Connection details
Name
|
Description
|
Flow
|
Type
|
in
|
Input |
in |
d |
out
|
Output |
out |
d |
Model parameters
Name
|
Description
|
Type
|
Default
|
Limits
|
rise_delay
|
Rise delay |
real |
1nS |
1e-12 −∞ |
fall_delay
|
Fall delay |
real |
1nS |
1e-12 −∞ |
stored_delay
|
Stored delay (overrides rise_delay and fall_delay) |
real |
0 |
0−∞ |
input_load
|
Input load value (F) |
real |
1pF |
none |
family
|
Logic family |
string |
UNIV |
none |
in_family
|
Input logic family |
string |
UNIV |
none |
out_family
|
Output logic family |
string |
UNIV |
none |
out_res
|
Digital output resistance |
real |
100 |
0−∞ |
out_res_pos
|
Digital output res. pos. slope |
real |
out_res |
0−∞ |
out_res_neg
|
Digital output res. neg. slope |
|
out_res |
0−∞ |
open_c
|
Open collector output |
boolean |
FALSE |
none |
min_sink
|
Minimum sink current |
real |
-0.001 |
none |
max_source
|
Maximum source current |
real |
0.001 |
none |
sink_current
|
Input sink current |
real |
0 |
none |
source_current
|
Input source current |
real |
0 |
none |
open_e
|
Open emitter output |
boolean |
FALSE |
none |
Device Operation
This device is a simple buffer with a single input and output. It can optionally be specified to have an open collector (open_c parameter) or open emitter (open_e parameter) output. Further, if the stored_delay parameter is specified, the device will act as a pure delay. This means that it will pass pulses that are shorter than the delay time whereas normally (delay specified by rise_delay and fall_delay) such pulse would be swallowed (stored_delay is also known as transport delay).
The following table describes the device operation in detail
OPEN_C
parameter
|
OPEN_E parameter
|
Input
|
Output state
|
Output strength
|
FALSE
|
FALSE |
0 |
0 |
STRONG |
FALSE
|
FALSE |
1 |
1 |
STRONG |
FALSE
|
FALSE |
UNKNOWN |
UNKNOWN |
STRONG |
FALSE
|
TRUE |
0 |
0 |
HI-IMPEDANCE |
FALSE
|
TRUE |
1 |
1 |
STRONG |
FALSE
|
TRUE |
UNKNOWN |
UNKNOWN |
UNDETERMINED |
TRUE
|
FALSE |
0 |
0 |
STRONG |
TRUE
|
FALSE |
1 |
0 |
HI-IMPEDANCE |
TRUE
|
FALSE |
UNKNOWN |
0 |
UNDETERMINED |
TRUE
|
TRUE |
0 |
1 |
HI-IMPEDANCE |
TRUE
|
TRUE |
1 |
0 |
HI-IMPEDANCE |
TRUE
|
TRUE |
UNKNOWN |
UNKNOWN |
UNDETERMINED |
Note the difference between open emitter and open collector operation. These modes have been designed to be as close to as possible to real devices, in particular their behaviour into an open circuit. An open emitter output, when switching from high to low is likely to follow the voltage on the device's base due to the base-emitter capacitance so the output state follows the input state. An open collector (or open drain) output on the other hand will remain in the low state when its input switches.