Manual of Ring Oscillator.
EXPRIMENT NO.:-7
AIM:- Design and Simulation of Ring Oscillator.
HARDWARE USED: - Computer
SOFTWARE USED:- Tanner EDA
BASIC CIRCUIT:-
Figure: 1 simple Ring oscillator
INTRODUCTION:-
The ring oscillator is a distributed version of the delay oscillator. The ring oscillator uses an odd
number of inverters to give the effect of a single inverting amplifier with a gain of greater than
one. Rather than having a single delay element, each inverter contributes to the delay of the
signal around the ring of inverters, hence the name ring oscillator. Adding pairs of inverters to
the ring increases the total delay and thereby decreases the oscillator frequency. Changing the
supply voltage changes the delay through each inverter, with higher voltages typically decreasing
the delay and increasing the oscillator frequency.
Jitter:-
Period of ring oscillator vibrates in a random manner T=T+T' where T' is a random value. In
high-quality circuits range of T' is relatively small compared to T. This variation in oscillator
period is called jitter. Local temperature effects cause the period of a ring oscillator to wander
above and below the long-term average period. When the local silicon is cold, the propagation
delay is slightly shorter, causing the ring oscillator to run at a slightly higher frequency, which
eventually raises the local temperature. When the local silicon is hot, the propagation delay is
slightly longer, causing the ring oscillator to run at a slightly lower frequency, which eventually
lowers the local temperature.
Department of Electronics and Comm.Enggneering.SDITS, Khandwa Page 1
Manual of Ring Oscillator.
DESIGN CIRCUIT OF RING OSCILLATOR:-
Figure: 2 design a Ring oscillator
T-SPICE CODE:-
SPICE netlist written by S-Edit Win32 Demo 9.12
Written on Jan 27, 2013 at 10:55:02
.dc lin source v16 0 5 0.1
.include "C:\Program Files\Tanner EDA\Demo\T-Spice\models\ml5_20.md"
.print dc v(in) v(out)
Waveform probing commands
.probe
.options probefilename="File2.dat"
probesdbfile="C:\Program Files\Tanner EDA\Demo\T-Spice\File2.sdb"
probetopmodule="Module0"
Main circuit: Module0
C1 N16 Gnd 10pF
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Manual of Ring Oscillator.
o C2 N25 Gnd 10pF
o C3 N36 Gnd 10pF
M4 N16 N34 Gnd Gnd NMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M5 N25 N16 Gnd Gnd NMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M6 N36 N25 Gnd Gnd NMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M7 out N36 Gnd Gnd NMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M8 N34 in N49 Gnd NMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M9 N49 out Gnd Gnd NMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M10 N16 N34 Vdd Vdd PMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M11 N25 N16 Vdd Vdd PMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M12 N36 N25 Vdd Vdd PMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M13 out N36 Vdd Vdd PMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24u
M14 N34 N34 Vdd Vdd PMOS L=2u W=22u AD=66p PD=24u AS=66p PS=24uv15
Vdd Gnd 5.0
v16 in Gnd pulse(0.0 5.0 10n 20n 20n 100n 30n)
RESULT OF SIMULATION:-
Department of Electronics and Comm.Enggneering.SDITS, Khandwa Page 3
Manual of Ring Oscillator.
Figure: 4 simulation result of ring oscillator
Department of Electronics and Comm.Enggneering.SDITS, Khandwa Page 4
Manual of Ring Oscillator.
Department of Electronics and Comm.Enggneering.SDITS, Khandwa Page 5
