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I noticed that MODELZEN connects the body terminals of all transistors to a ground node (`ground). Isn't that an error?
Here is a CMOS inverter circuit as an example. Note that its pMOS transistor has its body terminal connected to the power supply (vdd) and its nMOS transistor has its body terminal connected to the ground.
But in the SystemVerilog model extracted by MODELZEN, the 'b' terminals of both the nmosfet and pmosfet primitives are connected to the ground (`ground).
Your observation is correct, but this is not an error at the moment. Since the nmosfet and pmosfet primitives of XMODEL do not currently model any body-dependent effects, their body terminal voltages do not have any effects on the transistor characteristics. This is why MODELZEN blindly connects all the body terminals to `ground.
When the nmosfet and pmosfet primitives are extended to include those body-dependent effects, MODELZEN will start to reflect the actual signals connected to the body terminals in the generated models. For your information, the body-dependent effects are relatively weak in deeply-scaled transistors.
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MODELZEN으로 모델을 추출하면 모든 트랜지스터의 바디(body) 또는 벌크(bulk) 단자가 모두 0V 그라운드 노드(`ground)로 연결되는 것을 보았습니다. 이것은 오류가 아닌지요?
아래는 CMOS 인버터 회로의 예입니다. PMOS 트랜지스터는 바디 단자가 전원 전압인 vdd에 연결되어 있고, NMOS 트랜지스터는 바디 단자가 그라운드로 연결되어 있습니다.
그런데, MODELZEN이 이 회로로부터 추출한 SystemVerilog 모델을 살펴보면, nmosfet과 pmosfet primitive 모두 'b' 단자가 그라운드, 즉 `ground로 연결되어 있는 것을 확인할 수 있습니다.
Your observation is correct, but this is not an error at the moment. Since the nmosfet and pmosfet primitives of XMODEL do not currently model any body-dependent effects, their body terminal voltages do not have any effects on the transistor characteristics. This is why MODELZEN blindly connects all the body terminals to `ground.
When the nmosfet and pmosfet primitives are extended to include those body-dependent effects, MODELZEN will start to reflect the actual signals connected to the body terminals in the generated models. For your information, the body-dependent effects are relatively weak in deeply-scaled transistors.
Please login or Register to submit your answer