If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

# SN74LVC1G123: No simulation model for this chip after 4 years for tina ti

Part Number: SN74LVC1G123
Other Parts Discussed in Thread: TINA-TI

No simulation model for this chip after 4 years for tina ti

• Hi Rangel,

I understand that it might be frustrating, but the reasons we didn't have one then is the same reasons we don't have one now.

They are explained in [FAQ] Why is there no PSpice model for a Monostable Multivibrator device?

Regards,

Owen

• Hi Rangel,

Generally speaking, I would recommend to just hard-code the pulse for your simulations. To determine pulse width and other behavior of the real device, I recommend building a prototype using our EVMs and sample devices.

-

Generating a pulse in SPICE can be done many ways -- getting an accurate monostable multivibrator circuit is very difficult, but I can help you with a pulse generator circuit pretty easily.

My circuit just watches the input for a high state, then delays that in a second signal and combines the two with some logic (one inverted input AND gate) resulting in a pulse equal to the delay.

Here's the SPICE code:

```* Pulse generator using RC delay element
.SUBCKT PULSE_GEN IN OUT VCC VEE
* Pulse width value is in nanoseconds
+ PARAMS:
+ PULSENS 100

* Threshold is set to VCC/2
EINBUF INBUF VEE VALUE = {IF(V(IN,VEE)>V(VCC,VEE)/2,1,0)}

* Threshold value for timer circuit (1 time constant)
VTHR VTH VEE     0.632119

* R*C provides delay for pulse generator
R1  INBUF TIMER {PULSENS}
C1  TIMER VEE   1E-9

* Delayed output from the timer
EDELAY DELAY VEE VALUE = {IF(V(TIMER,VEE)>V(VTH,VEE),1,0)}

* To get the delay, I multiply the input state (0 or 1) by the
* inverted delayed signal state (0 or 1) to get a short pulse
ELOGIC  LOGIC VEE VALUE = {V(INBUF,VEE) * (1-V(DELAY,VEE))}

* I then use the VCC/VEE connections to determine the output voltage for the pulse:
EOUT OUT VEE VALUE = {V(VCC,VEE) * V(LOGIC,VEE)}
.ENDS
*\$
```

And my Tina-TI example file:

Pulse_Gen_Example.TSC

• Thanks Emrys, solved it for me.