Tektronix P7330 Service Manual

Service Manual

P7330 3.5 GHz Differential Probe

071-1057-00

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

*P071105700*

071105700

Copyright © Tektronix, Inc. All rights reserved. Licensed software products are owned by Tektronix or its suppliers and are protected by United States copyright laws and international treaty provisions.

Use, duplication, or disclosure by the Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of the Rights in T echnical Data and Computer Software clause at DFARS 252.227-7013, or subparagraphs (c)(1) and (2) of the Commercial Computer Software – Restricted Rights clause at F AR 52.227-19, as applicable.

T ektronix 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.

T ektronix, Inc., P.O. Box 500, Beaverton, OR 97077 TEKTRONIX, TEK, T ekConnect, and KlipChip are registered trademarks of Tektronix, Inc.

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.

Only qualified personnel should perform service procedures.

Do Not Service Alone. Do not perform internal service or adjustments of this product unless another person capable of rendering first aid and resuscitation is present.

While using this product, you may need to access other parts of the system. Read the General Safety Summary in other system manuals for warnings and cautions related to operating the system.

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. 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 apply a potential to any terminal, including the common terminal, that exceeds the maximum rating of that terminal.

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 . Provide Proper Ventilation. Refer to the manual’s installation instructions for

details on installing the product so it has proper ventilation.

P7330 3.5 GHz Differential Probe Service Manual

General Safety Summary

Symbols and Terms

T erms 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 practices that could result in damage to this product or other property.

T erms 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 including the product. Symbols on the Product. The following symbols may appear on the product:

CAUTION

Refer to Manual

WARNING

High Voltage

Double

Insulated

Protective Ground

(Earth) Terminal

Not suitable for

connection to

the public telecom-

munications network

P7330 3.5 GHz Differential Probe Service Manual

Preface

Manual Structure

Contacting Tektronix

Phone 1-800-833-9200*

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

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

Technical support Email: support@tektronix.com

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.

P7330 3.5 GHz Differential Probe Service Manual

Description

This document describes the Performance Verification and Adjustment Proce- dures for the P7330 Probe. There are no user-replaceable parts inside the probe.

If the probe fails the performance verification procedure, and adjusting the probe cannot compensate for the failure, contact your Tektronix service center.

Performance Verification

Use the performance verification procedures to verify the warranted specifications of the P7330 probe. The recommended calibration interval is one year. No software is required to complete a performance verification of the probe.

The performance verification procedures check the following specifications:

Output zero DC attenuation accuracy Rise time

Adjustments

The P7330 probe has two electronically-adjusted controls that do not need adjusting unless a performance verification yields a specification that is out of tolerance.

If you are making adjustments to the probe, you need the TekConnect Adjustment Software for the P7330 Probe. Refer to Equipment Setup in the Adjustment Procedures for instructions on finding and loading the adjustment software on your instrument.

The adjustment procedures describe the following adjustments for the probe:

Offset zero

DC CMRR

Offset gain

P7330 3.5 GHz Differential Probe Service Manual

Description

Equipment Required

Refer to Table 1 for the equipment required to perform the service procedures.

T able 1: Equipment required for performance verification and adjustment procedures

Item description Performance requirement Recommended example

T ekConnect adjustment software

Sampling Oscilloscope ≥12.5 GHz bandwidth T ektronix TDS8000 Sampling head, with extension cable ≥12.5 GHz bandwidth Tektronix 80E0X with 012-1568-00 cable Oscilloscope T ekConnect Interface T ektronix TDS7404 T ekConnect calibration adapter T ekConnect Interface 067-0422-00 Calibration Step Generator 250 mV step, ≤30ps rise time 067-1338-0X Probe Positioner Three-axis adjustable Tektronix PPM203B Probe Calibration Fixture See page 5 067-0419-00 Adapter TekConnect-to-SMA TCA-SMA DC Power Supply 1 VDC at 1 mA T ektronix PS280 DMM (2) with leads 0.05% accuracy, 0.1mV resolution Fluke 87 or equivalent Feedthrough T ermination 50W ±0.05 BNC-to-BNC coaxial cable 50W coaxial cable 012-0057-01 Coaxial cable Male-to-Male SMA 012-0649-00 Adapter SMA Male-to-Male 015-101 1-00 Adapter SMA Female-to-Female 015-1012-00 Adapter SMA Male-to-BNC Female 015-0554-00 Adapter BNC Female-to-Dual Banana 103-0090-00 Adapter Y -lead adapter 196-3468-00 Adapter Square pin 016-1884-00 Adapters (2) KlipChip adapter 206-0364-00 SMA torque wrench 5/16-in, 7 in-lb. SMA adapter wrench 7/32-in

Required for adjustment procedures only

P7330 Probe Optional Applications for Windows-Based

Oscilloscopes CD

011-0129-00

Special Adapters Required

Some of the adapters listed in Table 1 are custom-made and available only from Tektronix. The adapters are described on the following pages.

P7330 3.5 GHz Differential Probe Service Manual

Description

TekConnect-to-SMA

Adapter

TekConnect Interface

Calibration Adapter

The TekConnect-to-SMA Adapter, Tektronix part number TCA-SMA, allows signals from an SMA cable or probe to be connected to a TekConnect input. See Figure 1. Connect and disconnect the adapter the same way as you do the P7330 Probe.

Figure 1: TekConnect-to-SMA adapter

The TekConnect Interface Calibration Adapter, Tektronix part number 067-0422-00, connects between the host instrument and the probe under test, and provides connectors for probe signal and offset voltage measurements. See Figure 2.

Figure 2: TekConnect Interface Calibration Adapter

When the adapter is connected to the oscilloscope, the adapter is identified as a valid calibration device. However, additional power supplies necessary to power the probe are not enabled until a TekConnect probe is connected to the adapter and identified by the oscilloscope. When a probe is detected through the adapter, the Volts/div readout on the oscilloscope displays ##.

P7330 3.5 GHz Differential Probe Service Manual

Description

Refer to Table 2 for features of the calibration adapter.

T able 2: TekConnect Interface Calibration Adapter features

Feature Description

Offset switch

GND

Latch button

Latch

VAR

Offset voltage output

Signal out

Latch button. The spring-loaded latch mechanically retains the adapter to the oscilloscope. To

release the adapter, grasp the adapter housing, depress the latch button, and pull the adapter straight out of the oscilloscope.

Offset output select switch. The offset output switch selects between ground and the offset

voltage level from the oscilloscope. Leave the switch in the ground position for the performance verification procedures. Move the switch to the variable position for the adjustment procedures.

Offset voltage. The offset voltage of the probe is accessed through the BNC connector.

Measure the offset voltage using a DVM, BNC coaxial cable, and BNC-to-dual-banana jack.

Signal out. The SMA connector on the rear of the box allows for direct monitoring of the probe

signal.

P7330 3.5 GHz Differential Probe Service Manual

Description

Probe Calibration Fixture

Some of these procedures use a probe calibration fixture, Tektronix part number 067-0419-XX.

The calibration fixture provides a means to test the probe for both common mode and differential mode measurements. SMA connectors allow stimulus signals to connect to the fixture and are located on the front and back of the fixture. The fixture is designed to be used with a probe positioner, such as a Tektronix PPM203B.

Figure 3: Probe Calibration Fixture

To use the Probe Calibration Fixture, do the following:

1. Connect the fixture to the test circuit using an SMA cable.

2. Connect the 50W terminator included with the fixture to the unused SMA

connector.

3. Insert and secure the probe in a probe positioner.

4. Position the probe over the fixture, using either the positioner coarse

adjustment or otherwise manipulating the positioner arm in place.

5. Using the fine position and/or pressure adjust, maneuver the probe so that

the pins contact the CM or DM test points, depending on which test you are performing. (See Figure 4 on page 6.)

P7330 3.5 GHz Differential Probe Service Manual

Description

Common mode (CM)

Differential mode (DM)

Figure 4: Probe Calibration Fixture test points

6. Verify that contact is made on both pins. (You may need to readjust the fine

position and/or pressure adjustment to make positive contact with the test points.)

7. Proceed with the instructions according to your specific test .

P7330 3.5 GHz Differential Probe Service Manual

Theory of Operation

Description

Refer to Figure 5 as you read the following information. There are three adjustments in the P7330 adjustment procedure: Offset Zero, DC

CMRR, and Offset Gain. (The CMRR adjustment is not shown in Figure 5.) These adjustments are made using digitally controlled potentiometers that are controlled by a two–wire serial interface from the host oscilloscope. Because the adjustments are digitally controlled, the probe does not need to be disassembled as part of the adjustment procedure. The software application provides the control needed to make the adjustments to the probe.

Figure 5: P7330 simplified schematic diagram

The offset signal from the oscilloscope extends the dynamic range of the P7330 probe by compensating for some of the DC voltage that may be part of the signal applied to the probe. Compensation is accomplished by summing the offset signal with the probe input signal at the probe input attenuator, as shown in Figure 5. The host oscilloscope supplies the offset signal (with a range of ±1 volt) to the offset amplifier in the probe. Since the offset scale factor of the

P7330 3.5 GHz Differential Probe Service Manual

Description

P7330 probe is the same as the input scale factor, the effective offset signal range is also ±1 volt.

The Offset Zero adjustment is used to null out any amplifier voltage offsets in the offset signal path. With no input signal at the probe input and no offset signal from the host oscilloscope, the Offset Zero is adjusted to produce 0.0000 V at the probe output. Since the P7330 probe is designed to operate into a host oscilloscope with a 50 ohm load, a precision 50 ohm feed thru terminator is used in the adjustment procedure.

The DC CMRR adjustment is used to optimize the common-mode rejection performance of the probe tip amplifier to DC signals. The AC CMRR performance of the P7330 probe is not adjustable, but is set by the probe tip amplifier design and manufacturing process.

The Offset Gain adjustment is used to adjust the offset amplifier gain for a precise 5X scale factor. Since the P7330 input signal scale factor has also been designed with a 5X scale factor, the Offset Gain is adjusted to null out the difference between a DC input signal and an offset signal from the host oscilloscope.

P7330 3.5 GHz Differential Probe Service Manual

Performance Verification

Use the following procedures to verify specifications of the P7330 probe. Before beginning these procedures, refer to page 16 and photocopy the test record, and use it to record the performance test results. The recommended calibration interval is one year.

No software is required to do a performance verification of the P7330 probe. These procedures test the following specifications:

Output offset voltage

DC gain accuracy

Rise time

Equipment Setup

Use this procedure to set up the equipment to test the probe.

1. Connect the probe calibration adapter to the oscilloscope.

2. Connect the probe to the probe calibration adapter.

3. Turn on the oscilloscope and enable the channel that the probe calibration

adapter is connected to.

4. Allow 30 minutes for the equipment to warm up.

P7330 3.5 GHz Differential Probe Service Manual

Performance Verification

Output Offset Voltage

1. Connect the equipment as shown in Figure 6.

TDS7404 Oscilloscope

BNC Cable

terminator

BNC-SMA adapter

Set offset switch to GND

KlipChip adapters

T ekConnect calibration adapter Tektronix P/N 067-0422-00

Y-lead adapter

P7330 Probe

KlipChip adapters

connected

together

Square pin adapter

multimeter

BNC-to-Dual

Banana adapter

Digital

50W Precision

Figure 6: Setup for the output offset voltage test

2. Set the offset switch on the calibration adapter to GND.

NOTE. Leave the offset switch in the ground position for all of the performance verification checks.

DC Gain Accuracy

3. Set the multimeter to read DC volts.

4. Verify that the output voltage is 0 V,

±10 mV.

5. Record the results on the test record.

1. Connect the probe to the power supplies as shown in Figure 7 on page 11.

Monitor the source voltage with one of the DMMs (DMM #1 in Figure 7).

2. Set the voltage on each power supply to approximately +0.25 V, to set a

source voltage of about +0.5 V (+0.5 V differential mode, 0 V common mode). Record this source voltage as V

P7330 3.5 GHz Differential Probe Service Manual

Digital multimeter

BNC-to-Dual

Banana Adapter

Performance Verification

TDS7404 Oscilloscope

Set offset switch to GND

50W Precision

terminator

BNC-SMA

adapter

TekConnect calibration adapter

P7330

Probe

BNC cable

Power supply

–+

KlipChip

adapters

Black (–)

Square pin adapter

Digital multimeter

Power supply

–+

Red (+)

Y-lead adapter

Figure 7: DC Gain Accuracy setup

3. Record the output voltage (on DMM #2) as V

out

4. Disconnect and reverse the red and black leads from the probe to the power

supplies. Record the actual voltage (measured on DMM #1) as V

5. Record the output voltage (on DMM #2) as V

out

6. Calculate the gain and % error as follows:

gain

Vout1–Vout2

Vin1–Vin2

Observe polarities when calculating; the negative values of Vin2 and V will yield positive numbers. Example:

gain

0.1007–(–0.1012)

0.2019

0.2017

7. Verify that the gain is 0.2, ± 2%.

8. Record the calculated gain on the test record.

P7330 3.5 GHz Differential Probe Service Manual

0.498–(–0.503)

1.001

%error

measured gain–0.2

0.2

0.2017–0.2

0.2

0.0017

0.2

0.85%

100%

out

Performance Verification

Rise Time

This procedure verifies that the probe meets rise time specifications. Two rise times are measured; the test system, and the test system with the probe included. The probe rise time is calculated using the two measurements.

1. Connect the test equipment as shown in Figure 8.

CAUTION. Use care when working with SMA connectors: support equipment to avoid mechanical strain on the connectors, and use a torque wrench when tightening connections.

TDS7404 Oscilloscope

Set offset switch to GND

Sampling head extender cable

80E0X

SMA

M-to-M

adapter

CSA8000/TDS8000

TekConnect calibration adapter

TekConnect-toSMA adapter

Generator remote head

Internal clock output

Calibration

step generator

Trigger input

SMA Cable

Figure 8: Test system rise time setup

2. Set the oscilloscope trigger to internal clock.

3. Select the channel you have connected to on the 80E0X sampling head, and

then set the oscilloscope vertical scale to 50 mV/div.

P7330 3.5 GHz Differential Probe Service Manual

Performance Verification

NOTE. The output of the step generator rises from a –250 mV level to ground.

4. Adjust the oscilloscope horizontal and vertical position controls to display a

signal similar to that shown in Figure 8.

5. Set the oscilloscope horizontal scale to 50 ps/div, and center the waveform.

6. Use the oscilloscope measurement capability to display rise time. Increase

the stability of the pulse edge measurement by using averaging, if available. Rise time is determined from the 10% and 90% amplitude points on the waveform. Record the rise time as t

The following steps instruct you to assemble the test setup that includes the probe, as shown in Figure 9. The system and probe rise time (t measure in step 17 is used to calculate the probe rise time (t

) that you

s+p

) in step 18.

7. Set the step generator control switch to standby.

8. Remove the TekConnect-SMA adapter from the test setup.

9. Connect the probe to the TekConnect calibration adapter.

10. Connect the probe cal fixture to the step generator remote head and the

terminator to the other input of the probe cal fixture.

11. Secure the probe head in the probe positioner. The test setup should now be connected as shown in Figure 9 on page 14.

P7330 3.5 GHz Differential Probe Service Manual

Performance Verification

TDS7404 Oscilloscope

Set offset switch to GND

Sampling head extender cable

80E0X

SMA

M-to-M

adapter

CSA8000/TDS8000

T ekConnect calibration adapter

P7330 Probe

SMA cable

Internal clock output

Generator

remote head

Probe cal fixture 067-0419-00

Calibration

step generator

Trigger

input

Figure 9: Test system rise time setup with probe

12. Set the step generator control switch to on.

13. On the TDS8000, expand the horizontal scale to help locate the step edge in

step 14, then adjust horizontal range to 500 ps/div while maintaining the edge view. For a more stable measurement display, turn averaging on.

14. Using the probe positioner, probe the DM test points on the probe calibration

fixture. Compare your display to Figure 10 on page 15 to verify that you have a valid connection with both pins.

P7330 3.5 GHz Differential Probe Service Manual

Performance Verification

500 ps/div

20% Gain difference

Both pins in contact

(–) pin not making contact

Figure 10: Verifying both probe pins are contacting the DM test points

15. Adjust the oscilloscope vertical scale to 10 mV/div, averaging on.

16. Adjust the oscilloscope horizontal positioning to place the rising edge of the

signal so that it crosses the second vertical and center horizontal graticule lines.

17. Use the oscilloscope measurement capability to display rise time. Rise time

is determined from the 10% and 90% amplitude points on the waveform. Record the rise time as t

s+p.

18. Calculate the probe rise time using the following formula:

tp+

(s)p)

19. Record the calculated probe rise time on the test record.

P7330 3.5 GHz Differential Probe Service Manual

Performance Verification

T est record

Probe Model: Serial Number: Certificate Number: T emperature: RH %: Date of Calibration: Technician:

Mini-

Performance test

Output offset voltage DC gain accuracy – 2 % ________ ________ + 2 % Rise time N/A ________ ________ ≤140 ps

mum

– 10 mV ________ ________ + 10 mV

Incoming

Outgoing

Maximum

P7330 3.5 GHz Differential Probe Service Manual

Adjustment Procedures

These instructions are for personnel who are familiar with servicing the product. If you need further details for disassembling or reassembling the product, refer to the appropriate product manual. Contact your nearest Tektronix, Inc., Service Center or Tektronix Factory Service for installation assistance.

CAUTION. To prevent static discharge damage, service the product only in a static-free environment. Observe standard handling precautions for static-sensitive devices when servicing the probe. Always wear a grounded wrist strap, grounded foot strap, and static resistant apparel when servicing the probe.

Equipment Setup

Use this procedure to set up the equipment to adjust the probe.

1. Power on the oscilloscope, and enable the channel you intend to use.

2. Connect the probe calibration adapter to the oscilloscope.

3. Connect the probe to the probe calibration adapter.

4. Verify that the Volts/div readout on the oscilloscope channel displays ##

(the oscilloscope recognizes the probe through the adapter).

5. Set the multimeters to read DC volts.

6. Allow 30 minutes for the equipment to warm up.

7. While the equipment is warming, verify that the application has been loaded

onto the oscilloscope:

a. Minimize the scope application window by going to File→Minimize. b. Go to: Start→Programs→Tektronix→TekConnect Adjust c. If the application is not loaded on the oscilloscope, get the application:

Retreive the application CD that came with the oscilloscope, insert the CD in the drive, select Start→Run, and then enter D:\setup.exe

Or, download the application from the Tektronix website at: www.tektronix.com/Software and Drivers/Accessories

8. When the application starts, the display appears as shown in Figure 11.

P7330 3.5 GHz Differential Probe Service Manual

Adjustment Procedures

Application Setup

Figure 11: TekConnect probe adjustment application

1. Make the following selections: a. Select P7330 in the Probe Type to Adjust list. b. In the Channel to Use list, select the oscilloscope channel that the

adapter is connected to.

c. Select Adjustment in the Task to Perform list.

2. Click Continue.

3. The P7330 Probe Adjustments Dialog Box appears. See Figure 13 on

page 20.

NOTE. An error message appears if one of the following conditions exists:

A probe is not connected to the adapter.

A probe model other than a P7330 is connected to the adapter.

The P7330 connected to the adapter is defective (unable to properly communicate with the adapter).

P7330 3.5 GHz Differential Probe Service Manual

Offset Zero

Adjustment Procedures

If an error message appears, click OK, correct the condition that caused the error message, and then click Continue.

4. Proceed to the Offset Zero procedure.

NOTE. To avoid corrupted test results, do not disconnect the probe under test or the probe calibration adapter until you have completed the service procedures. If the probe or adapter are disconnected before completing the procedures, you must reconnect the probe and adapter, and exit and restart the application.

Use this procedure to adjust the probe offset zero.

1. Connect the test equipment as shown in Figure 12.

KlipChip

adapters

connected

together

Set offset switch to GND

P7330 Probe

adapter

Square pin adapter

multimeter

BNC-to-Dual

Banana Adapter

BNC cable

Digital

TDS7404 Oscilloscope

50W Precision

terminator

BNC-SMA adapter

TekConnect Calibration adapter

Figure 12: Setup for offset zero

2. Set the offset switch on the calibration adapter to GND.

3. Click Offset Zero in the application window. See Figure 13 on page 20.

Y-lead

P7330 3.5 GHz Differential Probe Service Manual

Adjustment Procedures

Adjust slider to set offset voltage on DMM to 0.000 V

Click Store Setting after voltage is set

Figure 13: Offset Zero Control in the P7330 Adjustments window

4. Set the offset zero voltage on the DMM to 0.000 V by adjusting the Offset Zero Control. The index value in the Offset Zero Control varies from 0 to 3969, and corresponds to approximately ±20 mV of offset voltage range.

Use one of the following methods to make the adjustment:

Use your finger or the mouse to drag the on-screen slider up or down.

Click or touch the up/down arrow keys above and below the slider. Each click adjusts the offset voltage by about 10 mV.

To increment by ten clicks or about 100 mV, click in the bar above or below the slider.

5. When the offset zero voltage displayed on the voltmeter is 0.000 V ±0.001 V, click Store Setting to save the offset zero voltage level.

In the Summary Info box, the AFTER field updates with the control value from step 5. This is a temporary value until Accept is selected later, after all adjustments have been made.

P7330 3.5 GHz Differential Probe Service Manual

DC CMRR

Adjustment Procedures

NOTE. In the Summary Info box, the After field updates with the control value from step 5. This is a temporary value until Accept is selected later, after all adjustments have been made.

If you select Accept now, the application requests confirmation: If you click Yes, the application exits; if you click No, you are able to make further adjustments. You must complete all adjustments before selecting Accept.

6. Proceed to the DC CMRR procedure.

Use this procedure to adjust the DC common-mode rejection ratio. Due to the interaction of the Offset Zero and DC CMRR adjustments, it may be necessary to repeat the procedure to optimize the adjustments.

1. Click DC Gain Match in the application window. See Figure 14.

Figure 14: DC Gain Match window

P7330 3.5 GHz Differential Probe Service Manual

Adjustment Procedures

2. Connect the test equipment as shown in Figure 15.

3. Set the offset switch on the calibration adapter to GND.

Digital multimeter

KlipChip

adapters

Power supply

–+

Red (+)

P7330

TDS7404 Oscilloscope

Black (–)

Digital multimeter

Square pin adapter

Y-lead adapter

Female BNC-to-male banana adapter

50 W BNC cable

Set offset switch to GND

50 W precision terminator

TekConnect Calibration adapter

Figure 15: DC CMRR setup

4. Set the input voltage on the DC source to 3.0 V, ±10 mV. Record the actual voltage as V

5. Set the Gain Match (CMRR) Control using one of the following methods:

Use your finger or the mouse to drag the on-screen slider up or down.

Click or touch the up/down arrow keys above and below the slider. Each click adjusts the offset voltage by about 10 mV.

To increment by ten clicks or about 100 mV, click in the bar above or below the slider.

6. Adjust the Gain Match control until the value displayed on the voltmeter is

0.0000 V, ±0.0001 V. Click Store Setting to save the offset gain level.

7. Record the output voltage as V

out

8. Set the input voltage on the DC source to approximately –3.0 V. Record the actual voltage as V

P7330 3.5 GHz Differential Probe Service Manual

Adjustment Procedures

9. Record the output voltage as V

10. Calculate the common-mode gain (A

ACM+

Vout1–Vout2

Vin1–Vin2

out

2. ) as follows:

You must include the voltage polarities in this calculation. For example, the value for (V

1 – Vin2) should be about 6 V.

11. Calculate the CMRR in dB as follows:

0.2

|ACM|

20 log

The calculated CMRR should be greater than 60 dB.

12. Reverify that the offset is 0 V, ±3.0 mV:

Repeat steps 1 through 3 in the Output Offset Voltage Performance Verifica- tion procedure on page 10.

If the offset voltage magnitude is greater than 3.0 mV, or if the CMRR is less than 60 dB, disconnect the probe from the test circuit. Repeat the adjustment in the Offset Zero procedure on page 19 to compensate for the adjustment interaction.

In the Summary Info box, the

AFTER field updates with the control value from

step 8. This is a temporary value until Accept is selected later, after all adjustments have been made.

13. Click Store Setting to store the gain level you set in step 6.

14. Proceed to the Offset Gain procedure.

P7330 3.5 GHz Differential Probe Service Manual

Adjustment Procedures

Offset Gain

Use this procedure to adjust the probe offset gain.

1. Connect the test equipment as shown in Figure 16.

Digital

multimeter

BNC-to-Dual

Banana Adapter

BNC cable

50W Precision

terminator

BNC-SMA adapter

Figure 16: Setup for offset gain

TDS7404 Oscilloscope

TekConnect Calibration adapter

Set offset switch to VAR

P7330 Probe

Power supply

–+

Black (–)

Y-lead adapter

PositiveNegative

Power supply

–+

KlipChip adapters

Red (+)

Square pin adapter

Digital

multimeter

2. Set the offset switch on the calibration adapter to VAR.

3. Set the positive DC power supply to +0.35 V, and record the actual voltage

as V

4. Set the negative DC power supply to –0.35 V, and record the actual voltage

as V

5. Click OFFSET GAIN in the application window. See Figure 17 on page 25.

6. Set the Channel Offset Control to –0.700 volts, using one of the following

methods:

Use your finger or the mouse to drag the on-screen slider left or right.

Click or touch the left or right arrow keys to the left and right of the slider. Each click adjusts the offset control voltage by about 1.0 mV.

To increment by ten clicks or about 10 mV, click in the bar to the left and right of the slider.

P7330 3.5 GHz Differential Probe Service Manual

Adjust slider to null the difference between the offset and differential voltages

Click Store Setting after the Offset Gain Control is set

Adjustment Procedures

Adjust slider to set channel offset on DMM to –0.700 V

Figure 17: Offset Gain window

7. Use the offset gain control to null the difference between the probe differen-

tial voltage you set in steps 3 and 4, and the Channel Offset voltage you set in step 6, using one of the following methods:

Use your finger or the mouse to drag the on-screen slider up or down.

Click or touch the up/down arrow keys above and below the slider. Each click adjusts the offset voltage by about 0.5 mV.

To increment by ten clicks or about 5 mV, click in the bar above or below the slider.

8. When the offset gain displayed on the voltmeter is ±1 mV, click Store Setting to update the AFTER field with the new offset gain level.

In the Summary Info box, the AFTER field updates with the control value from step 8. This is a temporary value until Accept is selected.

P7330 3.5 GHz Differential Probe Service Manual

Adjustment Procedures

Verify Operation

9. Click Accept to save all the values that you set in these procedures.

10. Click Yes to update the contents.

This completes the adjustments to the probe.

Do the performance verification procedures for the offset zero and DC attenuation specifications.

End of document

P7330 3.5 GHz Differential Probe Service Manual

Tektronix P7330 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

General Safety Summary

Preface

Manual Structure

Related Documentation

Contacting Tektronix

Description

Performance Verification

Adjustments

Equipment Required

Special Adapters Required

Probe Calibration Fixture

Theory of Operation

Performance Verification

Equipment Setup

Output Offset Voltage

DC Gain Accuracy

Rise Time

Adjustment Procedures

Equipment Setup

Application Setup

Offset Zero

DC CMRR

Offset Gain

Verify Operation