pulse(0 supply 0 0.5p 0.5p 0.1u 0.2u)
.tran 0.1ns 40ns
.control
run
set color0=white
plot v(out) v(in)
.endc
.end
Output:
Circuit Diagram of Depletion-type NMOS:
Code:
* Circuit Description *
* dc supplies
Vdd 1 0 DC +5V
* input digital signal
Vi 3 0 DC 0V
* MOSFET circuit
M1 2 3 0 0 nmos_enhancement_mosfet L=3um W=9um
M2 1 2 2 0 nmos_depletion_mosfet L=9um W=3um
* mosfet model statements (by default level 1)
.model nmos_enhancement_mosfet nmos (kp=40u Vto=0.7V phi=0.6V gamma=1.1)
.model nmos_depletion_mosfet nmos (kp=40u Vto=-3V phi=0.6V gamma=1.1)
* Analysis Requests *
.DC Vi 0V +5V 20mV
* Output Requests *
.control
run
PLOT V(2)
.endc
.end
Output:
Noise Margin:
the depletion-load inverter the output voltage levels V OL and VOH as 0.112 V and 5 V
Transfer characteristics accounting for the transistor body effect that V IL=0.845 V, VOL=0.112
V and VOH=5V. From graph VIH=1.67 V.
NMH = VOH - VIH = 5 – 1.67 = 3.33 V
NML = VIL - VOL = 0.845 - 0.112 = 0.733 V
Circuit Diagram of Enhancement-type NMOS:
Code:
* Circuit Description *
* dc supplies
Vdd 1 0 DC +5V
* input digital signal
Vi 3 0 DC 0V
* MOSFET circuit
M1 2 3 0 0 nmos_enhancement_mosfet L=3um W=9um
M2 1 1 2 0 nmos_enhancement_mosfet L=9um W=3um
* mosfet model statement (by default level 1)
.model nmos_enhancement_mosfet nmos (kp=40u Vto=0.7V phi=0.6V gamma=1.1)
* Analysis Requests *
.DC Vi 0V +5V 100mV
* Output Requests *
.control
run
Plot V(2)
.endc
.end
Output:
Noise Margin:
Transfer characteristics accounting for the transistor body effect that V IL=0.7 V, VOL=0.24 V
and VOH=3V. From graph VIH=1.78 V.
NMH = VOH - VIH = 3 - 1.78 = 1.27 V
NML = VIL - VOL = 0.7 - 0.24 = 0.46 V