Re: problem with a model

Olli,

I have also seen this when generating models for TTL glue logic
when using SPICE2IBIS. I presume this indicates that the
SPICE transistor level model was only designed to work over
a limited range of voltages.

Ian Dodd

"Muranyi, Arpad" wrote:
>
> Olli,
>
> This can happen if the IV curve is made from lab
> measurements and they sweep it to slowly. The chip
> heats up and consequently the current goes down.
>
> Arpad Muranyi
> Intel Corporation
> ====================================================
>
> -----Original Message-----
> From: Olli Timonen [mailto:Olli.Timonen@tellabs.com]
> Sent: Friday, August 11, 2000 2:22 AM
> To: IBIS
> Subject: problem with a model
>
> Hi!
>
> I have a problem with one IBIS model. The current of a pulldown starts
> to decrease after about 5V. How is this possible? What causes this kind
> of occurrences and is there any kind of solutions to fix this kind of a
> model?
>
> The [Pulldown] of a model in question is below.
>
> Regards,
> Olli
>
> |************************************************************************
>
> | Model Buffer
> |************************************************************************
>
> |
> [Model] Buffer
> Model_type 3-state
> Polarity Non-Inverting
> Enable Active-High
> Vinl = 0.00V
> Vinh = 5.00V
> C_comp 5.00pF 5.00pF 5.00pF
> |
> |
> [Temperature Range] 25.00 100.00 -40.00
>
> [Voltage Range] 5.00V 4.50V 5.50V
> [Pulldown]
> | voltage I(typ) I(min) I(max)
> |
> -5.00 -1000.00uA -1000.00uA 0.00A
> -4.60 0.00A 0.00A 0.00A
> -4.20 -1.00mA -1.00mA -1000.00uA
> -3.80 -1.00mA 0.00A -1.00mA
> -3.40 -1.00mA 0.00A -1.00mA
> -3.00 -1000.00uA -1000.00uA -1.00mA
> -2.60 -1000.00uA -1000.00uA -2.00mA
> -2.20 -1.00mA 0.00A -2.00mA
> -1.80 -2.00mA -2.00mA -3.00mA
> -1.40 -3.50mA -2.00mA -5.80mA
> -1.00 -10.70mA -4.60mA -37.60mA
> -0.90 -19.70mA -6.50mA -83.83mA
> -0.80 -43.09mA -10.50mA -93.72mA
> -0.70 -53.81mA -20.14mA -85.15mA
> -0.60 -48.13mA -28.69mA -75.24mA
> -0.50 -41.67mA -26.51mA -65.04mA
> -0.40 -34.83mA -22.15mA -54.70mA
> -0.30 -27.32mA -17.29mA -43.21mA
> -0.20 -19.06mA -12.00mA -30.38mA
> -0.10 -10.00mA -6.25mA -16.04mA
> 0.00 0.00A 0.00A 0.00A
> 0.10 10.61mA 6.62mA 16.95mA
> 0.20 21.06mA 13.28mA 33.15mA
> 0.30 31.04mA 19.69mA 48.53mA
> 0.40 40.58mA 25.83mA 63.11mA
> 0.50 49.67mA 31.71mA 76.92mA
> 0.60 58.31mA 37.32mA 89.97mA
> 0.70 66.54mA 42.66mA 102.32mA
> 0.80 74.33mA 47.74mA 113.91mA
> 0.90 81.73mA 52.57mA 124.89mA
> 1.00 88.71mA 57.14mA 135.18mA
> 1.10 95.29mA 61.45mA 144.77mA
> 1.20 101.53mA 65.51mA 153.85mA
> 1.30 107.31mA 69.32mA 162.24mA
> 1.40 112.70mA 72.88mA 170.12mA
> 1.50 117.78mA 76.19mA 177.41mA
> 1.60 122.47mA 79.26mA 184.09mA
> 1.70 126.85mA 82.09mA 190.38mA
> 1.80 130.83mA 84.68mA 196.06mA
> 1.90 134.52mA 87.04mA 201.25mA
> 2.00 137.90mA 89.16mA 206.03mA
> 2.10 140.89mA 91.06mA 210.31mA
> 2.20 143.57mA 92.73mA 214.20mA
> 2.30 145.95mA 94.18mA 217.58mA
> 2.40 148.04mA 95.40mA 220.56mA
> 2.50 149.82mA 96.42mA 223.14mA
> 2.60 151.30mA 97.23mA 225.32mA
> 2.70 152.48mA 97.82mA 227.11mA
> 2.80 153.47mA 98.21mA 228.59mA
> 2.90 154.15mA 98.50mA 229.67mA
> 3.00 154.53mA 98.79mA 230.45mA
> 3.10 155.01mA 99.06mA 231.03mA
> 3.20 155.29mA 99.28mA 231.51mA
> 3.30 155.68mA 99.57mA 231.99mA
> 3.40 156.06mA 99.85mA 232.46mA
> 3.50 156.34mA 100.04mA 232.84mA
> 3.60 156.62mA 100.23mA 233.32mA
> 3.70 156.90mA 100.41mA 233.70mA
> 3.80 157.18mA 100.60mA 233.98mA
> 3.90 157.46mA 100.79mA 234.35mA
> 4.00 157.64mA 100.97mA 234.63mA
> 4.10 157.92mA 101.16mA 234.91mA
> 4.20 158.11mA 101.35mA 235.09mA
> 4.30 158.29mA 101.43mA 235.36mA
> 4.40 158.47mA 101.62mA 235.54mA
> 4.50 158.55mA 101.70mA 235.71mA
> 4.60 158.73mA 101.79mA 235.79mA
> 4.70 158.81mA 101.88mA 235.87mA
> 4.80 158.89mA 101.96mA 235.94mA
> 4.90 158.97mA 102.08mA 236.02mA
> 5.00 159.05mA 101.98mA 236.09mA
> 5.10 159.03mA 101.88mA 236.07mA
> 5.20 159.01mA 102.00mA 236.04mA
> 5.30 159.09mA 102.10mA 235.91mA
> 5.40 159.04mA 102.20mA 235.89mA
> 5.50 158.73mA 102.10mA 235.76mA
> 5.60 158.13mA 102.20mA 235.64mA
> 5.70 157.92mA 102.20mA 235.41mA
> 5.80 158.36mA 101.80mA 235.28mA
> 5.90 158.40mA 102.00mA 234.97mA
> 6.00 158.40mA 102.00mA 234.25mA
> 6.40 157.60mA 102.00mA 232.97mA
> 6.80 158.00mA 102.00mA 232.20mA
> 7.20 156.00mA 101.00mA 231.00mA
> 7.60 156.00mA 101.00mA 230.00mA
> 8.00 155.00mA 101.00mA 229.00mA
> 8.40 155.00mA 101.00mA 228.00mA
> 8.80 155.00mA 101.00mA 226.00mA
> 9.20 154.00mA 100.00mA 225.00mA
> 9.60 153.00mA 100.00mA 224.00mA
> 10.00 153.00mA 99.00mA 222.00mA
Received on Fri Aug 11 10:43:03 2000