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dear all,
anyone of you have designed 3- or 4-wire dc motor driver b4? i wonder how you model the motor with TACh output and PWM input? any spice model?
Thanks and regards,
smart
hi anachip,
if you r using spectre, you can use the XF analysis, it allow you to small signal analysis from different input sources which with respect to your output.
After run, go to direct plot, and check the XF result.
hope this help
cadence stb
For multi-loop stability analysis, you should check the inner loop first and the outer loop check later.
so in your case you should make sure the CMFB has enough of phase margin, then proceed to the RC feedback path.
Hope this helps
Regards,
Smart
Re: What's the operating Points regions stand for? (in Spect
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HI ,
In spectre, the operating region is :
0 -> Cut-off
1 -> Linear
2 -> Saturation
3 -> Weak inverstion
4 -> Break down
hope this help...
Re: corners
Jutek,
To me, the output variation is normal (with the corner), the overall variation in waveform shows only about 10mV (0.798~ 0.808v) across the process.
You may check if all the MOS in your design is in satuation or not? How much the loop gain variation across corner...
Re: corners
Hi Jutek,
Pls label the signal.
One thing i can see from the waveform is that the phase margin is not well compensated yet.
Another thing is : why you call it corner? corner supposed to be simulated accoss all the PVT. or you meant something else?
regards,
smart
Re: corners
hi jutek,
ok, let's stick with the case when vdd=1.3v.
so in this case the vout = 0.8v, RL=8, so the driving current is 100mA,right? I think it just make sense to me, it need such a big size to current for so much current. Otherwise, if you decrease the size, the pass transistor...
Re: corners
Hi Jutek,
the process compesation technique is application depandent.
For an simple example: A voltage regulator which can regulate the stable output voltage at all corner.
you can probably post your circuit, without knowing it, it's hard help you.
regards,
smart
Re: corners
I think it's possible.
just for your reference: the IBM 0.18um that i'm currently, PMOS's vth variation is about 200mv.
you may use feedback circuit to compensate the process variation.
regards,
smart
Re: Why does the ac curve of this OPA has no -3dB breakoff p
Dear huojinsi,
I have few comments here:
1. Are you sure your MOS size is correct? should it in micro meter range? please check and confirm with us
2. Can you please change your Capacitor value C1=1GF and instead of putting the...
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