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Measurement TRAN using former referenced voltages

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dkace

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HSpice: Measurement TRAN using former referenced voltages

I am running a transient simulation where I need to calculate the output (OUT1) between 3 cycles

I am using the following lines:

.MEAS TRAN REF_VDD TRIG V(vdd) AT=1p
.MEAS TRAN REF_VSS TRIG V(vss) AT=1p
.MEASURE TRAN CT3 TRIG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VDD))'
+RISE=3 TARG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VDD))' RISE=6

Can anybody locate my fault? I get the error that it never reaches the trigger value.

Thnaks!
 
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erikl

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.MEASURE TRAN CT3 TRIG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VDD))'
+RISE=3 TARG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VDD))' RISE=6

I get the error that it never reaches the trigger value.
It can't: TRIG & TARG val=0
 

dkace

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It can't: TRIG & TARG val=0
My wrong...

Please replace second REF_VDD with REF_VSS

.MEAS TRAN REF_VDD TRIG V(vdd) AT=1p
.MEAS TRAN REF_VSS TRIG V(vss) AT=1p
.MEASURE TRAN CT3 TRIG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VSS))'
+RISE=3 TARG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VSS))' RISE=6


Still get the same error.

The problem is that the REF_VDD and REF_VSS are calculated in seconds and I need voltage calculated over time.
 

erikl

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.MEASURE TRAN CT3 FROM TRIG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VSS))' RISE=3
+ TO TARG V(OUT1) val='0.5*(V(REF_VDD)-V(REF_VSS))' RISE=6


Still get the same error.

The problem is that the REF_VDD and REF_VSS are calculated in seconds and I need voltage calculated over time.
Try replacing 'TRIG' & 'TARG' by 'FROM' & 'TO' -- or just add these 2 commands (s. above).
 

dkace

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Thanks for the tip.

I finally managed to produce results with the original one without the val

But I will try the FROM ...TO format. It seems more straight forward.

Now, I have a new one: I can't get the positive node of VDD (V_VDD VD 0 DC='vdd') to get recognized from the netlister.

Although I am using exactly the same format for VSS (with VS for the node), for some reason this is omited and I get en error when I am trying to measure current averaged over transient through that node.

Any suggestions ?

- - - Updated - - -

Thanks for the tip.

I finally managed to produce results with the original one without the val

But I will try the FROM ...TO format. It seems more straight forward.

Now, I have a new one: I can't get the positive node of VDD (V_VDD VD 0 DC='vdd') to get recognized from the netlister.

Although I am using exactly the same format for VSS (with VS for the node), for some reason this is omited and I get en error when I am trying to measure current averaged over transient through that node.

Any suggestions ?
 

erikl

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I can't get the positive node of VDD (V_VDD VD 0 DC='vdd') to get recognized from the netlister.

Although I am using exactly the same format for VSS (with VS for the node), for some reason this is omited and I get en error when I am trying to measure current averaged over transient through that node.
May be 'VD' is a reserved command word. Try using a different node name!
 

dkace

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Well, finally I have obtain valid information!
The code is as follows
.MEASURE TRAN REF_VDD AVG V(vdd) FROM=2p TO='t'
.MEASURE TRAN REF_VSS AVG V(vss) FROM=2p TO='t'

.MEASURE TRAN CT3 TRIG V(OUT1)='0.5*(REF_VDD-REF_VSS)' RISE=3
+TARG V(OUT1)='0.5*(REF_VDD-REF_VSS)' RISE=6
.MEASURE T_c PARAM='CT3/3'


The problem was the selection of the setting of the correct nodes and outputs.

I now have another one:

I want to measure current, after transient simulation at 30ns. How do I set up this .MEASUREMENT command?
 

erikl

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Well, finally I have obtain valid information!
The code is as follows
.MEASURE TRAN REF_VDD AVG V(vdd) FROM=2p TO='t'
.MEASURE TRAN REF_VSS AVG V(vss) FROM=2p TO='t'

.MEASURE TRAN CT3 TRIG V(OUT1)='0.5*(REF_VDD-REF_VSS)' RISE=3
+TARG V(OUT1)='0.5*(REF_VDD-REF_VSS)' RISE=6
.MEASURE T_c PARAM='CT3/3'

The problem was the selection of the setting of the correct nodes and outputs.
Thank you for your feedback!

I want to measure current, after transient simulation at 30ns. How do I set up this .MEASUREMENT command?
I can't verify it right now, but I think it should work in analogy to the voltage measurement:

.MEASURE TRAN Iavg AVG I(vdd) FROM=2p TO='t'
 

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