Re: Spice model 4069UB

"Malcolm Reeves" <mreeves@xxxxxxxxxxxxxxx> schrieb im Newsbeitrag
news:tvutb1dsoigdg9ieimne3lku5c0547ltjo@xxxxxxxxxx
> On Sun, 26 Jun 2005 10:53:29 -0700, Jim Thompson
> <thegreatone@xxxxxxxxxxx> wrote:
>
>>On Sun, 26 Jun 2005 18:30:12 +0100, Malcolm Reeves
>><mreeves@xxxxxxxxxxxxxxx> wrote:
>>
>>>Hi,
>>>
>>>I'm still not happy with my spice models. I ask this before and was
>>>given this:
>>>
>>>* CD4069UB CMOS HEX INVERTER as amplifier
>>>*connections A(in) G(out) VDD VSS
>>>.subckt 4069UB 6 1 4 10
>>>M2 1 6 10 10 CD4069BN
>>>M3 1 6 4 4 CD4069BP
>>>.MODEL CD4069BN NMOS (LEVEL=1 VTO=2.1 KP=2.9M GAMMA=3.97U
>>>+ PHI=.75 LAMBDA=1.87M RD=20.2 RS=184.1 IS=31.2F PB=.8 MJ=.46
>>>+ CBD=47.6P CBS=57.2P CGSO=70.2N CGDO=58.5N CGBO=96.3N)
>>>.MODEL CD4069BP PMOS (LEVEL=1 VTO=-2.9 KP=2M GAMMA=3.97U
>>>+ PHI=.75 LAMBDA=1.87M RD=28.2 RS=145.2 IS=31.2F PB=.8 MJ=.46
>>>+ CBD=47.6P CBS=57.2P CGSO=70.2N CGDO=58.5N CGBO=96.3N)
>>>.ENDS 4069UB
>>>*$
>>>
>>>I've tried this on ac analysis, that from the output 1F/1G filter,
>>>gain of 1 buffer, 1VAC source. The ac source scans the frequency
>>>response and the rest set the dc level. At 5V the above circuit has
>>>next to no gain. At 15V the gain is 350 up to 10kHz then rolls off.
>>>At 5V supply the gain is rolling off at 10Hz. The model is just not
>>>accurate.
>>>
>>>Jim has sent me his HCU04 model but I'm actually using a 4069 since in
>>>practice I can't see an circuit differences except the 4069 takes less
>>>current. That has a flat gain of 12 which also isn't right. There is
>>>still quite some gain at 100kHz.
>>>
>>>Anyone have a better model or can tell me what of the multitude of
>>>params I should vary to get the model right?
>>>
>>>TIA
>>
>>Malcolm, How are you setting up the bias to put the inverter in the
>>"linear" region?
>
> The output of the inverter feeds a 1g/1F RC i.e. the RC only pass dc.
> E source buffers this. Next is series 1VAC source which feeds back to
> the input. Hence input is 1VAC on top of dc from output. Bias then
> finds its own level. Analysis is ac of course, so small signal.
>
> BTW input (and output) bias points on 5V supply is 2.1V for 4069UB
> model, 2.383V for your HCU04 model. For 4069UB on 15V rail bias
> settles to 7.040V.
>
>
> --
>
> Malcolm


Hello Malcolm,

The threshhold votages of both transistors are too high.
The drain currents are in the pA range. I am sure the used
VTO in the models are fallen from the sky but not from real
measurements. :)

Best regards,
Helmut


SPICE output from additional .OP in LTspice:
--------------------------------------------

Direct Newton iteration for .op point succeeded.
Semiconductor Device Operating Points:
--- MOSFET Transistors ---
Name: m:u1:3 m:u1:2
Model: u1:cd4069bp u1:cd4069bn
Id: -2.93e-12 3.75e-12
Vgs: -2.90e+00 2.10e+00
Vds: -2.90e+00 2.10e+00
Vbs: 0.00e+00 0.00e+00
Vth: -2.90e+00 2.10e+00
Vdsat: 0.00e+00 3.34e-05
Gm: 0.00e+00 9.71e-08
Gds: 0.00e+00 3.02e-15
Gmb: 0.00e+00 2.23e-13
Cbd: 2.35e-11 2.63e-11
Cbs: 5.72e-11 5.72e-11
Cgsov: 7.02e-12 7.02e-12
Cgdov: 5.85e-12 5.85e-12
Cgbov: 9.63e-12 9.63e-12
Cgs: 0.00e+00 0.00e+00
Cbd: 0.00e+00 0.00e+00
Cgb: 0.00e+00 0.00e+00


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