Hi,
Below is the differential ring oscillator .cir file. I am trying to design a ring oscillator with 2GHz oscillating frequency. Output is straight line at around 5V. Is it because I have not given initial condition? If yes, can I please get some help on how to set initial condition? I highly appreciate any help in evaluating the circuit
.MODEL NMOS1 NMOS (VTO=0.70 KP=110U GAMMA=0.4 LAMBDA=0.04 PHI=0.7
+MJ=0.5 MJSW=0.38 CGBO=700P CGSO=220P CGDO=220P CJ=770U CJSW=380P
+LD=0.016U TOX=14N)
*(each differential cell)
.SUBCKT DELAY 1 2 3 4 5 6
R1 5 3 20K
R2 4 5 20K
M1 3 1 6 6 NMOS1 W=3U L=1U
M2 4 2 6 6 NMOS1 W=3U L=1U
.ENDS DELAY
XC 1 2 3 4 5 6 DELAY
XD 4 3 7 8 5 6 DELAY
XE 8 7 1 2 5 6 DELAY
ISS 6 0 20U
VDD 5 0 5
.TRAN 1NS 1500NS
.PROBE
.END
Below is the differential ring oscillator .cir file. I am trying to design a ring oscillator with 2GHz oscillating frequency. Output is straight line at around 5V. Is it because I have not given initial condition? If yes, can I please get some help on how to set initial condition? I highly appreciate any help in evaluating the circuit
.MODEL NMOS1 NMOS (VTO=0.70 KP=110U GAMMA=0.4 LAMBDA=0.04 PHI=0.7
+MJ=0.5 MJSW=0.38 CGBO=700P CGSO=220P CGDO=220P CJ=770U CJSW=380P
+LD=0.016U TOX=14N)
*(each differential cell)
.SUBCKT DELAY 1 2 3 4 5 6
R1 5 3 20K
R2 4 5 20K
M1 3 1 6 6 NMOS1 W=3U L=1U
M2 4 2 6 6 NMOS1 W=3U L=1U
.ENDS DELAY
XC 1 2 3 4 5 6 DELAY
XD 4 3 7 8 5 6 DELAY
XE 8 7 1 2 5 6 DELAY
ISS 6 0 20U
VDD 5 0 5
.TRAN 1NS 1500NS
.PROBE
.END