tp3401 National Semiconductor Corporation, tp3401 Datasheet - Page 14

• Manufacturer Part Number: tp3401
• Description: Dasl Digital Adapter For Subscriber Loops
• Manufacturer: National Semiconductor Corporation

Definitions and Timing Conventions
DEFINITIONS
V
V
V
V
Threshold Region
Valid Signal
Invalid Signal
TIMING CONVENTIONS
For the purpose of this timing specification the following
conventions apply
Input Signals
Period
IH
IL
OH
OL
V
an input level is guaranteed to appear
as a logical one This parameter is to
be measured by performing a function-
al test at reduced clock speeds and
nominal timing (i e not minimum setup
and hold times or output strobes) with
the high level of all driving signals set
to V
applied to the device
V
an input level is guaranteed to appear
as a logical zero to the device This pa-
rameter is measured in the same man-
ner as V
levels set to V
voltages applied to the device
V
which an output placed in a logical one
state will converge when loaded at the
maximum specified load current
V
which an output placed in a logical zero
state will converge when loaded at the
maximum specified load current
The threshold region is the range of in-
put voltages between V
A signal is Valid if it is in one of the
valid logic states (i e above V
low V
nal is deemed valid at the instant it en-
ters a valid state
A signal is Invalid if it is not in a valid
logic state i e when it is in the thresh-
old region between V
ing specifications a signal is deemed
invalid at the instant it enters the
threshold region
All input signals may be characterized
as V
t
The period of clock signal is designat-
ed at t
mnemonic of the clock signal being
specified
F k
IH
IL
OH
OL
is the d c input level below which
is the d c input level above which
IH
is the maximum d c output level to
is the minimum d c output level to
L
10 ns
IL
e
) In timing specifications a sig-
and maximum supply voltages
Pxx
IH
0 4V V
but with all driving signal low
where xx represents the
IL
IH
and minimum supply
e
IL
2 4V t
and V
IL
and V
R k
IH
IH
IH
In tim-
10 ns
or be-
14
Rise Time
Fall Time
Pulse Width High
Pulse Width Low
Setup Time
Hold Time
Delay Time
Rise times are designated at t
where yy represents a mnemonic of
the signal whose rise time is being
specified t
V
Fall times are designated as t
where yy represents a mnemonic of
the signal whose fall time is being
specified t
V
The high width is designated as t
where zz represents the mnemonic of
the input or output signal whose pulse
width is being specified High pulse
widths are measured from V
The low pulse width is designed as
t
monic of the input or output signal
whose pulse width is being specified
Low pulse widths are measured from
V
Setup times are designated as t
where ww represents the mnemonic of
the input signal whose setup time is be-
ing specified relative to a clock or
strobe input represented by mnemonic
xx Setup times are measured from the
ww Valid to xx Invalid
Hold times are designated as t
where ww represents the mnemonic of
the input signal whose hold time is be-
ing specified relative to a clock or
strobe input represented by mnemonic
xx Hold times are measured from xx
Valid to ww invalid
Delay times are designated as t
monic of the input reference signal and
yy represents the mnemonic of the out-
put signal whose timing is being speci-
fied relative to xx The mnemonic may
optionally be terminated by an H or L to
specifiy the high going or low going
transition of the output signal Maxi-
mum delay times are measured from xx
Valid to yy Valid Minimum delay times
are measured from xx Valid to yy inval-
id This parameter is tested under the
load conditions specified in the Condi-
tions column of the Timing Specifica-
tion section of this data sheet
l
WzzL
H
IH
IL
IL
l
L
to V
where xx represents the mne-
where zz represents the mne-
IL
Ryy
Fyy
is measured from V
is measured from V
IH
to V
Hxxww
Dxxyy
Swwxx
WzzH
IH
IL
Ryy
IH
Fyy
to
to