Z-Activet Probe
Deskew Fixture
Instructions
071-1768-01
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Tip-Clip and Z-Active are trademarks of Tektronix, Inc.
Contacting Tektronix
Tektronix, Inc.
14200 SW Karl Braun Drive
PO Box 500
Beaverton, OR 97077
USA
For product information, sales, service, and technical
support:
H In North America, call 1--800--833--9200.
H Worldwide, visit www.tektronix.com to find contacts
in your area.
Warranty Information
For warranty information, go to www.tektronix.com,
click Support, and then use the provided links to search
for your product’s warranty.
Equipment Recycling
This product complies with the European Union’s
requirements according to Directive 2002/96/EC on
waste electrical and electronic equipment (WEEE). For
information about recycling options, check the Support/
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Z-Active Probe Deskew Fixture
The Z-Active Probe Deskew fixture (067-1586-00)
provides an edge source to time align (deskew) signals at
the probe tips. It allows you to deskew the Tip-Clip
assemblies that you will install on your circuit board
resulting in improved reliability and accuracy. The
fixture also provides a method to adjust the offset and
gain calibration function for the probes. The fixture
supports the Z-Active series oscilloscope probes.
The fixture is powered by one of the USB ports of the
oscilloscope. For best results, allow the oscilloscope to
warm up for 20 minutes before continuing with these
instructions.
Assemble the fixture before initial use. Mount the circuit
board to the fixture base and then install the solder box.
Use the screws provided.
Use the fixture with your Tektronix oscilloscope to
optimize the gain and offset accuracy of your Z-Active
probes. Refer to the DC Probe Calibration Procedure
for detailed instructions for performing the DC Cal
procedure. Perform the DC Calibration procedure before
the Deskew procedure.
Use the fixture to time align the signals at your probe
tips. Several different deskew methods are available:
H Use the hand-held adapters to deskew the probes
without any additional equipment.
H Use the fixture with the Tip-Clip assemblies directly.
H Use the fixture with Tip-Clip assemblies and solder
pins.
Refer to Deskew Procedure on page 3 for the detailed
deskew instructions.
DC Probe Calibration Procedure
Note the following:
H Perform the DC Cal procedure before the deskew
procedure.
H The USB cable does not need to be connected for the
DC probe calibration procedure.
Optimize Gain and Offset Accuracy
1. Connect the probe to the oscilloscope.
2. Connect the DC PROBE CAL output from the
oscilloscope to the BNC connector on the deskew
fixture.
3. Connect the probe to the fixture as shown in
Figure 1 on page 2.
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Figure 1: DC Probe Calibration connections
NOTE. Replace the Tip-Clipt assemblies
if damaged or worn.
4. Select Probe Cal . . . from the Vertical menu.
5. Select the oscilloscope channel to which the probe is
attached.
6. Select Clear Probecal to erase any previous
calibration data.
7. Select the Calibrate Probe button.
The oscilloscope will perform a DC calibration
operation on the selected probe. The result appears in
the Probe Status readout.
8. When the operation is finished, remove the
connections from the fixture.
Check the Calibration Status
1. Select Probe Cal . . . from the Vertical menu.
2. Select the channel to which the probe is attached and
then check the Probe Status readout:
H Initialized. The probe has not been calibrated on
the selected channel; perform the DC probe calibration procedure.
H Pass. The probe has been calibrated on the se-
lected channel.
H Fail. The probe has not been calibrated; repeat
the procedure. If the test continues to fail, trou-
2
bleshoot the problem; do not continue with the
deskew procedure.
Deskew Procedure
Deskew aligns signals to compensate for differing signal
delays from cables of different lengths. The oscilloscope
deskew feature applies deskew values after it completes
each acquisition. The deskew values do not affect logic
triggering. Deskew has no affect on XY and XYZ
display formats.
1. Connect the deskew fixture to a USB power source.
2. Connect the probes to the oscilloscope.
NOTE. To get the most accuracy, use the
same Tip-Clip assemblies with the deskew
fixture that you will install on your circuit
board.
3. Connect the probes to the fixture using one of the
following steps:
a. Connect the probes to the fixture using the
clamps on the fixture and the Tip-Clip
assemblies as shown in Figure 2.
NOTE. Refer to Preparing the Tip-Clip
Assemblies with the Deskew Fixture on
page 7 for instructions on preparing the
Tip-Clip assemblies for use with the
fixture.
Place one probe in the
clamponeachsideof
the fixture.
Figure 2: Connecting probes to the Deskew fixture using
the Tip-Clip assemblies
3
b. Connect the probes using the hand held adapter
as shown in Figure 3 on page 4.
NOTE. If you are using a single Tip-Clip
assembly and a hand-held adapter, adjust
the clamp and fixture as necessary to
provide access to the circuit board pads
for the hand-held adapter.
Hold each probe on the
circuit board pads on
the top of the fixture.
Figure 3: Usingthe hand-held adapters for the Deskew procedure
4. Select a reference channel with which all other
channels will be deskewed. This is typically Channel
1, but can vary depending on your setup.
5. Select Deskew from the Vertical menu.
6. Select Channel 1 and set the Deskew to 0.0 s.
7. Display all channels to deskew, including the
reference channel.
8. Push the AUTOSET button on the oscilloscope.
9. Select Horizontal/Acquisition Setup from the
Horiz/Acq menu and then select the Acquisition
tab. Select Average and #ofWfms16.
10. Adjust the trigger level to get a stable trigger.
4
11. (Optional) Use a voltmeter to measure the deskew
signal common mode voltage for your application at
the Common Mode Out terminals. Adjust the
voltage using the COMMON MODE ADJUST
control on the fixture.
12. (Optional) Adjust the deskew amplitude for your
application on the oscilloscope display using the
AMPLITUDE ADJUST control on the fixture
(probes not shown).
COMMON MODE ADJUST
AMPLITUDE ADJUST
Figure 4: Adjustment locations
13. Adjust the vertical SCALE and POSITION (with
active probes, adjust the offset as needed) for each
channel so that the signals overlap and are centered
on screen. Make sure all channels being deskewed
are at the same volts/div setting. Deskew the
channels at the same level as your planned signal
measurement.
14. Adjust the horizontal POSITION so that a triggered
rising edge of the reference channel is at center
screen.
15. Adjust the horizontal SCALE so the differences in
the channel delays are clearly visible.
16. Adjust the horizontal POSITION again so that the
first rising edge of the reference channel is at center
screen.
17. Select Deskew from the Vertical menu.
18. Select one of the channels to match to the reference
channel.
5
NOTE. Do the next step at a signal
amplitude within the same attenuator
range (vertical scale) as your planned
signal measurements. Any change to the
vertical scale after the deskew is complete
can change the attenuator setting and
give a slightly different signal path. This
signal path difference can cause as high
as 100 ps variation in timing skew
between channels.
19. Adjust the deskew time for that channel so that its
signal aligns with that of the reference channel.
20. Repeat steps 18 and 19 for each additional channel
that you want to deskew.
6
Preparing the Tip-Clip Assemblies with the
Deskew Fixture
The deskew fixture provides a means to hold the probes
and any size Tip-Clip assembly for performing the
deskew procedures. Choose one of the following methods for preparing the assemblies for use with the deskew
fixture:
H Use the Tip-Clip assemblies with either large or
small resistors and connect them directly to the fixture.
H Use the Tip-Clip assemblies with solder pins to
create an assembly for easy handling while performing the deskew procedure.
Connecting the Tip-Clip Assemblies Directly to the
Deskew Fixture
To use the Tip-Clip assemblies directly with the fixture,
bend the resistors as shown in Figure 5. and and install
the assemblies on the fixture. After performing the
deskew procedure, trim the resistors at the bend.
0.080 in0.080 in
Bend 90°
Figure 5: Bend the resistor leads
If you are using the small resistor Tip-Clip assemblies,
install the assemblies on the fixture as shown in Figure 6.
Small resistors
Holes accept two small
resistor leads each.
Figure 6: Installing the small resistor Tip-Clip assemblies
on the fixture
7
If you are using the large resistor Tip-Clip assemblies,
install the assemblies on the fixture as shown in Figure 7.
NOTE. The large resistor leads are too
large to insert two of them in the same
holes on the fixture.
Large resistors
Figure 7: Installing the large resistor Tip-Clip assemblies
on the fixture
Close the clamp to secure the Tip-Clip assembly as
shown in Figure 8.
NOTE. To avoid unnecessary wear on the
clamp elastomer, leave the top clamp in
the open position when not using the
fixture.
Figure 8: Secure the Tip-Clip assembly
Using the Tip-Clip Assemblies with the Solder Pins
Refer to Figure 9 through Figure 15 to prepare the
Tip-Clip connectors for use with solder pins on the
fixture.
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Locate the solder box for
building probe Tip-Clip
assembly.
Figure 9: Locate the solder box
Insert two pins (Tektronix part
number 131-7931-00) into the
middle of the fixture.
Figure 10: Insert the solder pins into the solder box
Medium flex
assembly
0.080 in0.080 in
Trim resistor leads to 0.080 in.
0.080 in
Figure 11: Trim the resistor leads
Slide the Tip-Clip assembly to
the pin heads and then add the
second Tip-Clip assembly.
Figure 12: Position the Tip-Clip assemblies
Small flex
assembly
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Solder resistor leads
to the pins.
Figure 13: Solder the Tip-Clip assemblies to the solder pins
Insert the assembly in the
holder on the fixture.
Figure 14: Inset the assembly into the fixture holder
NOTE. To avoid unnecessary wear on the
clamp elastomer, leave the top clamp in
the open position when not using the
fixture.
Figure 15: Secure the Tip-Clip assembly
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