Teledyne Lecroy AP034 Operator's Manual

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Operator’s

Manual

AP034 Active
Differential Probe

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AP034 Active Differential Probe

Operator’s Manual

May 2013

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© 2013 Teledyne LeCroy, Inc. All rights reserved.

Unauthorized duplication of Teledyne LeCroy documentation materials other than for internal sales
and distribution purposes is strictly prohibited. However, clients are encouraged to distribute and
duplicate Teledyne LeCroy documentation for their own internal educational purposes.

WaveSurfer, WaveRunner, and Teledyne LeCroy are registered trademarks of Teledyne LeCroy, Inc.
Windows is a registered trademark of Microsoft Corporation. Other product or brand names are
trademarks or requested trademarks of their respective holders. Information in this publication
supersedes all earlier versions. Specifications are subject to change without notice.

Warranty

Teledyne LeCroy warrants this oscilloscope accessory for normal use and operation within
specification for a period of one year from the date of shipment. Spare parts, replacement parts and
repairs are warranted for 90 days.

In exercising its warranty, Teledyne LeCroy, at its option, will either repair or 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 Teledyne LeCroy’s
examination to be defective due to 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. Teledyne LeCroy will return all products under warranty with
transportation charges 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.
Teledyne LeCroy shall not be liable for any special, incidental, or consequential damages, whether in
contract or otherwise.

922261-00 Rev A
May 2013

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Operator’s Manual

922261-00 Rev A i

Table of Contents

Safety Instructions ............................................................................................... 1

Symbols .................................................................................................................. 1

Precautions ............................................................................................................. 1

Operating Environment .......................................................................................... 2

Overview ............................................................................................................ 3

Description ............................................................................................................. 3

Applications ............................................................................................................ 3

Standard Accessories ............................................................................................. 4

Optional Accessories .............................................................................................. 4

Oscilloscope Software Compatibility...................................................................... 4

Specifications ...................................................................................................... 5

Operation ........................................................................................................... 8

Connecting the Probe to the Test Instrument ....................................................... 8

Connecting the Probe to the Test Circuit ............................................................... 8

Probe Input Loading ............................................................................................. 10

Grounding the Probe ............................................................................................ 10

Selecting the Proper Range .................................................................................. 11

Operation with Teledyne LeCroy Oscilloscopes ................................................... 12

Using AP034 with the APPPS Power Supply ......................................................... 12

Adding Offset........................................................................................................ 14

Autobalance ......................................................................................................... 15

Designing Test Fixtures for the AP034 Probe ....................................................... 15

Maintenance ..................................................................................................... 16

Cleaning ................................................................................................................ 16

Calibration Interval ............................................................................................... 16

Service Strategy .................................................................................................... 16

Troubleshooting ................................................................................................ 17

Returning a Probe ............................................................................................. 19

Replacement Parts ............................................................................................ 20

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AP034 Active Differential Probe

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Matching Procedure for ÷10 Plugs ...................................................................... 22

Equipment Required .............................................................................................22

Procedure .............................................................................................................23

Performance Verification ................................................................................... 25

Test Equipment Required .....................................................................................25

Preliminary Procedure ..........................................................................................27

Procedure .............................................................................................................27

Adjustment Procedure ....................................................................................... 34

Introduction ..........................................................................................................34

Test Equipment Required .....................................................................................35

Preliminary Procedure ..........................................................................................37

Procedure .............................................................................................................38

Reference Information ....................................................................................... 47

Differential Mode and Common Mode ................................................................47

Differential Mode Range and Common Mode Range ..........................................47

Common Mode Rejection Ratio ...........................................................................48

Certifications ........................................................................................................49

Contact Teledyne LeCroy .................................................................................... 52

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Operator’s Manual

922261-00 Rev A 1

Safety Instructions

This section contains instructions that must be observed to keep this oscilloscope accessory
operating in a correct and safe condition. You are required to follow generally accepted safety
procedures in addition to the precautions specified in this section. The overall safety of any system

incorporating this accessory is the responsibility of the assembler of the system.

Symbols

These symbols may appear on the probe body or in this manual to alert you to important safety
considerations.

HIGH VOLTAGE, risk of electric shock.

CAUTION of Potential damage to probe or instrument it is connected to, or
WARNING of potential bodily injury. Attend to the accompanying

information to protect against personal injury or damage. Do not proceed
until conditions are fully understood and met.

ELECTROSTATIC DISCHARGE (ESD) HAZARD. The probe is susceptible to
damage if anti-static measures are not taken.

DOUBLE INSULATION

PROTECTIVE (EARTH) TERMINAL

Precautions

To avoid personal injury, or damage to the probe or test instrument, comply with the following
safety precautions.

Use product only as specified.

Connect and disconnect properly. Connect probe to the measurement instrument before

connecting the test leads to a circuit/signal being tested.

Use only accessories compatible with the probe. Use only accessories that are rated for the
application. Ensure connections between probe input leads and probe accessories are secure
before connecting them to a voltage source.

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AP034 Active Differential Probe

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Do not overload. To avoid electric shock, do not apply any potential that exceeds the maximum
rating of the probe and/or the probe accessory, whichever is less. Observe all terminal ratings of
the instrument before connecting the probe.

Be careful not to damage the insulation surface when making measurements.

Use only within operational environment listed. Do not use in wet or explosive atmospheres.

Keep product surfaces clean and dry. Use indoors only.

Handle with care. Probe accessory tips are sharp. They can puncture skin or cause other bodily
injury if not handled properly.

Keep fingers behind the finger guard of the probe accessories.

Do not operate with suspected failures. Before each use, inspect the probe and accessories for any

damage such as tears or other defects in the probe body, cable jacket, accessories, etc. If any part
is damaged, cease operation immediately and sequester the probe from inadvertent use.

Operating Environment

Only use the product within this operating environment:

Temperature: 0° to 50° C

Humidity: Maximum relative humidity 90 % for temperatures up to 31° C decreasing linearly to

50% relative humidity at 40° C

Altitude: Up to 10,000 ft (3,048 m)

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Operator’s Manual

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Overview

Description

The AP034 is a wide band differential active probe. The probe features low noise, low input
capacitance, high common mode rejection, and FET-buffered inputs in the probe head. User
selectable attenuation and offset give the probe flexibility to measure a large range of signal
amplitudes. Plug-on attenuator and AC coupling accessories further extend the application range.
Interconnect accessories included 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. This provides a convenient low cost
method of creating device characterization test fixtures.

The probe is powered directly from a Teledyne 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 is ideal for acquiring high speed differential signals such as those found in disk drive
read channels, differential LAN, video, etc. It can also 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 the probe to be used as a 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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AP034 Active Differential Probe

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Standard Accessories

Hard Case

÷10 Plug-on Attenuator

÷20 Plug-on Attenuator

Plug-on AC Coupler

Probe Connection Accessory Kit:

Flex Lead Set (1)

Mini Clip, 0.8 mm (3)

Mini Clip, 0.5 mm (2)

Ground Lead (1)

Offset Pins, Round (4)

Square Pin Header Strip (1)

Manual, AP034 Active Differential Probe Operator’s Manual

Optional Accessories

ADPPS Power Supply

Oscilloscope Software Compatibility

For full control functionality of the probe, Teledyne LeCroy LC series oscilloscopes must have
software version 8.1.0 or higher loaded; all X-Stream oscilloscopes are compatible. The software
version installed in a Teledyne LeCroy oscilloscope can be verified by pressing the SHOW STATUS
button on the front panel (where available), then selecting the System menu choice. The probe can
be used with earlier versions of software; however, probe offset can only be controlled through the
buttons on the probe body. Also, the scale factor will be displayed incorrectly in some modes.

For information on upgrading the software in your oscilloscope, see
teledynelecroy.com/support/softwaredownload, or contact your local Teledyne LeCroy
representative.

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Specifications

Nominal Characteristics

Nominal characteristics describe parameters and attributes that have are guaranteed by design,
but do not have associated tolerances.

Input Configuration: True Differential (+ and – Inputs); with shield Ground connector.

Effective Gain1: X1, ÷10, ÷20

Input Coupling: DC. AC Coupling obtained by installing AC Coupling Adapter.

Differential Mode Range: ±400 mV (÷1 Attenuation)

±4 V (÷10 Attenuation)
±8 V (÷100 Attenuation)

Common Mode Range: ±16 V (÷1 Attenuation)

±42 V (÷10 Attenuation)
±42 V (÷20 Attenuation)

Maximum Input Voltage: ±42 V either input from Ground

Warranted Electrical Characteristics

Warranted characteristics are parameters with guaranteed performance. Unless otherwise noted,
tests are provided in the Performance Verification Procedure for all warranted specifications.

LF Gain Accuracy: 2% into 50 Ωload

2

, measured at 1 kHz

Common Mode Rejection Ratio3 (Probe head grounded, DC coupled attenuator):

70 Hz ≥ (80 dB)
1 MHz ≥ (40 dB)
250 MHz ≥ (25 dB)

1

÷10 and ÷20 obtained with external plug-on attenuators

2

Output impedance is 50 Ω, intended to drive 50 Ω. Add uncertainty of termination impedance to accuracy.

3

Teledyne LeCroy measures CMRR with a fixture that connects the probe tip ground to the signal source

ground. This method is necessary to obtain a reproducible CMRR measurement. Often, users leave the probe

tip ungrounded when measuring high frequency signals. Not grounding the probe tip can actually improve
CMRR by allowing some of the common mode signal to be impressed across the entire length of the probe
cable instead of from probe tip to probe ground. The CMRR improvement obtained without grounding the

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AP034 Active Differential Probe

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probe tip depends on proximity to probe cable ground, and is therefore non-reproducible. Teledyne LeCroy
has chosen to use a reproducible method of measurement, rather than obtain a more optimistic
measurement.

Typical Electrical Characteristics

Typical characteristics are parameters with no guaranteed performance. Tests for typical
characteristics are not provided in the Performance Verification Procedure.

Bandwidth, probe only (-3 dB): DC to 1 GHz

Output Zero: < 3 mV within 30 minutes of autobalance

Residual Autobalance Offset: ≤ 100 μV referred to input with X1 effective gain

Differential Offset Range: ≥1.6 V (÷1 Attenuation)

≥ 16 V (÷10 Attenuation)
≥ 42 V (÷20 Attenuation)

CMRR: See Figure 1.

Input Resistance (each side to Ground): 1 M_

Input Capacitance (between inputs): < 0.85 pF (See Figure 2.)

Input Capacitance (each side to Ground): < 1.5 pF (See Figure 2.)

Noise (referred to input, 10 to 1000 MHz): 35 nV/√Hz (÷1 Attenuation)

350 nV/√Hz (÷10 Attenuation)
700 nV/√Hz (÷20 Attenuation)

Output Impedance: 50 Ω nominal intended to drive 50 Ω

Harmonic Distortion (3rd order distortion): –60 dB below fundamental (200 mVp-p output at 100 MHz)
(3rd order intercept): +20 dBm (at 100 MHz at output)

AC Coupling LF Cutoff (-3 dB): 16 Hz (using plug-on AC Coupler)

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Operator’s Manual

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Figure 1, Typical CMRR Graphs

General Characteristics

Temperature: 0° to 50° C Operating

-40° to 75° C Storage

Input Connectors: Compatible with 0.025” (0.635 mm) square pins.

0.036” (0.91 mm) maximum diameter (for round pins)

Power Requirements: Powered from oscilloscope through ProBus interface
or with ADPPS power supply.

Dimensions

Control Housing: Length: 3.625 in (9.2 cm)
Width: 1.50 in (3.8 cm)
Height: 1.00 in (2.5 cm)

Head: Length: 4.0 in (10.1 cm) w/o Attenuator or AC Coupler
Width: 2.25 in (2.25 cm)
Height: 0.625 in (1.6 cm)

Cable: Length: 42 in (106 cm)
Diameter: 0.275 in (7.0 mm)

Weight: Probe only: 6.4 oz (0.18 kg)
Shipping: 2 lbs, 8.4 oz (1.15 kg)

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Operation

CAUTION: The input circuits in the AP034 incorporate components that protect the probe

from damage resulting from electrostatic discharge (ESD). Keep in mind that this is an active probe,
and it should be handled carefully to avoid damage. When using the AP034, you are advised to take
precautions against potential instrument damage due to ESD.

Connecting the Probe to the Test Instrument

When you are using the AP034 Active Differential Probe with a Teledyne LeCroy Oscilloscope
equipped with ProBus, attach the probe output connector to the oscilloscope input connector. The
oscilloscope will recognize the probe, set the oscilloscope input termination to 50Ω, and activate
the probe control functions in the user interface.

To use the AP034 Active Differential Probe with instrumentation not equipped with a ProBus
interface, it is necessary to use the ADPPS Power Supply. Attach the ADPPS connector to the probe
output connector. The output connector of the ADPPS is a standard male BNC that can be directly
connected to another instrument. If necessary, the output of the ADPPS can be interconnected
with a 50 Ω coaxial cable. To minimize the effect of skin loss, this cable should be 1 m or less in
length. The AP034 Active Differential Probe is designed to drive a 50 Ω load. The gain will be
uncalibrated if the output is not correctly terminated. If you are using the probe with an instrument
with a high input impedance, place a 50 instrument input before attaching the ADPPS.

Connecting the Probe to the Test Circuit

At the probe tip, two inputs and a ground connection are available for connecting the probe to a
circuit under test. For accurate measurements, both the + and – inputs must always be connected
to the test circuit. The ground connection is optional. Positive voltages applied to the + input
relative to the – input will deflect the oscilloscope trace toward the top of the screen.

To maintain the high performance capability of the probe in measurement applications, user care
in connecting the probe to the test circuit. Increasing the parasitic capacitance or inductance in the
input paths may introduce a “ring,” or slow the rise time of fast signals. To minimize these effects,
use the shortest length possible when connecting the probe to the circuit under test. Input leads
that form a large loop area (even shielded coaxial cables) will pick up any radiated magnetic field
that passes through the loop, and may induce noise in the probe inputs. Because this signal will
appear as a differential mode signal, the probe’s common mode rejection will not remove it. You
can greatly reduce this effect by using short interconnection leads, and twisting them together to
minimize the loop area.

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High common mode rejection requires precise matching of the relative gain or attenuation in the +
and – input signal paths. Mismatches in additional parasitic capacitance, inductance, delay, and a
source impedance difference between the + and – signal paths will lower the common mode
rejection ratio. Therefore, it is desirable to use the same length and type of wire and connectors for
both input connections. When possible, try to connect the inputs to points in the circuit with
approximately the same source impedance.

If AC coupling is desired, install the AC coupling accessory on the probe tip before connecting it to
the test circuit. The low-frequency cutoff (–3 dB point) of the AC coupler is approximately 16 Hz.

If the voltage in the test circuit exceeds the probe’s capability, add the external ÷10 or ÷20
attenuator* to the probe tip. If both the external attenuator and AC coupler are used, install the
attenuator on the probe tip first, then install the AC coupler on the attenuator input.

CAUTION: The external attenuators are precisely adjusted during manufacturing to match the

characteristics of the input of the probe with which they were shipped. The input characteristics of
the external attenuator itself do not exactly match those of the probe. Therefore, using the ÷10
and ÷20 attenuators at the same time is not recommended. The scale factor encoding system will
not operate correctly with both attenuators installed simultaneously.

The input characteristics of the AP034 1 GHz Active Differential Probe are significantly different
than those of the AP033 500 MHz Active Differential Probe. The external attenuators are not
interchangeable. The external attenuators currently supplied with the probes are labeled with the
appropriate model number. The attenuators supplied with model AP033 probes prior to the
introduction of the AP034 did not include the model number on the label. When using an external
attenuator with the AP034 Active Differential Probe, make sure it is labeled “AP034.”

Interchanging non-compatible attenuators will not damage the probes; however, the transient
response of the measured signals will be significantly in error.

In addition to being compatible with the included lead set, the probe input connectors will mate
with standard 0.025 in. (0.635 mm) square pins in any rotational orientation. To avoid damaging
the input connectors, do not attempt to insert connectors or wire larger than 0.036 in. (0.91 mm) in
diameter. Avoid rotating square pins after they are inserted into the input connectors.

The included accessories simplify the task of connecting the probe to the test circuit:

 Use the small (0.5 mm) mini clips with the flexible lead set when connecting to fine-pitch

surface mount IC leads.

 Use the larger (0.8 mm) mini clips to connect to through-hole leaded components.
 Use the offset round pins for hand-held probing applications. Reposition the pins by

rotating them to obtain the required spacing.

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Probe Input Loading

Attaching any probe to a test circuit will add some loading. In most applications, the high
impedance of the AP034 Active Differential Probe inputs imparts an insignificant load to the test
circuit. However at very high frequencies, the capacitive reactance of the probe’s input capacitance
may load the circuit enough to affect measurement accuracy. The equivalent model of the probe
input circuits is shown below:

Figure 2, AP034 Equivalent Input Model

Grounding the Probe

The single lead along with one of the larger (0.8 mm) mini clips can be used to ground the probe to
the test circuit. Insert the pin end of the lead into the receptacle marked:

CAUTION: Do not use the attenuator encoding receptacle (unmarked socket near the – input)

to ground the probe. Connection to the encoding receptacle will not provide adequate grounding
and may result in an incorrect effective gain indication.

In many cases it is not necessary to ground the probe to the circuit under test. However, if the test
circuit is isolated from earth ground, it is usually necessary to connect the probe ground to a point
in the circuit. Grounding test circuits that are referenced to earth ground may improve the fidelity
of high frequency components in the waveforms. The potential for improvement with grounding
will vary depending on the common mode source impedance. However, connecting the probe
ground to a circuit that is referenced to earth ground can create a ground loop that may add noise
to low amplitude signals. The rejection of high frequency common mode signals is improved when
the probe head is ungrounded.

The best recommendation for connecting or not connecting the probe ground is to try both
configurations and select the one that performs the best.

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NOTE The AP034 Active Differential Probe transmits the measured signal differentially through the
probe cable. This essentially eliminates signal degradation from ground loop effects within the
probe. However, creating a ground loop may introduce signal distortions in the test circuit itself, or
in any coaxial cable between the ADPPS power supply and the test instrument.

Selecting the Proper Range

The AP034 Active Differential Probe has a fixed gain of X1 (unity). Use of the ÷10 or ÷20 external
attenuators reduces the amplitude of the input signal when it is necessary to extend the dynamic
operating range of the probe. Attenuating the input signal increases both the differential mode
range and common mode range of the probe. Refer to the block diagram below.

Figure 3 AP034 Block Diagram

By using the plug-on attenuator, you can extend the attenuation range to ÷20. Do not use the ÷10
and ÷20 plug-on attenuators simultaneously. The maximum ranges are given in the following table:

Table 1. AP034 Dynamic ranges and input capacitance at different attenuator settings

÷1 Attenuation

(Probe Only)

÷10

Attenuation

÷100

Attenuation

Common Mode Range

•±16 V

±42 V •

±42 V

Differential Mode Range*

•±400 mV •

±4 V •

±8 V

*Offset moves the center point of this range.

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When using a differential probe or amplifier, be careful to avoid exceeding the common mode
range. Because the common mode signal is rejected by the differential probe, and is not displayed,
changes in the amplitude of the common mode component are not apparent to the user.
Exceeding the common mode range may introduce distortion into the AP034 output.

Circuitry in the probe detects the presence of either attenuator, and displays the effective gain of
the probe on the probe front panel.

Operation with Teledyne LeCroy Oscilloscopes

When the AP034 probe is connected to a Teledyne LeCroy oscilloscope equipped with ProBus
interface, the displayed scale factor will be adjusted to account for the effective gain of the probe.
The channel OFFSET knob will control the probe offset, rather than the offset at the oscilloscope
input. The probe control menu can be activated by pressing the COUPLING button (if available)
while the channel to which the probe is attached is selected.

When the AP034 Active Differential Probe is first connected to the oscilloscope, the following
message will appear: “WARNING: Probe offset buttons are locked.” This alerts you that offset
control must be made through the oscilloscope, rather than through the buttons located on the
probe. It does not indicate a failure in the probe or oscilloscope.

NOTE: Correct display of scale factor with the ÷20 attenuator installed and correct operation of
probe offset require that software version 8.1 or higher be loaded. Refer to “Oscilloscope Software
Compatibility” for additional information.

Using AP034 with the APPPS Power Supply

The optional ADPPS Power Supply allows the AP034 Active Differential Probe to be used with
instruments that are not equipped with the ProBus interface. When used with the ADPPS, the
AP034 must be terminated into 50Ω . If the test instrument input impedance is not 50Ω insert a
50Ω in-line terminator between the ADPPS and the instrument input. If a coaxial extension cable is
used, the terminator should be located at the instrument end of the cable. Note that the additional
parasitic losses of extension cables may reduce the usable bandwidth of the system below the
AP034 specification.

To prevent signal distortion, it is necessary to keep the AP034 output less than 400 mV at all times.

With the ProBus interface (see note on following page), the oscilloscope OFFSET control actually
controls the AP034 offset. Without the ProBus, it is acceptable to use the oscilloscope to position
the waveform at high sensitivities, but it is a practice that can lead to erroneous measurements
when the probe output exceeds ±400 mV. Therefore, when the ADPPS is used, it is preferable to
use the AP034 offset function to perform all waveform positioning.