74actq16244sscx-nl Fairchild Semiconductor, 74actq16244sscx-nl Datasheet - Page 5

• Manufacturer Part Number: 74actq16244sscx-nl
• Description: 74actq16244 16-bit Buffer/line Driver With 3-state Outputs
• Manufacturer: Fairchild Semiconductor

FACT Noise Characteristics
The setup of a noise characteristics measurement is critical
to the accuracy and repeatability of the tests. The following
is a brief description of the setup used to measure the
noise characteristics of FACT.
Equipment:
Procedure:
1. Verify Test Fixture Loading: Standard Load 50 pF,
2. Deskew the HFS generator so that no two channels
3. Terminate all inputs and outputs to ensure proper load-
4. Set the HFS generator to toggle all but one output at a
5. Set the HFS generator input levels at 0V LOW and 3V
Hewlett Packard Model 8180A Word Generator
PC-163A Test Fixture
Tektronics Model 7854 Oscilloscope
500
have greater than 150 ps skew between them. This
requires that the oscilloscope be deskewed first. It is
important to deskew the HFS generator channels
before testing. This will ensure that the outputs switch
simultaneously.
ing of the outputs and that the input levels are at the
correct voltage.
frequency of 1 MHz. Greater frequencies will increase
DUT heating and affect the results of the measure-
ment.
V
Input pulses have the following characteristics: f
t
HIGH for ACT devices and 0V LOW and 5V HIGH for
AC devices. Verify levels with an oscilloscope.
f
FIGURE 1. Quiet Output Noise Voltage Waveforms
OHV
3 ns, skew
:
and V
.
OLP
are measured with respect to ground reference.
150 ps.
1 MHz, t
r
3 ns,
5
V
• Determine the quiet output pin that demonstrates the
• Measure V
• Verify that the GND reference recorded on the oscillo-
V
• Monitor one of the switching outputs using a 50
• First increase the input LOW voltage level, V
• Next decrease the input HIGH voltage level, V
• Verify that the GND reference recorded on the oscillo-
OLP
ILD
greatest noise levels. The worst case pin will usually be
the furthest from the ground pin. Monitor the output volt-
ages using a 50
SMB type connector on the test fixture. Do not use an
active FET probe.
worst case transition for active and enable. Measure
V
case active and enable transition.
scope has not drifted to ensure the accuracy and repeat-
ability of the measurements.
cable plugged into a standard SMB type connector on
the test fixture. Do not use an active FET probe.
output begins to oscillate or steps out a min of 2 ns.
Oscillation is defined as noise on the output LOW level
that exceeds V
exceed V
oscillation occurs is defined as V
the output begins to oscillate or steps out a min of 2 ns.
Oscillation is defined as noise on the output LOW level
that exceeds V
exceed V
oscillation occurs is defined as V
scope has not drifted to ensure the accuracy and repeat-
ability of the measurements
OHP
FIGURE 2. Simultaneous Switching Test Circuit
and V
/V
OLV
and V
IHD
and V
IH
IH
OLP
:
limits. The input HIGH voltage level at which
limits. The input LOW voltage level at which
OHV
OHP
and V
IL
IL
:
on the quiet output during the worst
limits, or on output HIGH levels that
limits, or on output HIGH levels that
/V
coaxial cable plugged into a standard
OHV
OLV
:
on the quiet output during the
ILD
IHD
.
.
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IL
:
, until the
IH
coaxial
, until