The servicing instructions are for use by qualified
personnel only. To avoid personal injury, do not
perform any servicing unless you are qualified to
do so. Refer to all safety summaries prior to
performing service.
pending. Information in this publication supercedes that in all previously
published material. Specifications and price change privileges reserved.
Tektronix, Inc., P.O. Box 500, Beaverton, OR 97077
TEKTRONIX, TEK, TEKPROBE, and SureFoot are registered trademarks of
Tektronix, Inc.
FlexLead and KlipChip are trademarks of Tektronix, Inc.
WARRANTY
Tektronix warrants that this product will be free from defects in materials and
workmanship for a period of three (3) months from the date of shipment. If any such
product proves defective during the three–month period, Tektronix, at its option, either
will repair the defective product without charge for parts and labor, or will provide a
replacement in exchange for the defective product.
In order to obtain service under this warranty, Customer must notify Tektronix of the
defect before the expiration of the respective warranty period and make suitable
arrangements for the performance of service. Customer shall be responsible for packaging
and shipping the defective product to the service center designated by Tektronix, with
shipping charges prepaid. Tektronix shall pay for the return of the product to Customer if
the shipment is to a location within the country in which the Tektronix service center is
located. Customer shall be responsible for paying all shipping charges, duties, taxes, and
any other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or
improper or inadequate maintenance and care. Tektronix shall not be obligated to furnish
service under this warranty a) to repair damage resulting from attempts by personnel other
than Tektronix representatives to install, repair or service the product; b) to repair damage
resulting from improper use or connection to incompatible equipment; c) to repair any
damage or malfunction caused by the use of non–Tektronix supplies; or d) to service a
product that has been modified or integrated with other products when the effect of such
modification or integration increases the time or difficulty of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THE
LISTED PRODUCTS IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR
IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE TEKTRONIX’ RESPONSIBILITY TO REPAIR OR REPLACE
DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY
PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY.
TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE OR ANY INDIRECT ,
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE
OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF
THE POSSIBILITY OF SUCH DAMAGES.
Review the following safety precautions to avoid injury and prevent
damage to this product or any products connected to it. To avoid
potential hazards, use this product only as specified.
Only qualified personnel should perform service procedures.
To Avoid Fire or Personal Injury
Connect and Disconnect Properly. Do not connect or disconnect probes
or test leads while they are connected to a voltage source.
Connect and Disconnect Properly. Connect the probe output to the
measurement instrument before connecting the probe to the circuit
under test. Disconnect the probe input and the probe ground from the
circuit under test before disconnecting the probe from the measurement instrument.
Observe All Terminal Ratings. To avoid fire or shock hazard, observe all
ratings and markings on the product. Consult the product manual for
further ratings information before making connections to the product.
Do Not Operate Without Covers. Do not operate this product with
covers or panels removed.
Avoid Exposed Circuitry. Do not touch exposed connections and
components when power is present.
Do Not Operate With Suspected Failures. If you suspect there is damage
to this product, have it inspected by qualified service personnel.
Do Not Operate in Wet/Damp Conditions.
Do Not Operate in an Explosive Atmosphere.
Safety Terms and Symbols
Terms in This Manual. These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that
could result in injury or loss of life.
P6245AD Instruction Manual
v
General Safety Summary
CAUTION. Caution statements identify conditions or practices that
could result in damage to this product or other property .
vi
P6245AD Instruction Manual
Preface
This manual is divided into user information and servicing
information. These sections are described below.
User Information
This section contains the information necessary to install and use the
P6245AD.
HGetting Started
This section contains the product description, description of
accessories, probe setup configuration, and how to check the
probe for normal operation.
HOperating Basics
This section contains basic information and operating suggestions
for optimal probe performance
HSpecifications
This sections list the specifiecations for this product.
Service Information
This section contains the information necessary to maintain and
service the P6245AD.
HTheory of Operation
HPerformance Verification
HAdjustments
HMaintenance
HTroubleshooting
Replaceable Parts
This section lists the replaceable parts, stadard accessories, and
optional accessories that are available for this product.
P6245AD Instruction Manual
vii
Preface
Contacting Tektronix
Product
support
Service
support
Toll–free
Number
For questions about using Tektronix measurement
products, call toll free in North America:
1-800-833-9200
6:00 a.m. – 5:00 p.m. Pacific time
Or contact us by e-mail:
tm_app_supp@tek.com
For product support outside of North America,
contact your local Tektronix distributor or sales
office.
Tektronix offers a range of services, including
Extended Warranty Repair and Calibration services.
Contact your local Tektronix distributor or sales
office for details.
For a listing of worldwide service centers, visit our
web site.
In North America:
1-800-833-9200
An operator can direct your call.
viii
Postal
Address
Web site
Tektronix, Inc.
Department or name (if known)
P.O. Box 500
Beaverton, OR 97077
USA
www.tektronix.com
P6245AD Instruction Manual
Getting Started
Product Description
The Tektronix P6245AD is a 10X active FET probe with less than
1 pF input capacitance. The low input capacitance and high input
resistance minimize circuit loading over a wide bandwidth range.
The small profile and low-mass head of the P6245AD makes probing
crowded circuits by hand fast and easy. The accessory tips and
adapters enable the P6245AD to be used on a wide variety of circuit
architectures.
The P6245AD is powered through a TEKPROBE interface between
the compensation box of the probe and the oscilloscope. The
P6245AD may be used with nonTEKPROBE oscilloscopes and
instruments by using the optional Tektronix 1 103 Probe Power
Supply.
In order to fully appreciate the probe’s capabilities, please read theGetting Started and Operating Basics sections of this manual.
Standard Accessories
The P6245AD is shipped with the following standard accessories:
Hstandard probe tips
HSureFoot adapter probe tips
HSMT KlipChip microcircuit test leads
HY-lead adapter
Hright-angle adapter
Hsignal-ground adapters
Hthree- and six-inch ground leads
Hlow-inductance ground lead
Hmarker rings
HInstruction Manual
P6245AD Instruction Manual
1–1
Getting Started
For service information, refer to the service section beginning at the
yellow page.
For part number information for standard and optional accessories,
refer to the Replaceable Parts section of this manual.
1–2
P6245AD Instruction Manual
Features and Accessories
The P6245AD is provided with several features and accessories
designed to make probing and measurement a simpler task. Please
take a moment to familiarize yourself with these items and their
uses.
Probe Head Assembly. The probe head is
designed for ease of use and high performance.
Its small size makes it easy to handle in tight
areas.
Probe Tip
Socket
Ground
Socket
Stabilization
Notch
The probe tip socket is sized to easily press onto
0.025 inch pins for direct access. The ground
socket provides a short ground path for high
fidelity ground connections.
The stabilization notch permits you to use
adjacent pins to reduce stresses on the probe
and pins. See pages 1–6 and 2–8 for more
information.
Push-In Probe Tip
TEKPROBE Interface. The TEKPROBE
interface provides a communication path between
the probe and the oscilloscope. Contact pins
provide power, signal, offset, and probe
characteristic data transfer. See page 4–2 for
more information.
If your oscilloscope does not support the
TEKPROBE interface, you can use the optional
1103 probe power supply as an effective
interface. Contact your local Tektronix representative for more information.
Push-in Probe Tip. Use the push-in probe tip for
general purpose probing by hand. The tip may
also be used as a temporary test point. See page
2–7 for more information.
The push-in probe tip may also be used with the
other socketed leads and adapters.
P6245AD Instruction Manual
1–3
Features and Accessories
Installing the Push-in Probe Tip. Attach the
push-in probe tip by seating the tip into the probe
tip socket and pushing the tip in until it is seated.
Either end of the tip may be used. Do not forcethe tip. Also, be careful not to poke yourself with
the sharp probe-tip. To remove the tip, gently
grab the tip with small pliers and pull the tip out.
SureFoot probe tip. The SureFoot tip is an
integral probe tip and miniature guide that
enables fault-free probing of fine-pitch SMD
packages. Attach the SureFoot adapters the
same way as the push-in probe tips. They can be
used with any of the socketed accessory leads.
Right Angle
Adapter
The yellow, 0.050 inch SureFoot tip is compatible
with 50 mil JEDEC packages such as SOIC,
PLCC, CLCC, etc.
The blue, 0.025 inch SureFoot tip is compatible
with 0.65 mm JEDEC and EIAJ packages.
The red, 0.5 mm SureFoot tip is compatible with
EIAJ packages.
Right-angle adapter. Use the right-angle
adapter for low-profile probing of 0.025 inch
diameter square pins.
The right-angle adapter allows the P6245AD to
lie flat against a circuit board. This enables
probing in vertical circuits such as computer or
communications backplanes, or in tight areas
such as between circuit cards.
The right-angle adapter can be used directly with
the probe head, or attached to the Y-lead adapter
or ground leads.
The right-angle adapter is attached the same way
as the push-in probe tip, and can be easily
removed by hand.
1–4
P6245AD Instruction Manual
Y-lead
Adapter
Features and Accessories
Y-lead adapter. Use the Y-lead adapter to extend
the physical reach of the probe and ground when
necessary. The Y-lead adapter accepts any of the
probe tips or adapters, and can be pushed
directly onto 0.025 inch pins.
When selecting the grounding connection,
maintain as short a ground path as possible.
Refer to page 2–2 for more information.
To attach the Y-lead adapter, gently press the
lead pins into the probe head tip and ground
receptacles. Using the black lead for ground is
recommended.
3- and 6-inch ground leads. Use the three- and
six-inch ground leads for general probing. The
socketed end of the leads may be connected to
any of the probe tips and adapters, or fitted onto
0.025 inch pins.
To attach the ground leads, press and rotate the
lead pin connector into the ground socket on the
probe head. The lead may be removed by simply
pulling the pin out by hand.
When selecting the grounding connection,
maintain as short a ground path as possible.
Refer to page 2–2 for more information.
Low-inductance ground lead. Use the
low-inductance ground adapter to substantially
reduce ground lead inductance. Because the
ground lead simply touches the ground reference,
you can easily move the probe to different points
on the device under test.
To attach, press the ground lead into the probe
head gound socket.
P6245AD Instruction Manual
When selecting the grounding connection,
maintain as short a ground path as possible.
Refer to page 2–2 for more information.
1–5
Features and Accessories
Signal Ground
Adapter
Signal-Ground Adapter. The signal-ground
adapter is ideal for use with signal/ground pairs
on 0.100 inch header pins (such as FlexLead
adapters).
Attach the signal-ground adapter by gently
pressing it into the ground socket on the probe
head.
Be sure to use the stabilization notch whenever
possible. See page 2–8 for further details.
FlexLead
Adapter
KlipChip
Y-lead
Adapter
Color Marker
Bands
SMT KlipChip. Use the SMT KlipChip test clips
to access fragile, dense circuitry.
KlipChip test clips can be connected to the Y-lead
or three- or six-inch ground leads. Simply press
the lead socket into the KlipChip handle.
The KlipChip body freely turns, allowing better
probe orientation. To reduce stress and provide a
lower profile on components being tested, the
flexible sleeve of the KlipChip bends up to a
35 degree angle.
Color Marker Bands. Attach matching pairs of
the color marker bands onto the cable at the
head and compensation box of each probe. The
marker bands enable quick verification of which
probe is connected to which instrument channel.
1–6
P6245AD Instruction Manual
Configuration
The P6245AD provides the oscilloscope with the probe model
number, serial number, and attenuation factor. When connected to a
TEKPROBE oscilloscope, display readouts are corrected for the
probe attenuation factor, the instrument input is set to 50 W, and the
coupling is set to DC.
CAUTION. Do not attempt to install the P6245AD on a
nonTEKPROBE connector. Damage to the probe and connector may
result. If your oscilloscope does not support the TEKPROBE
interface, use the optional Tektronix 1103 Probe Power Supply .
If the P6245AD is used with the Tektronix 1103 Probe Power Supply,
be sure to have a 50 W termination at the oscilloscope. Also, set the
oscilloscope channel coupling to DC.
The probe offset control is controlled by the oscilloscope. If the
oscilloscope used does not support the TEKPROBE interface, the
offset controls on the optional Tektronix 1103 Probe Power Supply
can be used.
Probe Offset
The probe offset is adjustable to permit operation within the linear
range of the probe. Using the offset to cancel DC signal components
enables optimal probe performance. See Figure 1–1 on page 1–8.
NOTE. See your oscilloscope manual for specific instructions on its
operation and offset control.
P6245AD Instruction Manual
1–7
Configuration
To set the probe offset, follow these steps:
1. Set the oscilloscope coupling to GND.
2. Use the vertical position control to set a zero reference level on
3. Set the oscilloscope coupling to DC and 5 V/div.
4. Attach the probe to the circuit.
5. Adjust the probe offset to bring the trace to the oscilloscope zero
6. Change the volts/division setting to the desired range, adjusting
NOTE. The P6245AD has a ±10 V offset range. The linear operating
range is ±8 V. See Figure 1–1. Also, see page 2–1 for more
information.
the oscilloscope display .
reference.
the offset to keep the trace on the zero reference level.
If cursors are used on a TEKPROBE oscilloscope, the zero reference
will be at the probe offset voltage.
Nonoperating Range (+40 V Maximum Non-destructive Input Voltage )
+18 V
+10 V
+8 V
0 V
–8 V
–10 V
–18 V
Nonoperating Range (–40 V Maximum Non-destructive Input Voltage )
+10 V
Maximum Offset RangeMaximum AC Signal Amplitude
–10 V
Figure 1–1: Dynamic and Offset Limitations
1–8
P6245AD Instruction Manual
Functional Check
After installing the probe on the oscilloscope, a functional check
may be performed using the PROBE COMPENSATION connections
on the front panel of the oscilloscope. See Figure 1–2.
Figure 1–2: Probe Functional Check Connections
1. Connect the probe to the oscilloscope.
2. Set the oscilloscope to display the probe’s channel.
3. Using a ground lead and a SMT KlipChip, connect the probe
ground to the PROBE COMPENSATION ground connection on
the oscilloscope.
4. Using a standard tip, hold the probe to the SIGNAL terminal on
the oscilloscope.
5. Press AUTOSET (or adjust the oscilloscope) to display the
calibration waveform.
P6245AD Instruction Manual
1–9
Functional Check
NOTE. If your instrument supports probe calibration routines, now is
a good time to perform them.
6. Disconnect the probe from the SIGNAL terminal and ground the
probe tip. (Connect the KlipChip to the probe tip.)
7. With the probe offset set to 0.0 V, the oscilloscope display should
be at the ground reference.
8. Set the oscilloscope volts/division to 5 V.
9. Adjust the probe offset. The displayed waveform should vary
between approximately +10 V and –10 V. (A +10 V offset
displays a –10 V level on your instrument.)
NOTE. If no waveform is displayed, check the vertical coupling to be
sure that it is set to DC.
If the offset adjustment has no effect, set the vertical coupling to DC.
If you are using the Tektronix 1103 Probe Power Supply, and the
waveform is distorted, check to make sure that the oscilloscope
termination is 50 W.
If the probe does not pass this functional check, go to the Troubleshooting section of this manual.
1–10
P6245AD Instruction Manual
Operating Basics
Operating Basics
Please follow these operating guidelines to get optimum performance from your P6245AD.
Maximum Nondestructive Input Voltage
The P6245AD is electrically protected against static voltage;
however, applying voltages above its design limits may damage the
probe tip amplifier. Please refer to the Specifications section of this
manual for the maximum operating voltage and frequency derating
information.
Input Linear Dynamic Range
The probe head amplifier used by the P6245AD has a limited linear
operating range. To keep the input linearity error less than 4% you
must limit the signal input voltage to ±8 V (including any DC
offset).
Use the DC offset adjustment to maintain the probe within its
dynamic range. The nominal offset adjustment range of the
P6245AD is ±10 VDC. For example: to offset a +5 VDC level in a
circuit, set the offset to +5 V.
NOTE. The probe can tolerate input voltages of ±40 V without
damage; however, the linearity error specification does not apply to
input voltages exceeding ±18 V (including any DC offset). See
Figure 1–1 on page 1–8.
P6245AD Instruction Manual
2–1
Operating Basics
Ground Lead Length
When you are probing a circuit, you should always use as short a
ground lead as possible between the probe head and circuit ground.
The series inductance added by the probe tip and ground lead can
result in a resonant circuit; this circuit may cause parasitic ringing
within the bandwidth of your oscilloscope. Refer to Figure 2–1.
Low-inductance
Ground
Three-inch
Ground
Six-inch
Ground
Figure 2–1: Waveform Distortion from Ground Lead Length
Ground Lead Inductance
When you touch your probe tip to a circuit element, you are
introducing a new resistance, capacitance, and inductance into the
circuit. Refer to Figure 2–2.
2–2
P6245AD Instruction Manual
R
Operating Basics
source
V
source
(Ground Lead)
L
gl
Probe R
1MW
in
Probe C
1pF
Figure 2–2: Ground Lead Equivalent Circuit
Ringing and rise time degradation can be masked if the frequency
content of the signal degradation is beyond the bandwidth of the
oscilloscope.
You can determine if ground lead effects may be a problem in your
application if you know the self-inductance (L) and capacitance (C)
of your probe and ground lead. Calculate the approximate resonant
frequency (f
) at which this parasitic circuit will resonate with the
0
following formula:
+
f
0
1
Ǹ
2p LC
in
The preceding equation shows that reducing the ground lead
inductance will raise the resonant frequency. If your measurements
are affected by ringing, your goal is to lower the inductance of your
ground path until the resulting resonant frequency is well above the
frequency of your measurements.
The low-inductance ground contacts described in Accessories can
help you reduce the effects of ground lead inductance on your
measurements.
P6245AD Instruction Manual
2–3
Operating Basics
2–4
P6245AD Instruction Manual
Helpful Hints
Follow these helpful hints to make probing easier and noise free.
Low-inductance Grounding
Placing a ground plane on top of a package being probed can
minimize ground lead length and inductance. See Figure 2–3.
Figure 2–3: Low-inductance Grounding
Attach a small piece of copper clad on top of the package and
connect it to the package ground connection. Use the low-inductance
ground lead provided with the P6245AD to keep the ground lead
length as short as possible.
P6245AD Instruction Manual
2–5
Helpful Hints
This method is very useful when making many measurements on the
same package. Using a ground plane on the package makes probing
the package easier, and avoids adding unnecessary ground lead
length and distortion.
SureFoot Grounding
If you cannot use the low-inductance grounding method recommended, the probe may be grounded to the package under test using
a SureFoot adapter. Refer to Figure 2–4.
2–6
Figure 2–4: Using a SureFoot Adapter for Grounding
Use a SureFoot adapter at the end of a short ground lead to connect
directly to the package ground. This method is preferred over using
an adjacent circuit ground because it is the shortest ground path
possible.
P6245AD Instruction Manual
Probe Tip Test Points
The push-in probe tip or a 0.025 square pin can be soldered into a
circuit to be used as a temporary test point. See Figure 2–5.
Solder the tip onto a lead or pin with a low-power soldering iron.
Press the probe head onto the tip to make a measurement, and then
pull the probe head off when you are done.
The probe tip may be removed and reused by desoldering it from the
circuit, and soldering it into another circuit in the future.
Helpful Hints
Solder
Figure 2–5: Using a Probe Tip as a Test Point
NOTE. It is not recommended that pieces of solid-core copper wire be
used as test points. If the wire breaks off in the probe tip socket, it
may be impossible to remove the wire, and it will prevent insertion of
other accessory tips.
P6245AD Instruction Manual
2–7
Helpful Hints
Probe Tip Stabilization
The P6245AD probe head has a stabilizing notch for use with 0.100
inch spaced header pins. See the probe head detail on page 1–3.
As the probe is pressed onto the header pin, an adjacent pin can be
inserted into the probe’s stabilizing notch. See Figure 2–6. This
prevents unnecessary force from being applied directly to the probe
tip or pins.
Stabilization Notch
Figure 2–6: Probe Tip Stabilizing Notch
The signal-ground adapter then rests on the stabilized pin without a
risk of its moving out of place.
2–8
P6245AD Instruction Manual
Specifications
Specifications
These specifications apply to a P6245AD when used with a
Tektronix TDS 684C (or similar) oscilloscope.
The probe and instrument must first be allowed to warm up for
20 minutes before measurements are taken.
CAUTION. Do not apply voltages beyond the nondestructive input
voltage range to the probe. Damage to the probe or circuit under test
may result.
Table 3–1: Warranted Electrical Specifications
DC Attenuation Accuracy
(probe only)
Output Zero±5 mV or less at output of probe
10:1 ±2%
±50 mV or less displayed on screen with
TEKPROBE interface
P6245AD Instruction Manual
3–1
Specifications
Table 3–2: T ypical Electrical Characteristics
Analog Bandwidth (probe only)1.0 GHz on ≥10GHz oscilloscope
Rise Time (probe only)400ps on ≥10 GHz oscilloscope
Linear Input Dynamic Range– 8 V to + 8 V.
(Equivalent to – 0.8 V to + 0.8 V
at the output of the probe.)
Linearity" 4% or less of dynamic range
Nondestructive Input Voltage Range
Input Resistance
Input Capacitance≤1.0 pF
Offset Range–10 V to +10 V
DC Offset Drift
Delay Time18.02 ns
– 40 V to + 40 V (DC + peak AC)
(See Figure 3–1.)
1MW at DC. (See Figure 3–3.)
100 mV/°C or less at output of probe
1 mV/°C or less displayed on screen with
TEKPROBE interface
3–2
P6245AD Instruction Manual
50 V
40 V
30 V
20 V
10 V
Specifications
20V at 400 MHz
8V at 1 GHz
0 V
Figure 3–1: T ypical Voltage Derating vs. Frequency
150 mV
100 mV
50 mV
0 mV
Display Error
–50 mV
–100 mV
1 GHz1 MHz10 MHz100 MHz
–150 mV
–20 V0 V–10 V10 V20 V
Figure 3–2: Typical Linearity Error vs V
P6245AD Instruction Manual
V
IN
IN
3–3
Specifications
10 MW
100 kW
10 kW
100 W
1 MW
1 kW
10 W
100 Hz1 GHz100 kHz1 kHz10 kHz1 MHz10 MHz 100 MHz
Figure 3–3: T ypical Input Impedance vs. Frequency
3–4
P6245AD Instruction Manual
T able 3–3: Physical Characteristics
Shipping Weight539.4 g (1.18 lb)
Cable Length4.6 m (15 ft)
T able 3–4: Environmental Characteristics
Operating Temperature0° C TO +50° C.
The environmental exposure is the procedure stated
in Tektronix Design Standard 062–2847–00 for Class
5 equipment.
Nonoperating Temperature– 40° C TO + 71° C.
Specifications
The environmental exposure is the procedure stated
in Tektronix Design Standard 062–2847–00 for Class
5 equipment.
HumidityThe environmental exposure is the procedure stated
in Tektronix Design Standard 062–2847–00 for Class
5 equipment.
Packaged Product Vibration and
Shock
AltitudeOperating: 15,000 ft.
The packaged product qualifies under the Distribution
Cycle 1 Assurance Level II for packaged products 0 –
20 lbs. Test 2 for Warehouse and Vehicle Stacking
(Compression) is omitted.
Tektronix standard 062–2858–00, Rev. B, Class 5.
Nonoperating: 50,000 ft.
P6245AD Instruction Manual
3–5
Specifications
3–6
P6245AD Instruction Manual
WARNING
The following servicing instructions are for use only by
qualified personnel. To avoid injury, do not perform any
servicing other than that stated in the operating instructions
unless you are qualified to do so. Refer to all safety
summaries before performing any service.
Service Information
Theory of Operation
There are no user replaceable parts within the probe or the
compensation box; however, this theory of operation is provided to
assist you in isolating failures to either the probe or the host
oscilloscope. Refer to Figure 4–1 for the probe’s simplified
schematic.
Probe HeadCompensation BoxOscilloscope
Probe Tip
Probe-Tip
Ampifier
Offset Ampifier
EEPROM
Signal Out
Probe ID Out
Clock In
±1V Offset
Offset to probe
+5
Offset
Gain
Probe
Cable
Figure 4–1: P6245AD Simplified Schematic Diagram
Probe Head and Cable Assembly
The probe head assembly contains an active amplifier circuit that
buffers and amplifies the input signal. The amplifier receives power
Offset
Zero
–5
+5V
–5V
Ground
TEKPROBE
Interface
P6245AD Instruction Manual
4–1
Theory of Operation
and an offset level from the compensation box assembly via the
cable assembly .
All signal amplification and buffering is performed in the probe head
assembly. No further amplification takes place in the compensation
box.
Compensation Box
The compensation box contains the following circuits:
The offset amplifier is used to offset the input signal’s DC compo-
nent so that it stays at the optimal point of the probe’s linear
dynamic range. For more information on the linear dynamic range
characteristic, refer to the notes on page 2–1.
The offset amplifier receives offset information as a ±1 VDC voltage
from the oscilloscope. The amplfier then amplifies it to match the
probe characteristics and applies it to the probe hybrid circuit.
The offset amplifier has two adjustments: offset zero and offset gain.
These adjustments rarely need attention; however, detailed
adjustment instructions are in the Adjustments section on page 4–8.
Probe Identification EEPROM
The probe identification EEPROM is used to configure the
oscilloscope to the probe. The EEPROM receives a clock input from
the oscilloscope, and information about the probe is passed to the
oscilloscope.
TEKPROBE Interface
4–2
The TEKPROBE interface provides a communication path between
the probe and the oscilloscope. Contact pins provide power, signal,
offset, and data transfer for the probe identification EEPROM.
P6245AD Instruction Manual
Theory of Operation
Figure 4–2 shows the TEKPROBE interface pin functions. Refer to
the service documenation for your oscilloscope for more detailed
specifications.
–15 V
–5V
Offset
Ground
Signal
Data
Clock
+5 V
+15 V
Figure 4–2: TEKPROBE Interface
P6245AD Instruction Manual
4–3
Performance Verification
Equipment Required
Table 4–1: Equipment Required for Performance Verification
Performance
Item Description
OscilloscopeTEKPROBE interfaceTektronix TDS 684C
TEKPROBE Power SupplyTektronix 1103
DC Power Supply10.00±.01 VDC at 1 mATektronix PS281
DC Voltmeter0.5% accuracy at 2 VDCTektronix CDM250
Requirement
Recommended Example
Feedthrough Termination
BNC to BNC coaxial cable
BNC to Banana adapterBNC Female to Dual
50 W± 0.50 W
50 W coaxial cable
Banana
Equipment Setup
1. Connect the probe to the oscilloscope.
2. Connect a Y-lead adapter with KlipChip adapters attached to the
P6245AD.
3. Turn on the oscilloscope and enable the channel.
4. Set the channel’s vertical offset to 0.00 V.
5. Turn on the power supply and set to +2.00 VDC.
6. Connect the meter to measure the power supply output.
7. Allow 30 minutes for the equipment to warm up.
011–0129–00
012–1342–00
103–0090–00
4–4
P6245AD Instruction Manual
NOTE. If your oscilloscope has a probe calibration routine, run it
before making any of the following checks. Refer to the oscilloscope’s instruction manual for more information.
Offset Zero
Use this procedure to verify the offset zero of the probe.
1. Ground the probe tip by connecting the probe tip to the probe
ground socket. (Connecting the two KlipChip adapters together is
recommended.)
2. Set the channel’s vertical offset to 0.00 V.
Performance Verification
3. Measure the displayed DC level.
The displayed DC level should be 0.00 V ±50 mV. (±5 mV when
measured directly without the probe attenuation factor .)
P6245AD Instruction Manual
4–5
Performance Verification
DC Accuracy
Use this procedure to verify the DC accuracy of the probe. Before
beginning, read the procedure through completely.
1. Connect the test equipment as shown in Figure 4–3.
2. Attach the probe to a TEKPROBE interface on the 1103 power
supply.
3. Set the 1103 offset VAR/0V to 0V.
4. Set the multimeter to read DC volts.
5. Connect the probe tip and ground to the power supply using the
Y-lead and KlipChip adapters.
6. Allow 30 minutes for the equipment to warm up.
Digital Multimeter
+
–
50 W Precision
BNC to Dual
Banana Adapter
Terminator
Figure 4–3: P6245AD DC Accuracy Setup
7. Set the power supply to +2.000 V. Record the power supply
output as Vmax.
8. Measure and record the multimeter reading as M1.
1103
Power Supply
Power Supply
–+
4–6
9. Set the power supply to –2.000 V. Record the power supply
output as Vmin.
P6245AD Instruction Manual
Performance Verification
10.Measure and record the multimeter reading as M2.
NOTE. If you are unable to set the power supply precisely, record the
actual readings and determine the absolute difference.
|Vmax – Vmin| = difference.
Divide the difference by 10 to account for the probe’s ideal
attenuation factor. For example: 0.4 is the difference between +2
and –2, divided by 10.
11. Determine the percent error by using the formula below:
%Error + [
The calculated error should be ≤2%.
NOTE. An unaccceptable error value may result if a low tolerance
termination is substituted for the recommended termination.
M1 * M2
0.4
* 1] 100%
P6245AD Instruction Manual
4–7
Adjustments
The P6245AD has two internal controls: offset zero and offset range.
These controls rarely need to be adjusted, and only should be
changed after a probe calibration and functional check has been
performed on the oscilloscope.
To make adjustments to the probe, the compensation box top cover
needs to be removed with the optional release tool. Refer to page
4–12. Use the optional adjustment tool for making any adjustments.
Adjustment Locations
Refer to Figure 4–4 for the location of the offset zero and offset
range controls.
EEPROM
4–8
Offset Range
Adjust
Figure 4–4: P6245AD Adjustment Locations
Offset Amp
Offset Zero
Adjust
P6245AD Instruction Manual
Offset Zero
Use this procedure to adjust the offset zero of the probe.
NOTE. If your oscilloscope supports a probe calibration routine,
clear the probe calibration constants at this time.
If the offset zero is adjusted, perform a functional check of the offset
range before closing the compensation box.
1. Ground the probe tip by connecting the probe tip to the probe
ground socket.
Adjustments
2. Set the vertical offset of the channel to 0.00 V.
3. Measure the displayed DC level.
4. Adjust Offset Zero for 0.00 ± 50 mV. (±5 mV when measured
directly without attenuation factor .)
P6245AD Instruction Manual
4–9
Adjustments
Offset Range
Use this procedure to adjust the offset range of the probe. The offset
zero of the probe should be checked before making any adjustment
to the offset range.
The offset range of the probe is approximately –10 to +10 volts. The
offset range is not warranted; however , this adjustment procedure is
provided for your convenience.
NOTE. If you are using an 1103 Probe Power Supply, make sure that
the oscilloscope is set to 50 W termination with DC coupling.
See Figure 4–4 for the location of the offset range adjustment.
1. Set the power supply (using the DMM) to +10.00 VDC. (If
10.00 V cannot be set exactly, set the power supply just below
10.00 V.)
2. Connect the probe to the power supply as shown in Figure 4–3.
3. Set the channel’s vertical offset to match the DMM reading.
4. Set the vertical range of the channel to 0.1 V/div.
5. Observe the DC value of the displayed trace.
6. Adjust Offset Range for an oscilloscope reading that matches the
DMM reading.
NOTE. After the offset zero and offset range have been adjusted,
perform a probe calibration and functional check to verify
performance.
4–10
P6245AD Instruction Manual
Maintenance
This section details the maintenance and repair procedures for the
P6245AD.
Replacing TEKPROBE Interface Pins
TEKPROBE interface pins can stick and fail to make contact after
time. Periodically check to see that each of the interface pins move
freely and fully extends out of the interface. If any pin fails to move
freely and fully extend, it should be replaced.
To remove a TEKPROBE interface pin, firmly grasp the pointed tip
with pliers and pull the pin out of the connector. See Figure 4–5.
No tools are required to install a replacement pin. Insert a new pin
into the connector socket as far as possible using finger pressure. If
necessary, seat the pin into the connector by pressing the tip gently
but firmly against a hard surface, such as a wood block or table top.
Figure 4–5: Replacing TEKPROBE Interface Pins
P6245AD Instruction Manual
4–11
Maintenance
Removing and Replacing the Compensation Box Covers
Follow these steps to open the compensation box.
1. Press the optional release tool pins into the compensation box
cover catches and gently lift the cover off a small distance. Refer
to Figure 4–6.
2. Hold the open edge apart, and use the tool to open the other side
of the compensation box.
3. With both sides of the box open, gently separate the two halves
of the compensation box.
Cover
Catches
Figure 4–6: Removing the Compensation Box Covers
4–12
P6245AD Instruction Manual
Maintenance
To replace the covers, follow these steps:
1. Align the TEKPROBE interface and the strain relief notches with
the tabs on the cover. Refer to Figure 4–7.
2. Press the cover catches in so that the cover can be lowered.
3. Slide the tab into the notch.
4. Firmly press the pieces together until the cover catches snap into
place.
Tab
Figure 4–7: Replacing the Compensation Box Cover
P6245AD Instruction Manual
4–13
Maintenance
Removing and Replacing the TEKPROBE Interface Collar
To remove the TEKPROBE interface collar , firmly grasp the
compensation box body with one hand, and the TEKPROBE
interface collar with the other hand. Firmly pull the interface collar
off.
To replace the collar , first note the pin configuration on the
compensation box, and their holes in the interface collar . The group
of three pins fit through the smaller of the two holes in the interface
collar. See Figure 4–8.
Align the tab to the slot and gently press the two pieces together . See
Figure 4–8.
Once installed, the TEKPROBE collar should rotate freely to lock
and unlock.
4–14
Tab
Slot
Figure 4–8: Replacing the TEKPROBE collar
P6245AD Instruction Manual
Inspection and Cleaning
To prevent damage to probe materials, avoid using chemicals that
contain benzine, benzene, toluene, xylene, acetone, or similar
solvents.
Do not immerse the probe or use abrasive cleaners.
Dirt may be removed with a soft cloth dampened with a mild
detergent and water solution, or isopropyl alcohol.
Replacement Parts
Refer to the Replaceable Parts section for a list of customer
replacement parts. Due to the sophisticated design of the P6245AD,
there are no user replaceable parts within the probe.
Maintenance
Preparation for Shipment
If the original packaging is unfit for use or not available, use the
following packaging guidelines:
1. Use a corrugated cardboard shipping carton having inside
dimensions at least one inch greater than the probe dimensions.
The box should have a carton test strength of at least 200 pounds.
2. Put the probe into a plastic bag or wrap to protect it from
dampness.
3. Place the probe into the box and stabilize it with light packing
material.
4. Seal the carton with shipping tape.
P6245AD Instruction Manual
4–15
Troubleshooting
This troubleshooting documentation details isolation to either the
probe or the TEKPROBE oscilloscope.
To troubleshoot the P6245AD, the probe must be attached to an
operating TEKPROBE interface oscilloscope with the top cover of
the compensation box removed. Refer to page 4–12 for instructions
on opening the compensation box.
The host instrument should be set to the following settings:
H50 W termination at instrument.
HDC coupling
CAUTION.
Observe caution when probing in the compensation
box. Operating voltages will be present. Be careful not to touch
or ground energized components.
Work at a Level 1 ESD workstation when performing troubleshooting. The compensation box contains static sensitive devices.
4–16
P6245AD Instruction Manual
Troubleshooting
+5
(Red)
Ground
(Black)
–5
(White)
Offset
(Blue)
Offset
–5
Data
Clock
+5
Figure 4–9: Compensation Box Test Point Locations
Refer to Table 4–2 for troubleshooting proceedures, and Figure 4–9
for troubleshooting test points.
Table 4–2: Troubleshooting Guide
SymptomChecksResultAction
No Signal OutCheck known signal
Go to Probe Power
Distorted or
nonlinear signal
Instrument set to
50 W termination?
No signal.
Probe power OK.
Continue checks
Turn in probe.
NoSet termination to
50 W, or install a
feedthrough
termination at the
instrument input.
YesContinue
Distorted or
nonlinear signal
Signal within linear
dynamic range? See
page 2–1.
NoSet channel’s vertical
offset to match signal
characteristic.
P6245AD Instruction Manual
4–17
Troubleshooting
Table 4–2: Troubleshooting Guide (Cont.)
SymptomActionResultChecks
No Offset Adjust
(Signal present)
Probe PowerCheck the power
Go to Probe PowerProbe power OKContinue checks
Check variation of
offset input from host
instrument. See
Figure 4–9. Signal
should vary between
+1 V and –1V.
test points in the
compensation box.
See Figure 4–9.
Offset input OK
Offset input bad
Power OKContinue checks.
Turn in probe.
Check TEKPROBE
interface pins on the
compensation box.
See page 4–11.
Check TEKPROBE
interface on host
instrument. (Try an
adjacent channel.)
Repair host
instrument
4–18
Power badCheck TEKPROBE
interface pins on the
compensation box.
See page 4–11.
Check TEKPROBE
interface on host
instrument. (Try an
adjacent channel.)
Repair host
instrument
P6245AD Instruction Manual
Replaceable Parts
Replaceable Parts
This section contains a list of the replaceable parts for the P6245AD.
Use this list to identify and order replacement parts.
Parts Ordering Information
Replacement parts are available from or through your local
Tektronix, Inc. service center or representative.
Changes to Tektronix instruments are sometimes made to accommodate improved components as they become available and to give you
the benefit of the latest circuit improvements. Therefore, when
ordering parts, it is important to include the following information in
your order:
HPart number
HInstrument type or model number
HInstrument serial number
HInstrument modification number, if applicable
If a part you order has been replaced with a different or improved
part, your local Tektronix service center or representative will
contact you concerning any change in the part number .
P6245AD Instruction Manual
5–1
Replaceable Parts
Using the Replaceable Parts List
The tabular information in the Replaceable Parts List is arranged for
quick retrieval. Understanding the structure and features of the list
will help you find the all the information you need for ordering
replacement parts.
Item Names
In the Replaceable Parts List, an Item Name is separated from the
description by a colon (:). Because of space limitations, an Item
Name may sometimes appear as incomplete. For further Item Name
identification, U.S. Federal Cataloging Handbook H6-1 can be used
where possible.
Indentation System
This parts list is indented to show the relationship between items.
The following example is of the indentation system used in the
Description column:
Detail Part of Assembly and/or Component
Attaching parts for Detail Part
(END ATTACHING PARTS)
Parts of Detail Part
Attaching parts for Parts of Detail Part
(END ATTACHING PARTS)
Attaching parts always appear at the same indentation as the item it
mounts, while the detail parts are indented to the right. Indented
items are part of, and included with, the next higher indentation.
Attaching parts must be purchased separately, unless otherwise
specified.
Abbreviations
5–2
Abbreviations conform to American National Standards Institute
(ANSI) standard Y1.1