DELAY Primitive

Path delay element for backannotation.

BACKANNOTATION

Model

I DELAY Q

Description

The DELAY primitive is a backannotation element used to add path delays to a circuit. It represents a point-to-point propagation delay that can be inserted into the signal path during post-layout timing analysis.

Backannotation elements like DELAY and LOAD allow designers to incorporate extracted timing information from layout tools back into the simulation model without modifying the original circuit description.

Equivalent Type Statement

Type=DELAY i=I o=Q

Usage in Network Description

The DELAY element is instantiated in the network description to model path delays:

PART= TYPE=delay I= O= $
    ORISE= OFALL=

Or using the OCHANGE keyword for symmetric delays:

PART= TYPE=delay I= O= $
    OCHANGE=

Usage in Backannotation Files

DELAY elements are commonly used in backannotation (.ann) files that are read with the GET AFILE= command. These files can contain DELAY instances alongside LOAD elements to add both path delays and net loading to the circuit.

Example

Adding a path delay of 5 time units between two circuit nodes:

PART=path_delay1 TYPE=delay I=node_a O=node_b OCHANGE=5

Adding different rise and fall delays:

PART=path_delay2 TYPE=delay I=sig_in O=sig_out $
    ORISE=7 OFALL=5

Notes