eldo_user

IBIS Models Support in Eldo
Example 3—Package Parasitics Cross Talk
Netlist Explanation
_IO_Trx
+ file="tx_rx.ibs"
+ component="transceiver"
+ package=3
The above lines instantiate an IBIS component. Component instantiation means all the buffers
inside the component as well as coupling between pins can be simulated. The component is
named transceiver and located in the tx_rx.ibs IBIS file. The package parameter in the _IO
element specifies the package modeling type to be used. In our case, package=3 means that the
advanced package model, located in the tx_rx.ibs IBIS file under [Define package model] will
be used.
vp _IO_Trx_5 0 pwl (0 0 1n 0 1.6n 3.3 8n 3.3 8.6n 0)
Instantiates the stimulus vp which is a pulse waveform connected between pin 5 of the IBIS
component and ground. It is important to note that all other component pins exist in the
simulation but left unconnected here. A warning will appear about these unconnected pins.
vcc _IO_TRX_4 0 3.3
.connect _IO_TRX_1_d_drive 0
.connect _IO_TRX_2_d_drive 0
.connect _IO_TRX_3_d_drive 0
.connect _IO_TRX_8 0
Rterm1 _IO_TRX_5_d_receive 0 1e6
Rterm2 _IO_TRX_6_d_receive 0 1e6
Rterm3 _IO_TRX_7_d_receive 0 1e6
The above lines have no impact on the simulation results. They are used to avoid warnings
about nodes that have less than two connections. A voltage source vcc is connected between the
node _IO_TRX_4 and ground. The digital inputs of the output buffers (_IO_TRX_1_d_drive,
_IO_TRX_2_d_drive and _IO_TRX_3_d_drive) are tied to ground using the .connect
statement. Also the node _IO_TRX_8 is connected to ground. Then 1MΩ resistors are
connected between the digital outputs of the input buffers (_IO_TRX_5_d_receive,
_IO_TRX_6_d_receive and _IO_TRX_7_d_receive) and ground.
The next part of the netlist specifies the simulation control directives indicating what type of
simulation Eldo should perform on the circuit.
.tran 1p 14n
Specifies a transient analysis be performed lasting 14ns with a plotting increment of 1ps.
.option step=1p
Imposes a time step of 1ps. This small time step is imposed to capture the ringing that will occur
on pin 6 due to both capacitive and inductive coupling with pin 5.
.plot tran v(_IO_TRX_5) v(_IO_TRX_6)
Eldo® User's Manual, 15.3 795