Tektronix P7330 User Manual

User Manual

P7330

3.5 GHz Differential Probe

071-0758-04

Warning

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.

www.tektronix.com

Copyright © Tektronix, Inc. All rights reserved.

Tektronix products are covered by U.S. and foreign patents, issued and
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, SureFoot, and TekConnect are registered trademarks of
Tektronix, Inc., and KlipChip is a trademark of Tektronix, Inc.

WARRANTY

Tektronix warrants that the products that it manufactures and sells will be free from defects
in materials and workmanship for a period of one (1) year from the date of shipment. If a
product proves defective during this warranty 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 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 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
FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR
HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

Preface

This is the User Manual for the P7330 differential probe.
This manual provides operating information, specifications, and a
replaceable parts list.

Related Manuals

If you need to do a performance ve rification or ma ke internal
adjustments to your probe, refer to the P7330 3.5 GHz Differential
Probe Service Manual, Tektronix part number 071-1057-XX. The
manual is a printable pdf file, and is available on both the Tektronix
website and the Optional Applications CD that is included with
Tektronix oscilloscopes featuring the TekConnect interface.

P7330 3.5 GHz Differential Probe User Manual

i

Preface

Contacting Tektronix

Phone [phone]*

Address Tektronix, Inc.

Department or name (if known)
14200 SW Karl Braun Drive
P.O. Box 500
Beaverton, OR 97077
USA

Web site www.tektronix.com

Sales

1-800-833-9200, select option 1*

support

Service

1-800-833-9200, select option 2*

support

Technical

Email: [e-mail]

support

1-800-833-9200, select option 3*

6:00 a.m. -- 5:00 p.m. Pacific time

* This phone number is toll free in North America. After office

hours, please leave a voice mail message.
Outside North America, contact a Tektronix sales office or
distributor; see the Tektronix web site for a list of offices.

ii

P7330 3.5 GHz Differential Probe User Manual

Table of Contents

General Safety Summary iii............................

Preface v............................................

Related Manuals v....................................

Contacting Tektronix vi.................................

Getting Started 1.....................................

TekConnect Interface 1.................................

Functional Check 3....................................

Options 4............................................

Features and Standard Accessories 5......................

Optional Accessories 9.................................

Operating Basics 11...................................

Input Voltage Limits 12.................................

Maximum Input Voltage 12..............................

Common-Mode Signal Range 12..........................

Differential-Mode Signal Range 12........................

Common-Mode Rejection 12.............................

Probing Techniques to Maximize CMRR 13.................

Input Impedance and Probe Loading 14.....................

Probe Grounding 15....................................

Electrical Effects of Accessories 16........................

Reference 17.........................................

Problems with Single-Ended Measurements 17...............

Differential Measurements 17............................

Common-Mode Rejection Ratio 18........................

Assessing CMRR Error 18...............................

Input Impedance Effects on CMRR 19.....................

Extending the Input Leads 19.............................

Extending the Ground Lead 20............................

Appendix A: Specifications 21...........................

Appendix B: User Service 27............................

Appendix C: Replaceable Parts 29.......................

P7330 3.5 GHz Differential Probe User Manual

iii

Table of Contents

List of Figures

Figure 1: P7330 differential probe featuring the

TekConnect Interface 1..............................

Figure 2: Connecting and disconnecting the probe 2..........

Figure 3: Probe functional check connections 3.............

Figure 4: Protect the probe tips with the protective cover 11....

Figure 5: Using the variable spacing adapter 13..............

Figure 6: Using the TwinFoot adapter 13....................

Figure 7: Typical probe input model 14.....................

Figure 8: Probe ground input 15...........................

Figure 9: Typical effects on a signal using probe t ip adapters 16.

Figure 10: Simplified model of a differential amplifier 18......

Figure 11: Twisting the input leads 20......................

Figure 12: Typical common-mode gain 24..................

Figure 13: Typical differential input impedance vs frequency 24.

Figure 14: Probe head and compensation box dimensions 25....

Figure 15: P7330 replaceable parts 31......................

Figure 16: P7330 standard accessories 33...................

Figure 17: P7330 optional accessories 35...................

iv

P7330 3.5 GHz Differential Probe User Manual

General Safety Summary

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.

To Avoid Fire or Personal Injury

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.

The common terminal is at ground potential. Do not connect the
common terminal to elevated voltages.

Do Not Operate Without Covers. Do not operate this product with

covers or panels removed.

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.

Keep Product Surfaces Clean and Dry.

P7330 3.5 GHz Differential Probe User Manual

v

General Safety Summary

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.

CAUTION. Caution statements identify conditions or practice s that
could result in damage to this product or other property.

Terms on the Product. These terms may appear on the product:

DANGER indicates an injury hazard immediately accessible as you
read the marking.

WARNING indicates an injury hazard not immediately accessible as
you read the marking.

CAUTION indicates a hazard to property i ncluding the product.

Symbols on the Product. These symbols may appear on the product:

CAUTION

Refer to Manual

vi

P7330 3.5 GHz Differential Probe User Manual

Getting Started

The P7330 is a high-bandwidth (3.5 GHz) active differential probe
with a miniaturized probe head design. The probe has low circuit
loading, high common-mode rejection, and comes with a variety of
accessories for connecting to surface-mount devices and other
components.

Figure 1: P7330 differential probe featuring the TekConnect Interface

TekConnect Interface

The P7330 probe is powered through a TekConnect Interface
between the probe compensation box and the oscilloscope. The
TekConnect Interface provides a comm unication path through
contact pins on the host instrument. Power, signal, offset, and probe
characteristic data transfer through the interface.

P7330 3.5 GHz Differential Probe User Manual

1

Getting Started

When the probe is connected, the oscilloscope reads EEPROM
information from the probe, identifying the device and allowing the
appropriate power supplies to be turned on. The preamp inputs on the
oscilloscope are ESD protected by remaining grounded until a valid
TekConnect device is detected.

The TekConnect Interface features a spring-loaded latch that
provides audible and tactile confirmation that a reliable connection
has been made to the oscilloscope. Slide the probe into the
TekConnect receptacle on the oscilloscope. The probe snaps into the
oscilloscope when fully engaged. See Figure 2.

To release the probe from the oscilloscope, grasp the compensation
box, press the latch button, and pull out the probe.

Latch button

Figure 2: Connecting and disconnecting the probe

2

P7330 3.5 GHz Differential Probe User 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 3.

Getting Started

Figure 3: Probe functional check connections

1. Connect the probe to the oscilloscope.

2. Set the oscilloscope to display the probe channel.

3. Connect the square pin adapter to the probe tip, and connect the

Y-lead adapter to the square pin adapter. Plug the SMT KlipChips
into the Y-lead adapter.

4. Connect the SMT KlipChips to the PROBE COMPENSATION

connections on the oscilloscope.

5. Adjust the oscilloscope to display a stable calibration waveform.

P7330 3.5 GHz Differential Probe User Manual

3

Getting Started

NOTE. If your instrument supports probe calibration routines, now is
a good time to perform them.

6. Disconnect the probe from the PROBE COMPENSATION

connector and connect the two KlipChips together.

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 500 mV.

9. Adjust the probe offset. The displayed waveform should vary

between approximately +1.0 V and --1.0 V.

Options

The following options are available when ordering the P7330 probe:

H Option D1 -- Calibration Data

H Option C3 -- 3 years Calibration Service

H Option D3 -- 3 years Calibration Data (requires Option C3)

H Option R3 -- 3 years Extended Warranty

4

P7330 3.5 GHz Differential Probe User Manual

Features and Standard Accessories

Table 1 shows the features and standard accessories of the P7330
differential probe.

Table 1: P7330 features and standard accessories

Feature/Accessory Description

TekConnect Interface. The TekConnect Interface provides a

communication path between the probe and the oscilloscope.
Contact pins provide power, signal, offset, and probe characteris­tic data transfer.

The probe snaps into the oscilloscope when fully engaged. To
remove, grasp the compensation box, press the latch button, and
pull the probe out.

Getting Started

Input connections. The plus and minus connections on the
probe tip accept the standard and optional probe accessories.

+

--

Ground

(Some of the accessories connect to the probe tip through the
square pin adapter). The ground lead connects to the probe head
through a slot in the side of the insulated probe housing.

WARNING: Skin penetration hazard. To prevent injury, install the
probe tip cover when the probe is not in use. The probe tips are
extremely sharp to ensure good contact and measurement
integrity.

Probe tip cover. The probe tip cover is shipped on the probe.
The probe tips are extremely sharp to ensure good contact and
measurement integrity. When not using the probe, slide the probe
tip cover over the probe head to prevent damage to the probe tips
and to protect yourself from personal injury.

Tektronix part number: 200-4236-00

Three-inch ground lead (2 ea). Use the ground lead for
connecting the probe ground to the circuit, if needed. The
socketed end of the lead may be connected to accessories, or
fitted onto 0.025-inch square pins.

P7330 3.5 GHz Differential Probe User Manual

Tektronix part number: 196-3469-00 (package of 2)

5

Getting Started

Table 1: P7330 features and standard accessories (Cont.)

Feature/Accessory Description

Variable spacing adapter (4 ea). The variable spacing adapter

fits over the probe tip. Push the adapter onto the probe tip until it
seats against the probe head.

Use the variable spacing adapter to probe any two adjacent leads
or test points spaced between 0.020 and 0.180-inches apart.
Adjust the articulated pins by gently rotating them using a pair of
tweezers.

NOTE: The articulated pins can be bent, but they are fragile. U se
extreme care when bending the pins.

The elastomeric contacts inside the adapter are rated for 50 - 75
insertion cycles with the probe tip. Replace the adapter after

Seated
against

probe head

exceeding these limits to avoid unreliable operation.

Tektronix part number: 016-1885-00 (package of 4)

Seated
against

probe head

Square pin adapter (4 ea). Push the square pin adapter onto the
probe tip until it seats against the probe head. Use the square pin
adapter to connect the probe to other accessories, such as the
Y-lead adapter or TwinFoot adapter. The inputs on the adapter
are spaced 0.100-inches apart.

CAUTION: To avoid damaging the square pin connectors, do not
insert anything larger than a 0.025-inch square pin into the inputs.

The elastomeric contacts inside the adapter are rated for 50 - 75
insertion cycles with the probe tip. Replace the adapter after
exceeding these limits to avoid unreliable operation.

Tektronix part number: 016-1884-00 (package of 4)

6

P7330 3.5 GHz Differential Probe User Manual

Table 1: P7330 features and standard accessories (Cont.)

Feature/Accessory Description

TwinFoot adapter (4 ea). Use the TwinFoot adapter to probe two

adjacent leads on a surface-mount integrated circuit. The
TwinFoot adapter connects to the probe through the square pin
adapter. Flexible fingers adapt to a range of lead spacings. See
Figure 6 on page 13.

Tektronix part number: 016-1785-00 (package of 4)

Y-lead adapter (2 ea). The Y-lead adapter connects to the probe
through the square pin adapter. The socketed ends of the leads
may be connected to the probe tips and accessories, or fitted onto

0.025-inch square pins.

Getting Started

Cable marker bands

Tektronix part number: 196-3468-00 (package of 2)

X-lead adapter (2 ea). The X-lead adapter connects between
accessories fitted with 0.025-inch pins, such as the SMT KlipChip
and Micro KlipChip adapters.

You can use the X-lead adapter with the adapters below to make
connections between the probe tip and your circuit under test.
Be aware of the electrical effects of the added lead length of the
adapters, especially as circuit frequencies increase.

Tektronix part number: 196-3473-XX (package of 1)

SMT KlipChip adapter (2 ea). Use this accessory to probe the
leads on dual-in-line packages (DIP).

Tektronix part number: 206-0364-XX (package of 1)

Cable marker bands (10 ea). Attach matching pairs of the
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.

P7330 3.5 GHz Differential Probe User Manual

Tektronix part number: 016-1315-00 (package of 10)

7

Getting Started

Table 1: P7330 features and standard accessories (Cont.)

Feature/Accessory Description

Plastic accessory box. Use the plastic box to store the probe

accessories when not in use.

Tektronix part number: 006-7164-00

Instrument case. The instrument case protects the probe from
harsh environments and provides room for storing optional
accessories.

Tektronix part number: 016-1879-XX

Calibration certificate. A certificate of traceable calibration is
provided with every instrument shipped.

Accessory reorder sheet.

Use the accessory reorder sheet as a quick guide for ordering
accessories for your probe. The sheet provides photos and part
numbers for identifying your accessories.

Tektronix part number 001-1362-XX

User Manual. Provides instructions for operating and maintaining
the P7330 differential probe

Tektronix part number: 071-0758-XX

Antistatic wrist strap. When using the probe, always work at an
antistatic work station and wear the anti static wrist strap.

Tektronix part number: 006-3415-04

8

P7330 3.5 GHz Differential Probe User Manual

Optional Accessories

Table 2 shows the optional accessories that you can order for t he
P7330 differential probe.

Table 2: Optional accessories

Accessory Description

TekConnect Interface calibration adapter. The calibration

adapter is required when a performance verification or adjustment
is done on the probe. It provides connectors and test points for
internal probe measurements.

Tektronix part number 067-0422-00

Getting Started

Probe calibration fixture. Use the probe calibration fixture to
perform some of the calibration procedures. The calibration fixture
connects to signal sources used to test the probe characteristics.

Tektronix part number 067-0419-XX

IEEE1394 Adapter. The IEEE1394 Adapter allows you to probe
signals on the bus, external to system enclosures, without
disturbing system operation. The adapter maintains a balanced
55 Ω signal path and can be used in both single-ended and
differential modes.

Tektronix part number: 679-5027-00

P7330 3.5 GHz Differential Probe User Manual

9

Getting Started

Table 2: Optional accessories (Cont.)

Accessory Description

Micro KlipChip adapters. Use the adapters to probe the leads

on integrated circuits that are surface-mounted.

Tektronix part number: SMK4 (package of 4)

Calibration software and instructions.

Use the Optional Applications Software CD that is shipped with
host instruments featuring the TekConnect interface. Alternatively,
you can download the software from the Tektronix website, or
order the CD using the part number below.

Tektronix part number: 063-3376-XX

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P7330 3.5 GHz Differential Probe User Manual

Operating Basics

This section discusses operating considerations and probing
techniques. For more detailed information about differential
measurements and common-mode rejection ratio (CMRR), see the
Reference sectiononpage17.

The P7330 probe design is optimized for high bandwidth, low
capacitance applications; it is not a general purpose probe. The probe
head and tips are miniaturized for electrical characteristics and
access to dense circuitry, and must be handled carefully. Rough or
careless use will likely damage the probe.

To avoid damaging the probe tips, minimize your lateral pressure on
the tips. Always probe as straight onto the circuit (pe rpendicular) as
possible. The probe tips are extremely sharp to ensure good contact
and measurement integrity.

WARNING. The sharp probe tips pose a skin penetration hazard. Use
care when handling the probe. To prevent injury and/or probe
damage, install the protective cover over the probe tips when the
probe is not in use (see Figure 4).

Figure 4: Protect the probe tips with the protective cover

P7330 3.5 GHz Differential Probe User Manual

11

Operating Basics

Input Voltage Limits

The P7330 differential probe is designed to probe low-voltage
circuits. Before probing a voltage, take into account the limits for
maximum input voltage, the common-mode signal range, and the
differential-mode signal range. For specific limits, see Specifications
on page 21.

Maximum Input Voltage

The maximum input voltage is the maximum voltage to ground that
the inputs can withstand without damaging the probe input circuitry.

CAUTION. To avoid damaging the inputs of the P7330 differential
probe, do not apply more than ±15 V (DC + peak AC) between each
input and ground.

Common-Mode Signal Range

The common-mode signal range is the maximum voltage that you
can apply to each input, with respect to earth ground, without
saturating the input circuitry of the probe. A common-mode voltage
that exceeds the common-mode signal range may produce an
erroneous output waveform even when the differenti al-mode
specification is met. For Specifications, refer to page 21.

Differential-Mode Signal Range

The differential-mode signal range is the maximum voltage
difference between the plus and minus inputs that the probe can
accept without distorting the signal. The distortion from a voltage
that is too large can result in a clipped or otherwise distorted and
inaccurate measurement. For Specifications, refer to page 21.

Common-Mode Rejection

The common-mode rejection ratio (CMRR) is the ability of a probe
to reject signals that are common to both inputs. More precisely,
CMRR is the ratio of the differential gain to the common-mode gain.
The higher the ratio, the greater the ability to reject common-mode
signals. For additional information about CMRR, see page 18.

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P7330 3.5 GHz Differential Probe User Manual

Probing Techniques to Maximize CMRR

The common-mode rejection of the probe is highest when the probe
is applied directly to the circuit, without using adapters. However,
some probing tasks are made easier using accessories incl uded with
the probe. The accessories shown in Figures 5 and 6 achieve a high
CMRR by minimizing the distance between the probe head and the
signal source.

Operating Basics

Figure 5: Using the variable spacing adapter

TwinFoot adapter

Square pin adapter

Conductive side

Probe

of probe tip

Insulated side of probe tip

Figure 6: Using the TwinFoot adapter

IC leads being probed

P7330 3.5 GHz Differential Probe User Manual

13

Operating Basics

Input Impedance and Probe Loading

When you connect the probe inputs to a circuit, you are introducing a
new resistance, capacitance, and inductance into the circuit. Each
input of the P7330 differential probe has a characteristic input
impedance of 50 kΩ to ground in paral lel with le ss than 0.4 pF. See
Figure 7.

For signals with low source impedance and frequency, the 50 kΩ
input impedance on each input is large enough to prevent the inputs
from loading the signal sources. The greater the source impedances
and the higher the signal frequencies, the more you must take these
factors into account.

Input

+

0.4pF 50kΩ

Ground

--

0.1 pF0.4 pF

Input

50 kΩ

Figure 7: Typical probe i nput model

As the impedance of the signal source on an input increases, the
more the probe loads the source and reduces the signal amplitude.

The frequency of the signal also affects signal measurement. As the
frequency of the signal increases, the input impedance of the probe
decreases. The lower the impedance of the probe relative to that of
the source, the more the probe loads the circuit under test and
reduces the signal amplitude. For a graph of frequency versus input
impedance, refer to Figure 13 on page 24.

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P7330 3.5 GHz Differential Probe User Manual

Probe Grounding

In addition to the plus and minus inputs on the probe head, there is
also a ground (common) input. The ground lead slides into the notch
on the side of the probe. See Figure 8.

+

Operating Basics

-­Ground

Figure 8: Probe ground input

CAUTION. To avoid damaging the circuitry under test, connect the
probe ground (common), if used, to a ground-reference point only.

In most applications, the common-mode impedance to ground is
greater than the differential impedance. Adding the probe ground
lead does not improve the high-frequency performa nce of the
measurement. You can use the probe to take a differential measure­ment regardless of whether or not the ground (common) is con­nected.

There are some applications that may require a ground reference
connection to maintain measurement accuracy. Generally this is
necessary when probing circuits which are fully isolated from
ground, such as battery operated devices.

P7330 3.5 GHz Differential Probe User Manual

15

Operating Basics

Electrical Effects of Accessories

The probe tip accessories included with your probe help connect to
different types of components. While these accessories make
connections easier, be aware that the adapter you choose may affect
the signal you are measuring, depending on a variety of factors,
including signal frequency, source impedance, and lead length.

Use the probe only (without adapters) to optimize step and frequency
response. Using the probe tip adapters adds inductance and
capacitance, which increases step re sponse a nd aberrations, a nd leads
to increased ripples in frequency response. These effects increase as
the source impedance and the measured waveform risetimes
decrease. Refer to page 23 for input capacitance specifications when
using the variable spacing and square pin adapters.

The recommended method for hands-free probing is to use the probe
only (without adapters), with a probe positioner such as a Tektronix
PPM203B. If you need a tip space between 0.020 and 0.180 inches
apart, use the variable spacing adapter and the probe positioner. Use
the square pin adapter for test points or component leads spaced
farther than 0.180 inches apart.

Figure 9 illustrates the typical effects on a given signal using some of
the adapters included with your probe.

Probe only

Variable
spacing
adapter

Square pin
adapter

Figure 9: Typical effects on a si gnal usi ng probe tip adapters

16

P7330 3.5 GHz Differential Probe User Manual

Reference

This section contains important reference information about
differential measurements and how to increase the accuracy of your
measurements.

Problems with Single-Ended Measurements

While suitable in many applications, single-ended measurements can
present problems in the following situations:

H When the signal is not referenced to eart h ground

H When the signal being measured is distorted or changed by

connecting or disconnecting the probe ground refere nce lead

Differential Measurements

Devices designed to make differential mea surements avoid the
problems posed by single-ended systems. These devices include a
variety of differential probes, differential amplifiers, and isolators.

The differential amplifier (Figure 10) is at the heart of any device or
system designed to make differential measurements. Ideally , the
differential amplifier rejects any voltage that is common to the inputs
and amplifies any difference between the inputs. Voltage that is
common to both inputs is often referred to as the Comm on-Mode
Voltage (V
Voltage (V

) and voltage that is different as the Differential-Mode

CM

).

DM

P7330 3.5 GHz Differential Probe User Manual

17

Reference

+

Differential

mode

Common

mode

+

V

DM

+

V

CM

--

Figure 10: Simplified model of a differential amplifier

V

out

Common-Mode Rejection Ratio

In reality, differential amplifiers cannot reject all of the common­mode signal. The ability of a differential amplifier to reject the
common-mode signal is expressed as the Common-Mode Rejection
Ratio (CMRR). The CMRR is the differential-mode gain (A
divided by the common-mode gain (A

). It is expressed either as a

CM

DM

)

ratio or in dB.

A

DM

A

CM

CMRR =

A

DM

dB = 20 log

A

CM

CMRR generally is highest (best) at DC and degrades with
increasing frequency.

Assessing CMRR Error

Figure 12 on page 24 shows the CMRR of the P7330 differential
probe. This derating chart assumes a common-mode signal that is
sinusoidal.

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P7330 3.5 GHz Differential Probe User Manual

Reference

A quick way to assess the magnitude of CMRR error when the
common-mode signal is not sinusoidal is to connect both leads to the
same point in the circuit. The oscilloscope will display only the
common-mode component which is not fully rejected by the probe.
While this technique may not give you entirely accurate measure­ments, it does allow you to determine if the magnitude of the
common-mode error signal is significant.

Input Impedance Effects on CMRR

The lower the input impedance of the probe relative to the source
impedance,thelowertheCMRR.SeeFigure12onpage24.
Significant differences in the source impedance driving the two
inputs will also lower the CMRR.

Extending the Input Leads

At times it may be necessary to extend the probe inputs with wires or
a probe tip adapter. When you do this, you should minimize the lead
lengths to optimize common-mode rejection and twist the input leads
together as shown in Figure 11.

Twisting the input leads together does increase capacitance that may
degrade high-frequency performance. You should take into account
any effects caused by the extended leads when you take a measure­ment.

P7330 3.5 GHz Differential Probe User Manual

19

Reference

Square pin adapter

Figure 11: Twisting the input leads

Extending the Ground Lead

Extending the ground lead will have little, if a ny, affect on your
measurements. In most circuits, the ground path from the differential
source has sufficiently high impedance to damp out any ringing
caused by lead inductance.

20

P7330 3.5 GHz Differential Probe User Manual

Appendix A: Specifications

The specifications in Tables 3 through 6 apply to a P7330 probe
installed on a TDS7404 oscilloscope. The probe must have a
warm-up period of at least 20 minutes and b e in an environment that
does not exceed the limits described in Table 3. Specifications for the
P7330 differential probe fall into three categories: warranted, typic al,
and nominal characteristics.

Warranted Characteristics

Warranted characteristics (Table 3) describe guaranteed performance
within tolerance limits or certain type-tested requirements.
Warranted characteristics that have checks in the Performance
Verification section are marked with the n symbol.

Table 3: Warranted electrical characteristics

Characteristic

n Rise time (probe only)

n DC gain

Description

140 ps (130 ps typical)

0.2 ±2%

n Output offset voltage ±10 mV +20_ Cto+30_ C

(+68_ Fto+86_ F)

±50 mV displayed on screen with
TekConnect interface

Maximum nondestructive input voltage ±15 V(DC + peak AC) between signal and

common of the same channel.

Delay variation (probe-to-probe) 600 ps maximum

Temperature

Operating: 0 to +40_ C

(+32 to +104_ F)

Nonoperating: --55 to +75_ C

(--131 to +167_ F)

1

P7330 3.5 GHz Differential Probe User Manual

21

Appendix A: Specifications

Table 3: Warranted electrical characteristics (Cont.)

Characteristic

Humidity Operating: 0--90% RH, tested at

1

See warning that follows.

Description

+30to+40_ C (+68 to +104_ F)

Nonoperating: 0--90% RH, tested at
+30to+60_ C (+68 to +140_ F)

WARNING. To avoid a burn hazard at high ambient temperatures, do
not touch the probe with bare hands at nonoperating temperatures
above + 70_ C. Allow sufficient time for the probe to cool before
handling

.

T ypical Characteristics

Typical characteristics (Tables 4 and 5) describe typical but not
guaranteed performance.

Table 4: Typi cal el ectrical characteristics

Characteristic Description

Bandwidth (probe only) DC to ≥ 3.5 GHz (-- 3dB)

Differential signal range ±2.0 V

Differential offset range ±1V

Linearity ±1% or less of dynamic range

Common-mode signal range +5 V to --4 V

Common-mode rejection ratio ≥60 dB at DC

22

≥55 dB at 1 MHz
≥45 dB at 30 MHz
≥25 dB at 1 GHz

P7330 3.5 GHz Differential Probe User Manual

Table 4: Typical el ectrical characteristics (Cont.)

Characteristic Description

Delay time 5.53 ns

Appendix A: Specifications

Differential input resistance, DC coupled

100 kΩ ± 2%

Differential input capacitance:

probe only

probe with variable spacing

<0.3 pF @100 MHz

<0.45 pF @100 MHz

adapter (P/N 016-1885-00)

probe with square pin

<0.55 pF @100 MHz

adapter (P/N 016-1884-00)

Common-mode input resistance, DC

50 kΩ ±2% (per side)

coupled

Common-mode input capacitance <0.45 pF @100 MHz (per side)

Input impedance SeeFigure13

Noise, referred to input 35 nV/√Hz @100 MHz

DC Offset Scale Accuracy

ᐔ2.0%

(gain of offset signal path)

DC Offset Drift

150 V/°C or less at output of probe

DC Voltage Measurement Accuracy
(referred to input)

P7330 3.5 GHz Differential Probe User Manual

0.75 mV/°C or less displayed on screen with
TekConnect interface

ᐔ[2% of input + (2% of offset) + 50.0 mV +

40.0 mV]

gain error = ᐔ2% of input voltage

offset gain error =ᐔ2% of effective offset at
probe tip

output zero = ᐔ50 mV effective at probe tip

linearity error = ᐔ1.0% of 4.0 V dynamic
range (40.0 mV)

23

Appendix A: Specifications

Figure 12 shows the typical common-mode gain of the probe. The
CMRR can be approximated by subtracting the common-mode gain
from the --14 dB reference level. For example, --80 dB CM gain
equals +66 dB CMRR.

-- 4 4

-- 5 2

-- 6 0

-- 6 8

Gain dB

-- 7 6

-- 8 4

10 MHz1 MHz 100 MHz

Frequency

1GHz

Figure 12: Typical common-mode gain

The graph in Figure 13 represents simulation results of a first order
model of the probe input.

Impedance (Ω)

100 k

10 k

1k

100

10

1M

Figure 13: Typical differential i nput impedance vs frequency

24

10 M

100 M

Frequency (Hz)

1G

P7330 3.5 GHz Differential Probe User Manual

Appendix A: Specifications

Table 5: Typical m echanical characteristics

Dimensions, control box 91.5 mm × 43.8 mm × 31.8 mm

(3.60 in × 1.725 in × 1.25 in)

Dimensions, probe head 59 mm × 7.7 mm × 5.1 mm

(2.30 in × 0.30 in × 0.20 in)

Dimensions, output cable 1.2m(47in)

Unit weight (probe only) 223g(7.5oz)

7.6 mm

(.300 in)

5.08 mm
(.200 in)

58.42 mm
(2.300 in)

2.54 mm
(.100 in)

31.8 mm

(1.250 in)

63.5 mm

(2.500 in)

Figure 14: Probe head and compensation box dimensions

43.8 mm

(1.725 in)

91.5 mm

(3.600 in)

P7330 3.5 GHz Differential Probe User Manual

25

Appendix A: Specifications

Nominal Characteristics

Nominal characteristics (Table 6) describe guaranteed traits, but the
traits do not have tolerance limits.

Table 6: Nominal electrical characteristics

Input configuration Differential (two inputs, + and -- ), with case

ground

Attenuation 5X

Input coupling DC

Termination

Terminate output into 50 Ω

26

P7330 3.5 GHz Differential Probe User Manual

Appendix B: User Service

This section details the maintenance for the P7330 differential probe.

Inspection and Cleaning

Protect the probe from adverse weather conditions. The probe is not
waterproof.

CAUTION. To prevent damage to the probe, do not expose it to sprays,
liquids, or solvents. Do not use chemical cleaning agents; they may
damage the probe. Avoid using chemicals that contain benzine,
benzene, toluene, xylene, acetone, or similar solvents.

Clean the exterior surfaces of the probe with a dry, lint-free cloth or a
soft-bristle brush. If dirt remains, use a soft cloth or swab dampened
with a 75% isopropyl alcohol solution. A swab is useful for cleaning
narrow spaces on the probe. Do not use abrasive compounds on any
part of the probe.

CAUTION. Avoid getting moisture inside the probe during exterior
cleaning and use only enough solution to dampen the swab or cloth.
Use a 75% isopropyl alcohol solution as a cleanser, and rinse with
deionized water.

Replacement Parts

Refer to the Replaceable Parts section for a list of customer
replacement parts. Due to the sophisticated design of the P7330
differential probe, there are no user replaceable parts within the
probe.

P7330 3.5 GHz Differential Probe User Manual

27

Appendix B: User Service

Performance Verification and Adjustments

If you need to do a performance ve rification or ma ke internal
adjustments to your probe, refer to the P7330 3.5 GHz Differential
Probe Service Manual, Tektronix part number 071-1057-XX. The
manual is a printable pdf file, and is available on both the Tektronix
website and the Optional Applications CD that is included with
Tektronix oscilloscopes featuring the TekConnect interface.

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 an antistatic 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.

28

P7330 3.5 GHz Differential Probe User Manual

Appendix C: Replaceable Parts

This section contains a list of replaceable parts for the P7330
differential probe. 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:

H Part number

H Instrument type or model number

H Instrument serial number

H Instrument 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.

P7330 3.5 GHz Differential Probe User Manual

29

Appendix C: 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 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:

12345 Name&Description
Assembly and/or Component
Attaching parts for Assembly and/or Component

(END ATTACHING PARTS)
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

Abbreviations conform to American National Standards Institute
(ANSI) standard Y1.1

30

P7330 3.5 GHz Differential Probe User Manual

Appendix C: Replaceable Parts

3

1

P7330 3.5 GHz Differential Probe User Manual

2

Figure 15: P7330 replaceable parts

31

Appendix C: Replaceable Parts

Mfr. part no.

Mfr.

code

12345 name & description

Qty

Serial no.

Effective Dscont

part no.

Tektronix

010-0641-04 1 PROBE ASSEMBLY:SERVICE REPLACEMENT, SERIALIZED 80009 010-0641-04

-2 200-4236-00 1 COVER, PR O BE TIP 80009 200-4236-00

Fig. &

index no.

15-1

-3 016-1879-XX 1 CASE,STORAGE:PLASTIC,W/ANTISTAT FOAM TK6108 016-1879-XX

P7330 3.5 GHz Differential Probe User Manual32

Appendix C: Replaceable Parts

7

6

5

4

3

2

10

9

8

1

P7330 3.5 GHz Differential Probe User Manual

Figure 16: P7330 standard accessories

33

Appendix C: Replaceable Parts

Mfr. part no.

Mfr.

code

060D9 196-3468-00

060D9 196-3473-00

TK0623 RTI 8454001829

CORD

071-0758-XX 1 MANUAL,TECH:USER,P7330 80009 071-0758-XX

-10 006-3415-04 1 STRAP,WRIST:3M TYPE 2214, ADJUSTABLE,6 FT COILED

-2 196-3473-00 2 LEAD,PIN JUMPER:DIFF,FEMALE SQ PIN CONNECTOR

TO FEMALE SQ PIN CONNECTOR,23 AWG,3.0 L

-3 196-3469-00 1 LEAD GROUND:GROUND LEAD,PKG OF 2 196-3469-00

-4 016-1785-00 1 ADAPTER: DIFFEREN TIAL PROBE,PKG OF 4 80009 016-1785-00

-5 016-1884-00 1 ACCESSORY KIT:SQUARE PIN ADAPTER,PKG OF 4 060D9 016-1884-00

-6 016-1885-00 1 ACCESSORY KIT:VARIABLE SPACER ADAPTER,PKG OF 4 060D9 016-1885-00

-7 016-1315-00 1 MARKER KIT,ID:CABLE MARKER BAND,2 EA, VAR COLRS 80009 016-1315-00

-8 206-0364-XX 2 TIP,PROBE:MICROCKT TEST,SMT KLIPCHIP 80009 206-0364-XX

-9 006-7164-00 1 BOX,PLASTIC :4.625 X 2.875 X 1.0 80009 006-7164-00

STANDARD ACCESSORIES

12345 name & description

Qty

Serial no.

Effective Dscont

part no.

Tektronix

Fig. &

index no.

BLACK,2.300 L,JACK TIP,PKG OF 2

16-1 196-3468-00 1 LEAD, ELEC:DESCRETE,CPD,2,22 AWG,RED &

P7330 3.5 GHz Differential Probe User Manual34

Appendix C: Replaceable Parts

3

4

1 2

P7330 3.5 GHz Differential Probe User Manual

Figure 17: P7330 optional accessories

35

Appendix C: Replaceable Parts

Mfr. part no.

Mfr.

code

OPTIONAL ACCESSORIES

12345 name & description

Qty

Serial no.

Effective Dscont

part no.

Tektronix

-2 067-0419-00 1 PROBE CALIBR ATION F IXTURE 80009 067-0419-00

-3 679-5027-00 1 CKT BD SU BASSY:1394 ADAPTER 80009 679-5027-00

-4 SMK4 1 TIP,PROBE:MICROCKT TEST,PKG OF 4 80009 SMK4

Fig. &

index no.

17 -1 067-0422-00 1 CALIBRATION FIXTURE ASSY:ECB TO TOP,P7000 SERIES 80009 067-0422-00

P7330 3.5 GHz Differential Probe User Manual36

BEAVERTON, OR 97077-0001

Appendix C: Replaceable Parts

PO BOX 500

CROSS INDEX - MFR. CODE NUMBER TO MANUFACTURER

UNITREK CORPORATION 3000 COLUMBIA HOUSE BLVD, SUITE 120 VANCOUVER, WA 98661

Mfr. code Manufacturer Address City, state, zip code

060D9

26805 M/A COM OMNI SPECTRA INC MICROWAVE CONNECTOR DIV 140 4TH AVE WALTHAM, MA 02254

80009 TEKTRONIX INC 14150 SW KARL BRAUN DR

TK0623 GENERAL TOOL & SUPPLY CO 2705 NW NICOLAI ST PORTLAND, OR 97210

TK2565 VISION PLASTICS INC 26000 SW PARKWAY CENTER DRIVE WILSONVILLE, OR 97070

TK6108 KENT H LANDSBERG CO 27929 SW 95TH, SUITE 101 WILSONVILLE, OR 97070

P7330 3.5 GHz Differential Probe User Manual

37

Appendix C: Replaceable Parts

P7330 3.5 GHz Differential Probe User Manual38