analog/digital input/output pad simulation in hspice

[ssahar]

hi

i have several questions about pin and pad modelling:

1. what's difference between analog and digital pads?
2. power supply and GND pads are different from analog pads?
3. how can i model digital/analog/power supply pads in hspice?

is there anybody to help me?
thank you

 

[adix]

1. Digital pads have digital buffers (inverters) to interface the off-chip electronics with the core. No analog signals can thus pass through a digital buffer
2. Power supply pads have ESD protection circuitry and must allow the flow of large currents. They are usually bigger in size
3. Usually the I/O library provided with your technology has the circuit schematic of the pad. You can use that in your simulation