Cadence Mixed-Signal Circuit Design Environment User Guide
Interface Element Macro Models
October 2003
46
Product Version 5.0
The A2D interface primitive senses the voltage at the interface net
&2
and sends the
corresponding logic state to the digital destination. Subcircuit
C&1
is used to characterize the
transistor effects of a TTL input pin. Transistor
Q1
sources a moderate current when the
interface net is low and sinks a small current when the interface net is high.
If you place an A2D primitive statement within a subcircuit, you must set the nesting level
parameter of the A2D primitive to 1 or higher. Set the
NESTLEV
parameter to reflect the
number of subcircuit levels down in the IE macro model file that the A2D primitive is
embedded. See the Spectre IE model
CML_a2d.scs
for an example of a primitive nested in
a subcircuit.
CDF Parameters
For each A2D interface element, the SpectreS netlister maps the CDF parameters to
SpectreS parameters using the cdsSpice simulator information from the CDF.
Note: The SpectreS netlister and the cdsSpice netlister have many attributes in common.
The CDF information for cdsSpice is used for netlisting interface elements for SpectreS
simulation. CDF information for SpectreS simulation is not needed.
Digital
destination
+
net &2
Q1
R1
R3
R2
VDD
X&1
Summary :
Cadence Mixed-Signal Circuit Design Environment User Guide Interface Element Macro Models October 2003 46 Product Version 5.0 The A2D interface primitive senses the voltage at the interface net &2 and sends the corresponding logic state to the digital destination.
Tags :
interface,a2d,primitie,cdf,spectres,subcircuit,net,information,netlister,cdsspice,parameters,transistor,parameter