LeCroy AP034 User manual

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REVISION D — JANUARY 2000

Warranty
LeCroy warrants this oscilloscope accessory for normal use and operation within
specifications for a period of three years from the date of shipment. Calibration after each 12
month interval is recommended to ensure performance to specification. Spare parts,
replacement parts and repairs are warranted for 90 days. The instrument’s firmware has
been thoroughly tested and thought to be functional, but is supplied without warranty of any
kind covering detailed performance.
In exercising its warranty, LeCroy will repair or, at its option, replace any assembly returned
within its warranty period to the Customer Service Department or an authorized service
center. However, this will be done only if the product is determined by LeCroy’s examination
to be defective because of workmanship or materials, and the defect is not caused by misuse,
neglect, accident, abnormal conditions of operation, or damage resulting from attempted
repair or modifications by a non-authorized service facility.
The customer will be responsible for the transportation and insurance charges for the return of
products to the service facility. LeCroy will return all products under warranty with
transportation prepaid.
This warranty replaces all other warranties, expressed or implied, including but not limited to
any implied warranty of merchantability, fitness, or adequacy for any particular purposes or
use. LeCroy shall not be liable for any special, incidental, or consequential damages, whether
in contract or otherwise.
Corporate Headquarters
700 Chestnut Ridge Road
Chestnut Ridge, NY 10977-6499
Tel: [phone], Fax: [phone]
Internet: www.lecroy.com
Copyright 2000, LeCroy Corporation. All rights reserved. Contents of this publication may not
be reproduced in any form without written permission of LeCroy Corporation.
LeCroy, Easywave, SMART Trigger, PowerMeasure, and ProBus are registered trademarks
of LeCroy Corporation.
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Table of Contents
Overview
Description .................................................................................................................................. 1-1
Applications ................................................................................................................................. 1-1
Conventions used in this Manual ................................................................................................ 1-2
Safety Information
Operator Safety ........................................................................................................................... 2-1
Operation
Connecting the Probe to the Test Instrument ............................................................................. 3-1
Connecting the Probe to the Test Circuit......................................................................................3-1
Probe Input Loading .................................................................................................................... 3-4
Grounding the Probe ................................................................................................................... 3-4
Selecting the Proper Range ........................................................................................................ 3-6
Operation with LeCroy Oscilloscopes ......................................................................................... 3-7
AP034 Use with the ADPPS Power Supply...................................................................................3-8
Adding Offset ............................................................................................................................ 3-10
Autobalance .............................................................................................................................. 3-11
Designing Test Fixtures for the AP033 Probe ........................................................................... 3-12
Reference Information
Differential Mode and Common Mode ........................................................................................ 4-1
Differential Mode Range and Common Mode Range...................................................................4-1
Common Mode Rejection Ratio................................................................................................... 4-2
Care and Maintenance
Cleaning ...................................................................................................................................... 5-1
Calibration Interval ...................................................................................................................... 5-1
Service Strategy .......................................................................................................................... 5-1
Troubleshooting .......................................................................................................................... 5-1
Trace Off Scale................................................................................................................5-1

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Incorrect Frequency Response........................................................................................5-2
DC Errors.........................................................................................................................5-3
Poor Common Mode Rejection.......................................................................................5-3
Returning a Defective Probe ....................................................................................................... 5-4
Replacement Parts ...................................................................................................................... 5-5
Matching Procedure for ÷10 Plug-On External Attenuator .......................................................... 5-8
Equipment Required .....................................................................................................................5-8
Procedure......................................................................................................................................5-9
Performance Verification
Test Equipment Required .............................................................................................................6-1
Preliminary Procedure...................................................................................................................6-3
Procedure......................................................................................................................................6-3
Check Gain Accuracy.......................................................................................................6-4
Check High Frequency CMRR.........................................................................................6-5
Check Low Frequency CMRR..........................................................................................6-8
Performance Verification Test Record........................................................................................6-11
Adjustment Procedure
Introduction .................................................................................................................................. 7-1
Test Equipment Required .............................................................................................................7-2
Preliminary Procedure...................................................................................................................7-4
Procedure......................................................................................................................................7-7
Adjust Coarse DC Balance (R226) ..................................................................................7-7
Adjust Fine DC Balance (R304).......................................................................................7-8
Adjust Low Frequency CMRR (R7)..................................................................................7-9
Adjust Offset (R330) ......................................................................................................7-11
Adjust Gain (R322C)......................................................................................................7-13
Adjust Final Attenuator Compensation (C17) ................................................................7-14
Adjust Final Attenuator CMRR (C18A)...........................................................................7-15
Assemble Probe and Amplifier.......................................................................................7-16
Attenuator Matching and Final Check............................................................................7-17

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Specifications
Nominal Characteristics .............................................................................................................. 8-1
Warranted Electrical Characteristics ........................................................................................... 8-2
Typical Electrical Characteristics ................................................................................................ 8-3
General Characteristics ............................................................................................................... 8-5
Compliance and Certifications .................................................................................................... 8-6
Operator Safety.............................................................................................................................8-6
Standard Accessories ................................................................................................................. 8-7
Optional Accessories .................................................................................................................. 8-7
Oscilloscope Software Compatibility ........................................................................................... 8-7
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DESCRIPTION
The AP034 is a wide-band, active differential probe. The probe
features low noise, low input capacitance, high common mode
rejection, and Field Effect Transistor (FET) buffered inputs in the
probe head. The user-selectable offset gives the probe the
flexibility to measure a large range of signal types. Plug-on
attenuators and AC coupling accessories further extend the
application range. Included interconnect accessories allow
connection to surface mount and through-hole components with
minimal signal degradation. The input receptacles in the probe
head are compatible with standard 0.025 in. (0.635 mm) square
pins, which provide a convenient, low-cost method of creating
device characterization test fixtures.
The probe is powered directly from a LeCroy oscilloscope
through the ProBus interface. The ProBus interface also allows
local control of the probe through the oscilloscope user interface
and remote control through the interface buses, (GPIB, RS-232).
The optional ADPPS power supply allows the AP034 to be used
with other instruments such as spectrum analyzers, network
analyzers, and oscilloscopes without ProBus interface.
APPLICATIONS
The AP034 Active Differential Probe is ideal for acquiring high-
speed differential signals such as those found in disk drive read
channels, differential LAN, video, etc. The probe can be used
with spectrum analyzers to acquire signals in some RF systems
(for example, balanced IF mixers in hand-held cellular
telephones). The high impedance characteristics of both inputs
allow you to use the probe as an FET probe to make single-
ended measurements in digital systems without introducing a
ground loop, as a conventional FET probe would.

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CONVENTIONS USED IN THIS MANUAL
The following conventions may appear in this manual:
Note
A Note contains general information relating to
the use of the product.
Caution
A Caution contains information that should to be
followed to avoid possible damage to the
instrument or the device under test.
WARNING
A Warning alerts you to potential injury to
yourself. Failing to adhere to the statement in a
WARNING message could result in bodily injury.
The following symbol may appear on the product:
This symbol refers you to additional information contained in this
manual. The corresponding information in the manual is denoted
with the same symbol.
CAT I Overvoltage Installation Category per EN 61010-1
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OPERATOR SAFETY
The AP034 Active Differential Probe is intended to be used only
with instruments that are connected to earth ground through the
input BNC connector. When you are using the probe with an
ADPPS Power Supply Adapter, make sure the adapter is
connected to a BNC connector that is grounded by the test
instrument before connecting the probe inputs to the test circuit.
Do not use the probe in wet or explosive atmospheres. Remove
any contamination from the probe housing before connecting the
probe inputs to any circuit. Make sure that the surface of the
probe head is completely dry before connecting the inputs.
Use of the probe, and/or the instrument it is connected to, in a
manner other than that specified may impair the protection
mechanisms.
Do not use the probe if any part is damaged. All maintenance
should be referred to qualified service personnel.
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