Re: [SI-LIST] : IBIS simulation of ZBT SRAM

Arrigo Benedetti (arrigo@vision.caltech.edu)
04 Oct 1999 15:22:50 -0700

"D. C. Sessions" <dc.sessions@vlsi.com> writes:

> Arrigo Benedetti wrote:
> >
> > Dear SI experts,
> >
> > I'd like to know if any of you had better luck in doing signal
> > integrity simulations with ZBT SRAMs. I am simulating a
> > bidirectional data bus between a ZBT and a Xilinx Virtex device. What
> > is strange is that the rise time of the ZBT driver is slow
> > compared to the clock period even for model files of devices in the
> > 166-200 MHz clock frequency range. I tried IBIS files from Micron, IDT
> > and Cypress and the 10-90% rise time is always in the 1.1-2.4 ns. One
> > of these models is so slow that at 166 MHz the voltage on the line
> > does not even reach VDD.
>
> What are the fixture values in the [Rising Waveform] and
> [Falling Waveform] sections? Ludicrously long edge times
> are usually a consequence of traditional (don't get me
> started) capacitive characterization loads.
>
> If you could post the V/T sections it might be even better.
>
> --
> D. C. Sessions
> dc.sessions@vlsi.com
>

The rising and falling waveforms data appear to be missing when I open the
file under Hyperlynx visual IBIS editor. Anyway I took the liberty to
appended the file since it is not very large.
Someone (I am not reporting his name since he sent me a provate email)
reported that the reason why I get these long rise times is that they
are measured using a non-typical load. In fact, when I did a simulation
against the "3.3V I/O output load equivalent circuit" reported in the
Micron data sheet (output pin driving a 50 ohm transmission line terminated
to 1.5V through a 50 Ohm at the other end) and I measure the rise time from
a 1.5V reference, I get 1ns, which is the rise time reported by Micron.
With a series termination driving a transmission line the 10-90% rise time
doubles. Maybe this is not so bad after all and I'm just paranoid...

Best,

-Arrigo

--
Dr. Arrigo Benedetti                e-mail: arrigo@vision.caltech.edu
Caltech, MS 136-93	  			phone: (626) 395-3695
Pasadena, CA 91125	  			fax:   (626) 795-8649

|******************************************************************************* | * mt55l128l36p.ibs * IBIS 2.1 Model for ZBT SRAM * |******************************************************************************* | [IBIS Ver] 2.1 [Comment char] |_char [File name] mt55l128l36p.ibs [Date] Aug 24th, 1999 [File Rev] 2.0 [Source] Micron Technology, Inc. [Notes] 3.3V IO [Disclaimer] THESE DESIGNS ARE PROVIDED "AS IS" WITH NO WARRANTY | WHATSOEVER AND MICRON SPECIFICALLY DISCLAIMS ANY | IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR | A PARTICULAR PURPOSE, OR AGAINST INFRINGEMENT. | |******************************************************************************* | COMPONENT: MT55L128L36P_ZBT_SRAM |******************************************************************************* | [Component] MT55L128L36P_ZBT_SRAM [Manufacturer] Micron Technology, Inc. [Package] |variable typ min max R_pkg 41m 31m 53m L_pkg 3.878n 3.050n 4.870n C_pkg 0.68p 0.57p 0.85p | |******************************************************************************* | [Pin] signal_name model_name 1 DQc D_Q 2 DQc D_Q 3 DQc D_Q 4 VddQ POWER 5 Vss GND 6 DQc D_Q 7 DQc D_Q 8 DQc D_Q 9 DQc D_Q 10 Vss GND 11 VddQ POWER 12 DQc D_Q 13 DQc D_Q 14 Vdd POWER 15 Vdd POWER 16 Vdd POWER 17 Vss GND 18 DQd D_Q 19 DQd D_Q 20 VddQ POWER 21 Vss GND 22 DQd D_Q 23 DQd D_Q 24 DQd D_Q 25 DQd D_Q 26 Vss GND 27 VddQ POWER 28 DQd D_Q 29 DQd D_Q 30 DQd D_Q 31 MODE INP 32 SA INP 33 SA INP 34 SA INP 35 SA INP 36 SA1 INP 37 SA0 INP 38 DNU NC 39 DNU NC 40 Vss GND 41 Vdd POWER 42 DNU NC 43 DNU NC 44 SA INP 45 SA INP 46 SA INP 47 SA INP 48 SA INP 49 SA INP 50 SA INP 51 DQa D_Q 52 DQa D_Q 53 DQa D_Q 54 VddQ POWER 55 Vss GND 56 DQa D_Q 57 DQa D_Q 58 DQa D_Q 59 DQa D_Q 60 Vss GND 61 VddQ POWER 62 DQa D_Q 63 DQa D_Q 64 ZZ INP 65 Vdd POWER 66 Vdd POWER 67 Vss GND 68 DQb D_Q 69 DQb D_Q 70 VddQ POWER 71 Vss GND 72 DQb D_Q 73 DQb D_Q 74 DQb D_Q 75 DQb D_Q 76 Vss GND 77 VddQ POWER 78 DQb D_Q 79 DQb D_Q 80 DQb D_Q 81 SA INP 82 SA INP 83 NC NC 84 NC NC 85 ADV/LD# INP 86 OE# INP 87 CKE# INP 88 R/W# INP 89 CLK INP 90 Vss GND 91 Vdd POWER 92 CE2# INP 93 BWa# INP 94 BWb# INP 95 BWc# INP 96 BWd# INP 97 CE2 INP 98 CE# INP 99 SA INP 100 SA INP | |******************************************************************************* | MODEL D_Q |******************************************************************************* | [Model] D_Q Model_type I/O | | typ min max C_comp 3.09p 2.83p 4.10p Vinl = 0.8 Vinh = 2.0 Rref = 50 Vref = 1.5 | |******************************************************************************* | [Temperature Range] 25 70 0 | [Voltage Range] 3.300 3.135 3.600 | |******************************************************************************* | [Pullup] | Vtable I(typ) I(min) I(max) | -3.300 252.696m 252.653m 252.721m -3.200 252.711m 252.692m 252.740m -3.100 252.718m 252.708m 252.710m -3.000 252.706m 252.693m 252.725m -2.900 252.719m 252.688m 252.724m -2.800 252.705m 252.698m 252.723m -2.700 252.715m 252.678m 252.714m -2.600 252.730m 252.661m 252.723m -2.500 252.720m 252.690m 252.699m -2.400 252.686m 252.683m 252.713m -2.300 252.707m 252.701m 252.690m -2.200 252.679m 252.694m 252.716m -2.100 252.723m 252.700m 252.717m -2.000 252.724m 252.699m 252.694m -1.900 252.795m 252.799m 252.748m -1.800 252.891m 252.888m 252.880m -1.700 252.673m 249.097m 252.816m -1.600 222.895m 219.491m 225.173m -1.500 191.655m 190.320m 192.304m -1.400 161.300m 162.258m 160.719m -1.300 131.949m 135.280m 130.475m -1.200 104.438m 109.369m 101.308m -1.100 78.062m 85.141m 75.008m -1.000 56.128m 62.221m 55.831m -0.900 43.260m 43.978m 45.869m -0.800 36.701m 33.990m 39.839m -0.700 31.540m 28.431m 34.418m -0.600 26.730m 23.834m 29.305m -0.500 22.014m 19.589m 24.264m -0.400 17.481m 15.481m 19.303m -0.300 12.979m 11.468m 14.373m -0.200 8.575m 7.545m 9.440m -0.100 4.255m 3.705m 4.669m -0.000 0.010m 0.033m -0.024m 0.100 -4.062m -3.556m -4.621m 0.200 -8.066m -6.994m -9.069m 0.300 -11.858m -10.289m -13.335m 0.400 -15.528m -13.473m -17.545m 0.500 -19.025m -16.480m -21.496m 0.600 -22.296m -19.340m -25.291m 0.700 -25.356m -22.023m -28.845m 0.800 -28.259m -24.526m -32.225m 0.900 -30.916m -26.863m -35.349m 1.000 -33.386m -28.980m -38.265m 1.100 -35.620m -30.923m -40.985m 1.200 -37.661m -32.677m -43.449m 1.300 -39.488m -34.219m -45.698m 1.400 -41.121m -35.659m -47.731m 1.500 -42.559m -36.855m -49.569m 1.600 -43.812m -37.941m -51.208m 1.700 -44.921m -38.893m -52.613m 1.800 -45.899m -39.691m -53.909m 1.900 -46.721m -40.418m -55.071m 2.000 -47.440m -40.998m -56.054m 2.100 -48.076m -41.551m -56.921m 2.200 -48.641m -42.041m -57.704m 2.300 -49.160m -42.466m -58.393m 2.400 -49.619m -42.879m -58.983m 2.500 -50.056m -43.210m -59.570m 2.600 -50.416m -43.578m -60.078m 2.700 -50.776m -43.893m -60.533m 2.800 -51.105m -44.173m -60.921m 2.900 -51.419m -44.449m -61.315m 3.000 -51.679m -44.728m -61.670m 3.100 -51.976m -44.949m -61.950m 3.200 -52.225m -45.184m -62.291m 3.300 -52.479m -45.421m -62.608m 3.400 -52.716m -45.625m -62.866m 3.500 -52.934m -45.884m -63.126m 3.600 -53.162m -46.190m -63.397m 3.700 -53.379m -47.523m -63.666m 3.800 -53.646m -52.646m -63.891m 3.900 -54.791m -118.489m -64.100m 4.000 -58.750m -194.450m -64.314m 4.100 -166.570m -256.686m -64.537m 4.200 -241.481m -259.123m -65.328m 4.300 -259.265m -258.436m -68.414m 4.400 -258.464m -258.414m -76.525m 4.500 -258.461m -258.409m -258.705m 4.600 -258.442m -258.403m -258.469m 4.700 -258.451m -258.380m -258.406m 4.800 -258.442m -258.368m -258.418m 4.900 -258.429m -258.403m -258.415m 5.000 -258.460m -258.385m -258.419m 5.100 -258.431m -258.374m -258.419m 5.200 -258.461m -258.387m -258.425m 5.300 -258.417m -258.388m -258.438m 5.400 -258.411m -258.386m -258.436m 5.500 -258.429m -258.384m -258.430m 5.600 -258.442m -258.379m -258.410m 5.700 -258.433m -258.409m -258.405m 5.800 -258.434m -258.366m -258.428m 5.900 -258.430m -258.359m -258.434m 6.000 -258.439m -258.370m -258.421m 6.100 -258.421m -258.388m -258.425m 6.200 -258.436m -258.364m -258.445m 6.300 -258.436m -258.380m -258.399m 6.400 -258.449m -258.373m -258.379m 6.500 -258.429m -258.381m -258.410m 6.600 -258.412m -258.358m -258.399m | [Pulldown] | Vout I(typ) I(min) I(max) | 6.600 252.73m 252.70m 252.72m 6.500 252.69m 252.67m 252.72m 6.400 252.65m 252.66m 252.72m 6.300 252.74m 252.69m 252.68m 6.200 252.72m 252.70m 252.73m 6.100 252.74m 252.66m 252.67m 6.000 252.66m 252.69m 252.70m 5.900 252.67m 252.70m 252.68m 5.800 252.70m 252.66m 252.68m 5.700 252.73m 252.74m 252.69m 5.600 252.67m 252.69m 252.68m 5.500 252.75m 252.69m 252.71m 5.400 252.67m 252.66m 252.70m 5.300 252.74m 252.68m 252.67m 5.200 252.74m 252.67m 252.68m 5.100 252.72m 252.65m 252.84m 5.000 252.73m 252.69m 227.54m 4.900 252.89m 252.69m 196.04m 4.800 249.67m 252.68m 166.19m 4.700 218.31m 252.84m 137.59m 4.600 188.38m 231.53m 110.42m 4.500 159.75m 203.11m 90.87m 4.400 132.77m 175.62m 84.29m 4.300 106.46m 149.63m 82.84m 4.200 84.21m 124.89m 82.34m 4.100 73.61m 101.37m 82.10m 4.000 71.23m 79.64m 81.93m 3.900 70.59m 66.15m 81.76m 3.800 70.40m 62.08m 81.69m 3.700 70.35m 61.13m 81.60m 3.600 70.23m 60.90m 81.57m 3.500 70.11m 60.80m 81.54m 3.400 70.05m 60.74m 81.48m 3.300 69.98m 60.66m 81.35m 3.200 69.90m 60.58m 81.35m 3.100 69.83m 60.49m 81.27m 3.000 69.82m 60.44m 81.23m 2.900 69.73m 60.38m 81.10m 2.800 69.65m 60.28m 81.06m 2.700 69.53m 60.19m 80.91m 2.600 69.44m 60.08m 80.79m 2.500 69.29m 59.95m 80.61m 2.400 69.11m 59.84m 80.44m 2.300 68.97m 59.68m 80.21m 2.200 68.76m 59.49m 79.93m 2.100 68.50m 59.28m 79.50m 2.000 68.20m 59.00m 79.05m 1.900 67.79m 58.67m 78.42m 1.800 67.25m 58.26m 77.65m 1.700 66.55m 57.70m 76.60m 1.600 65.68m 56.98m 75.30m 1.500 64.54m 56.06m 73.69m 1.400 63.10m 54.85m 71.73m 1.300 61.30m 53.37m 69.35m 1.200 59.10m 51.51m 66.57m 1.100 56.48m 49.28m 63.31m 1.000 53.39m 46.66m 59.56m 0.900 49.84m 43.58m 55.35m 0.800 45.81m 40.11m 50.66m 0.700 41.29m 36.24m 45.50m 0.600 36.37m 31.94m 39.90m 0.500 30.98m 27.28m 33.87m 0.400 25.26m 22.26m 27.51m 0.300 19.22m 16.96m 20.88m 0.200 12.91m 11.39m 13.96m 0.100 6.41m 5.63m 6.92m 0.000 -0.27m -0.28m -0.31m -0.100 -7.05m -6.32m -7.61m -0.200 -13.87m -12.42m -14.92m -0.300 -20.71m -18.57m -22.26m -0.400 -27.53m -24.69m -29.53m -0.500 -34.29m -30.87m -36.76m -0.600 -41.23m -37.57m -44.03m -0.700 -49.12m -46.80m -52.05m -0.800 -61.14m -139.83m -62.04m -0.900 -241.30m -209.99m -258.61m -1.000 -259.31m -259.63m -258.43m -1.100 -258.46m -258.84m -258.42m -1.200 -258.44m -258.37m -258.40m -1.300 -258.43m -258.37m -258.40m -1.400 -258.42m -258.36m -258.41m -1.500 -258.42m -258.37m -258.43m -1.600 -258.41m -258.38m -258.41m -1.700 -258.39m -258.35m -258.41m -1.800 -258.40m -258.34m -258.41m -1.900 -258.41m -258.35m -258.36m -2.000 -258.42m -258.35m -258.37m -2.100 -258.42m -258.36m -258.35m -2.200 -258.41m -258.35m -258.37m -2.300 -258.41m -258.31m -258.38m -2.400 -258.37m -258.33m -258.34m -2.500 -258.41m -258.32m -258.37m -2.600 -258.39m -258.31m -258.35m -2.700 -258.36m -258.33m -258.37m -2.800 -258.40m -258.34m -258.38m -2.900 -258.39m -258.29m -258.40m -3.000 -258.39m -258.32m -258.34m -3.100 -258.35m -258.32m -258.36m -3.200 -258.37m -258.31m -258.35m -3.300 -258.40m -258.32m -258.34m | [GND_clamp] | Voltage I(typ) I(min) I(max) | 0.000 0.01m 0.02m 0.01m -0.100 0.02m 0.02m 0.01m -0.200 0.01m 0.01m 0.01m -0.300 0.02m 0.01m 0.02m -0.400 -0.01m -0.02m 0.02m -0.500 -0.12m -0.40m -0.06m -0.600 -1.46m -2.76m -1.02m -0.700 -6.00m -14.26m -4.85m -0.800 -154.46m -128.16m -259.19m -0.900 -220.26m -193.60m -259.10m -1.000 -259.55m -254.21m -258.35m -1.100 -258.64m -259.09m -258.36m -1.200 -258.41m -258.36m -258.35m -1.300 -258.40m -258.36m -258.37m -1.400 -258.40m -258.35m -258.35m -1.500 -258.35m -258.35m -258.36m -1.600 -258.38m -258.36m -258.32m -1.700 -258.38m -258.30m -258.34m -1.800 -258.37m -258.30m -258.34m -1.900 -258.40m -258.33m -258.34m -2.000 -258.41m -258.34m -258.34m -2.100 -258.41m -258.32m -258.35m -2.200 -258.35m -258.32m -258.30m -2.300 -258.37m -258.28m -258.31m -2.400 -258.37m -258.31m -258.32m -2.500 -258.37m -258.31m -258.33m -2.600 -258.37m -258.31m -258.32m -2.700 -258.39m -258.33m -258.32m -2.800 -258.37m -258.31m -258.33m -2.900 -258.34m -258.30m -258.31m -3.000 -258.35m -258.32m -258.34m -3.100 -258.36m -258.27m -258.31m -3.200 -258.36m -258.31m -258.28m -3.300 -258.38m -258.32m -258.34m | [POWER_clamp] | Voltage I(typ) I(min) I(max) | -3.30 252.68m 252.69m 252.71m -3.20 252.69m 252.67m 252.70m -3.10 252.67m 252.68m 252.71m -3.00 252.69m 252.66m 252.70m -2.90 252.72m 252.69m 252.71m -2.80 252.70m 252.65m 252.70m -2.70 252.70m 252.67m 252.71m -2.60 252.73m 252.69m 252.69m -2.50 252.69m 252.70m 252.68m -2.40 252.68m 252.67m 252.66m -2.30 252.69m 252.69m 252.68m -2.20 252.70m 252.69m 252.67m -2.10 252.67m 252.69m 252.65m -2.00 252.69m 252.71m 252.72m -1.90 252.76m 252.85m 252.74m -1.80 252.88m 252.87m 252.87m -1.70 252.23m 237.20m 252.71m -1.60 220.02m 207.05m 221.48m -1.50 188.10m 177.58m 187.86m -1.40 156.72m 148.84m 155.21m -1.30 126.35m 121.17m 123.76m -1.20 97.34m 94.75m 93.52m -1.10 69.96m 69.63m 64.60m -1.00 43.17m 45.68m 36.33m -0.90 19.01m 23.09m 13.02m -0.80 4.43m 6.93m 2.56m -0.70 0.93m 1.44m 0.55m -0.60 0.17m 0.30m 0.10m -0.50 0.03m 0.04m 0.03m -0.40 0.01m 0.02m 0.02m -0.30 0.00m 0.00m 0.00m -0.20 0.00m 0.00m 0.00m -0.10 0.00m 0.00m 0.00m 0.00 0.00m 0.00m 0.00m | [Ramp] |variable typ min max | dV/dt_r 1.43/376p 1.60/392p 1.33/400p dV/dt_f 1.43/392p 1.60/396p 1.33/428p | | Scope: Tek 794D Probe: 450 Ohm Passive | T E S T C I R C U I T | +------+ | | | ___________________ 50 Ohm | | DQ12-+<----()__________________)------\/\/\/\-----< Vt = 1.5V | | | 3" 50 Ohm ^ Termination | | S73A | Transmission Line | | | | | | +------+ | | | | +---/ 450 Ohm \--<50 Ohm | +---\ Passive Probe/--<Scope Input | |******************************************************************************* | MODEL INP |******************************************************************************* | [Model] INP Model_type Input | | typ min max C_comp 1.00p 0.93p 1.52p Vinl = 0.8 Vinh = 2.0 | |******************************************************************************* | [Temperature Range] 25 70 0 | [Voltage range] 3.300 3.135 3.600 | | [GND_clamp] | Voltage I(typ) I(min) I(max) | 0.000 0.01m 0.01m 0.01m -0.100 0.02m 0.02m 0.01m -0.200 0.02m 0.01m 0.02m -0.300 0.02m 0.01m 0.03m -0.400 0.01m -0.02m 0.02m -0.500 -0.11m -0.36m -0.05m -0.600 -1.14m -2.12m -0.81m -0.700 -4.28m -10.65m -3.46m -0.800 -87.01m -77.48m -155.61m -0.900 -134.65m -122.18m -193.69m -1.000 -178.93m -164.46m -232.36m -1.100 -221.24m -204.55m -259.61m -1.200 -259.69m -244.38m -259.12m -1.300 -259.24m -259.50m -258.37m -1.400 -258.44m -258.96m -258.36m -1.500 -258.33m -258.36m -258.35m -1.600 -258.37m -258.31m -258.29m -1.700 -258.36m -258.30m -258.32m -1.800 -258.38m -258.33m -258.34m -1.900 -258.36m -258.33m -258.33m -2.000 -258.32m -258.32m -258.34m -2.100 -258.33m -258.33m -258.31m -2.200 -258.36m -258.29m -258.35m -2.300 -258.35m -258.29m -258.35m -2.400 -258.36m -258.31m -258.34m -2.500 -258.32m -258.33m -258.34m -2.600 -258.36m -258.33m -258.34m -2.700 -258.38m -258.33m -258.34m -2.800 -258.36m -258.26m -258.37m -2.900 -258.34m -258.30m -258.35m -3.000 -258.36m -258.32m -258.35m -3.100 -258.32m -258.30m -258.29m -3.200 -258.32m -258.30m -258.32m -3.300 -258.35m -258.32m -258.34m | [POWER_clamp] | Voltage I(typ) I(min) I(max) | -3.30 252.70m 252.63m 252.70m -3.20 252.68m 252.65m 252.62m -3.10 252.68m 252.69m 252.69m -3.00 252.68m 252.67m 252.70m -2.90 252.67m 252.68m 252.62m -2.80 252.71m 252.67m 252.69m -2.70 252.69m 252.65m 252.62m -2.60 252.71m 252.65m 252.69m -2.50 252.67m 252.66m 252.64m -2.40 252.68m 252.69m 252.66m -2.30 252.70m 252.70m 252.70m -2.20 252.67m 252.68m 252.65m -2.10 252.66m 252.66m 252.62m -2.00 252.65m 252.67m 252.66m -1.90 252.69m 252.69m 252.74m -1.80 252.70m 252.72m 252.68m -1.70 252.68m 252.69m 252.62m -1.60 252.68m 252.67m 252.69m -1.50 252.66m 252.67m 252.62m -1.40 252.67m 252.65m 252.62m -1.30 252.63m 252.70m 252.62m -1.20 252.70m 252.64m 252.65m -1.10 59.72m 252.62m 53.78m -1.00 32.12m 35.77m 26.74m -0.90 10.82m 14.32m 6.82m -0.80 1.05m 2.33m 0.34m -0.70 0.06m 0.15m 0.04m -0.60 0.03m 0.03m 0.04m -0.50 0.02m 0.02m 0.03m -0.40 0.00m 0.02m 0.03m -0.30 0.00m 0.00m 0.00m -0.20 0.00m 0.00m 0.00m -0.10 0.00m 0.00m 0.00m 0.00 0.00m 0.00m 0.00m | [End]

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