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  3. Problem with sram read operation pspice netlist

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Problem with sram read operation pspice netlist

rajrevanth61
rajrevanth61 over 11 years ago
Hello Everyone,

I have a problem with the read operation of sram , here is my code. I am trying to read a value of 1 , when i simulate with the following code, both bl and blb are staying high, whereas in the correct operation bl should stay high and blb should go low. Please help me with this. I am in urgent need of this.

*sram*

*source
vdd vdd 0 dc 1

*initial conditions stored for read operation
vq Q 0 dc 1
vqr QR 0 dC 0

*data control
vbl bl 0 pulse(0 0.5 1m 100u 100u 5m 5m)
vblb blb 0 pulse(0 0.5 1m 100u 100u 5m 5m)

*access control
vwl wl 0 pulse(0 2 3m 100u 100u 5m 5m)

*transistors used for latching
m1 QR Q 0 0 NMOS l=0.18u w=0.36u

m2 QR Q vdd vdd PMOS l=0.18u w=0.72u

m3 Q QR 0 0 NMOS l=0.18u w=0.36u

m4 Q QR vdd vdd PMOS l=0.18u w=0.72u


*transistors used for data access
m5 bl wl Q Q NMOS l=0.18u w=0.36u
m6 blb wl QR QR NMOS l=0.18u w=0.36u


.tran 100n 100m

.probe


.MODEL NMOS NMOS
+ LEVEL = 3
+ VTO = 0.41
+ TOX = 2.2E-09
+ NSUB = 2.0E+18
+ NFS = 6.0E+12
+ XJ = 6E-8
+ LD = 9e-9
+ UO = 390
+ VMAX = 2.2E+05
+ THETA = 0.80
+ ETA = 2.8E-03
+ KAPPA = 0.2
+ GAMMA = 0.40
+ RSH = 500
+ CGSO = 3.33449e-10
+ CGDO = 3.33449e-10
+ CGBO = 0.0
+ CJ = 4.96491e-3
+ CJSW = 2.45744e-10


.MODEL PMOS PMOS
+ LEVEL = 3
+ VTO = -0.41
+ TOX = 2.2E-09
+ NSUB = 2.0E+18
+ NFS = 6.0E+12
+ XJ = 6E-8
+ LD = 9e-9
+ UO = 175
+ VMAX = 1.1E+05
+ THETA = 0.80
+ ETA = 2.8E-03
+ KAPPA = 0.2
+ GAMMA = 0.40
+ RSH = 500
+ CGSO = 3.33449e-10
+ CGDO = 3.33449e-10
+ CGBO = 0.0
+ CJ = 4.96491e-3
+ CJSW = 2.45744e-10

.end
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  • oldmouldy
    oldmouldy over 11 years ago

    From the look of this, sources vq and vqr will be "forcing" and the node voltages at Q and QR will therefore be fixed. You probably need to remove vq and vqr sources and add:

    .IC V(Q)=1.0 V(QR)=0

    To get initial conditions that are "forced" at the start of the simulation and then "released"

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