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LeCroy AP034 Instruction Manual

Active differential probe
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/H&UR\ $3
$FWLYH 'LIIHUHQWLDO 3UREH
REVISION D — JANUARY 2000

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  • Page 1 ,QVWUXFWLRQ 0DQXDO /H&UR\ $3 $FWLYH 'LIIHUHQWLDO 3UREH REVISION D — JANUARY 2000...
  • Page 2 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.

  • Page 3: Table Of Contents

    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 ..................
  • Page 4 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 ISSUED: January 2000 AP034-OM-E Rev D...
  • Page 5 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 # # # AP034-OM-E Rev D ISSUED: January 2000...
  • Page 6 $3 $FWLYH 3UREH BLANK PAGE ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 7: Description

    (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.

  • Page 8: Conventions Used In This Manual

    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 # # # ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 9: Operator Safety

    6DIHW\ ,QIRUPDWLRQ 6DIHW\ ,QIRUPDWLRQ 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.
  • Page 10 $3 $FWLYH 3UREH BLANK PAGE ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 11: Connecting The Probe To The Test Instrument

    50 Ÿ FRD[LDO FDEOH 7R PLQLPL]H WKH HIIHFWV of skin loss, this cable should be 1 m or less in length. The AP034 Active Differential Probe is designed to drive a 50 Ÿ ORDG The gain will be uncalibrated if the output is not correctly terminated.
  • Page 12 AC coupler are used, install the attenuator on the probe tip first, then install the AC coupler on the attenuator input. * Note The external attenuators are precisely adjusted during manufacturing match ² ISSUED: January 2000 AP034-OM-E Rev D...
  • Page 13 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.”...

  • Page 14: Probe Input Loading

    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...
  • Page 15 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.

  • Page 16: Selecting The Proper Range

    $3 $FWLYH 3UREH 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.

  • Page 17: Operation With Lecroy Oscilloscopes

    OPERATION WITH LECROY OSCILLOSCOPES When the AP034 probe is connected to a LeCroy oscilloscope equipped with ProBus interface, the displayed scale factor will be adjusted to account for the effective gain of the probe. The...

  • Page 18: Ap034 Use With The Adpps Power Supply

    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 50 Ÿ ,I WKH WHVW LQVWUXPHQW input impedance is not 50 Ÿ LQVHUW D  Ÿ LQOLQH WHUPLQDWRU between the ADPPS and the instrument input.
  • Page 19 Input Differential Mode Range plus the offset used. See Adding Offset on the following page. When using the AP034 with the ADPPS power supply on oscilloscopes without ProBus interface, use the following table to select the desired effective volts per division and determine the offset available.

  • Page 20: Adding Offset

    Waveform with no offset Figure 4. Effect of Differential Offset When the AP034 Active Differential Probe is used with a LeCroy oscilloscope equipped with ProBus interface, the probe offset can be controlled with the channel O knob.* The buttons on FFSET the probe housing will be disabled.

  • Page 21: Autobalance

    O buttons for two FFSET seconds. The AP034 must be terminated into 50 Ÿ IRU VXFFHVVIXO Autobalance. Upon successful completion of the Autobalance cycle, all three of the EFFECTIVE GAIN indicators will be briefly illuminated. If an input signal is present during auto balance and the routine fails, the EFFECTIVE GAIN indicators will not illuminate.

  • Page 22: Designing Test Fixtures For The Ap033 Probe

    To facilitate use with custom test fixtures, the input receptacles used in the AP034 probe are compatible with commercially available 0.025 in. (0.635 mm) square pins. The receptacles do not require a specific rotational orientation for the square pin.

  • Page 23: Differential Mode And Common Mode

    Because the Common Mode signal is normally rejected, and is not displayed on the oscilloscope, you need to be careful to avoid accidentally exceeding the common mode range. ² AP034-OM-E Rev D ISSUED: January 2000...

  • Page 24: Common Mode Rejection Ratio

    Hence, CMRR is usually specified as a plot versus common mode frequency. The common mode frequency in these plots is assumed to be sinusoidal. In real life applications, the common mode signal is ² ISSUED: January 2000 AP034-OM-E Rev D...
  • Page 25 As such, it is very difficult to predict actual performance in the application for CMRR-versus-frequency graphs. The practical application of these graphs is to compare the relative common mode rejection performance between different probes or amplifiers. # # # ² AP034-OM-E Rev D ISSUED: January 2000...
  • Page 26 $3 $FWLYH 3UREH BLANK PAGE ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 27: Cleaning

    SERVICE STRATEGY The AP034 circuits utilize fine pitch surface mount devices; it is, therefore, impractical to attempt repair in the field. Defective probes must be returned to a LeCroy service facility for diagnosis and exchange.

  • Page 28: Incorrect Frequency Response

    If so, remove all other ProBus accessories from the oscilloscope. Is the message still displayed? If so, remove the AP034. Is the message still displayed? If so, the oscilloscope should be returned for service. 8. If, after removing the AP034, the Power Supply Overload error message is not displayed, the problem may be either the probe or the oscilloscope.

  • Page 29: Dc Errors

    Use the procedure listed in this section to match the attenuator. 2. If the common mode signal appears when the probe is connected to the test circuit, but not when it is attached to ² AP034-OM-E Rev D ISSUED: January 2000...

  • Page 30: Returning A Defective Probe

    The procedure for returning a defective probe to be exchanged, is as follows: Contact your local LeCroy sales representative to find out where to return the product. All returned products should be identified by model and serial number. You should describe the defect or failure, and provide your name and contact number.

  • Page 31: Replacement Parts

    &DUH DQG 0DLQWHQDQFH 6. Mark the outside of the box with the shipping address given to you by the LeCroy representative; be sure to add the following: • ATTN: <RAN assigned by the LeCroy representative> • FRAGILE 7. Insure the item for the replacement cost of the probe.
  • Page 32 $3 $FWLYH 3UREH Figure 7. Replceable Parts ² ISSUED: January 2000 AP034-OM-E Rev D...
  • Page 33 &DUH DQG 0DLQWHQDQFH Reference LeCroy Part Number Description Qty. 529-304-001 Plastic probe tip housing Top 377-000-007 LeCroy AP034 Probe Tip Label 529-304-003 Plastic probe tip housing End 529-304-002 Plastic probe tip housing Bottom 555-001-000 #2 Allen Screw, Black 554-425-003 Screw, M 2.5x6, self tapping...

  • Page 34: Matching Procedure For ÷10 Plug-On External Attenuator

    MATCHING PROCEDURE FOR ÷10 PLUG-ON EXTERNAL ATTENUATOR The ÷10 and ÷20 Plug-on attenuators provided as standard accessories with the AP034 are calibrated to match the specific probe they are shipped with. Individual probes will have small variations in parasitic capacitance within the input circuits. To...

  • Page 35: Procedure

    ProBus, use the ADPPS to provide power for the AP034. 2. Attach the ÷10 or ÷20 Attenuator Adapter to the AP034 probe tip. 3. Insert 0.025 in. (0.635 mm) square pins into the +, –, and input connectors of the Plug-on Attenuator.
  • Page 36 Attenuator, and not the AC Coupler.) 8. Set the test oscilloscope Volts/Div to 200 mV (for LeCroy oscilloscopes with ProBus) or 20 mV/Div when using the ADPPS with an oscilloscope without scale factor correction;...
  • Page 37 13. Set the signal generator frequency to about 50 Hz, and the output amplitude to about 10 V. 14. Set the test oscilloscope Volts/Div to 20 mV (for LeCroy oscilloscopes with ProBus) or 2 mV/Div when using the ADPPS with an oscilloscope without scale factor correction;...
  • Page 38 +LF Comp adjustment, the added capacitance of the adjustment tool may change the amplitude of the waveform when it is inserted. The correct adjustment is achieved when the overshoot is minimized with the adjustment tool removed. # # # ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 39: Test Equipment Required

    AP034 Active Differential Probe. The recommended calibration interval for the model AP034 Active Differential Probe is one year. The complete performance verification procedure should be performed as the first step of annual calibration. You can record test results on a photocopy of the Test Record provided at the end of this section.
  • Page 40 BNC female-to-banana plug Pomona 1269 Notes If a LeCroy ProBus equipped oscilloscope is not available, you may use an alternate oscilloscope that meets the other minimum specifications listed, and the model ADPPS power supply, to perform the adjustment procedure. The input ²...

  • Page 41: Preliminary Procedure

     DQG WKH offset or position must remain at center screen. PRELIMINARY PROCEDURE Connect the AP034 Active Differential Probe to the female end of the ProBus Extension Cable. Connect the male end of the ProBus extension cable to Channel 1 of the oscilloscope.

  • Page 42: Check Gain Accuracy

    Differential Drive No Termination portion of the AP03x- CF01 Calibration Fixture with the input receptacles in the AP034 probe head. Press the probe into the fixture to fully engage the pins. 11. Connect the banana plugs of the precision terminator to the digital multimeter (DMM).
  • Page 43 Mode Gain assumed to be unity (1.0). 1. Disconnect the ProBus Extension cable from the AP034 and the oscilloscope. Reconnect the AP034 directly to the Channel 1 input of the oscilloscope. 2. Carefully move the AP034 probe head from the Differential...
  • Page 44 Termination connector. Make sure that the probe is fully engaged in the fixture. 3. Set the oscilloscope to display channel 1. In the oscilloscope Channel 1 “COUPLING” menu, set Coupling to DC 1 MΩ, and Global BWL to Off. Autobalance the AP034 by pressing AUTOBALANCE menu button twice.
  • Page 45 Fixture is being used and not the Differential Drive 50 ohm Termination connector. 13. Measure the peak-to-peak output amplitude of the AP034. Record the reading to two-digit resolution (xx mV) as “Common Mode Signal at 100 MHz” in the Test Record.

  • Page 46: Check Low Frequency Cmrr

    Function Generator will be used in place of the high-frequency sine wave generator for the low frequency CMRR test. 1. Carefully move the AP034 probe head from the Common Mode Drive 50 ohm Termination connector of the AP033/AP034 Calibration Fixture to the Common Mode Drive No Termination connector.
  • Page 47 1 and the A Math waveform (averaged channel 1). Adjust the scale factor of channel 1 and the Zoom of the A Math waveform as necessary to accurately measure the amplitude of the averaged signal. ² AP034-OM-E Rev D ISSUED: January 2000...
  • Page 48 16. Verify that the Common Mode Rejection Ratio at 1 MHz is greater than 100:1 (40 dB). 17. Remove all cables and test fixtures from the AP034 probe. This completes the Performance Verification of the AP034. Complete and file the results recorded in the AP034 Performance Verification Test Record, as required by your quality procedures.

  • Page 49: Performance Verification Test Record

    AP034 Performance Verification Test Record This record can be used to record the results of measurements made during the performance verification of the AP034 Active Differential Probe. Photocopy this page and record the results on the copy. File the completed record as required by applicable internal quality procedures.
  • Page 50 $3 $FWLYH 3UREH AP034 PERFORMANCE VERIFICATION TEST RECORD Step Description Intermediate Data Test Result Gain Accuracy Sine Wave Generator Output Voltage ________________ mV A-13 Probe Output Voltage ________________ mV Gain Error (Test Limit ” “2%) A-15 _________________ % High Frequency Common Mode Rejection Ratio (CMRR)

  • Page 51: Introduction

    $GMXVWPHQW 3URFHGXUH $GMXVWPHQW 3URFHGXUH INTRODUCTION You can use this procedure to adjust the AP034 Active Differential Probe to meet the warranted specifications. This procedure should only be performed if the instrument fails the Performance Verification tests. If the probe cannot be adjusted to meet the Performance Verification limits, repair may be necessary.

  • Page 52: Test Equipment Required

    If alternate test equipment is substituted, control settings or calibration equipment setups may need to be altered. Alternate models of test equipment may have different connector styles requiring adapters not included in the equipment list. ² ISSUED: January 2000 AP034-OM-E Rev D...
  • Page 53 50 Hz to 1 MHz frequency range DS340 Sync. or Freq. Reference output Leader LAG-120B Fast Rise Pulse Risetime < 2 ns Calibrator signal from LeCroy $PSOLWXGH !  P9 LQWR  Generator oscilloscope Over/Undershoot < 6% Tegam / Tektronix PG506 with...

  • Page 54: Preliminary Procedure

    Screwdriver * Notes If a LeCroy ProBus equipped oscilloscope is not available, you may perform the adjustment procedure with an alternate oscilloscope that meets the other Minimum Specifications, and the PRGHO $'336 SRZHU VXSSO\ 7KH LQSXW WHUPLQDWLRQ RI WKH RVFLOORVFRSH PXVW EH VHW WR ...
  • Page 55 Connect the AP034 Active Differential Probe output to the female end of the ProBus Extension Cable. Be careful to align the ProBus pins with the corresponding connector correctly.
  • Page 56 Remove or redirect any fans that may be blowing air currents over the probe tip during adjustment. Note Correct operation of the AP034 Active Differential Probe controls requires software version 8.1.0 or higher. You can find out the software version loaded on your LeCroy scope by pressing SHOW STATUS, then selecting the System menu option.

  • Page 57: Procedure

    4. Plug the precision 50 Ÿ WHUPLQDWRU LQWR WKH '00 LQSXW 6HW the DMM to measure DC volts. 5. Using a low capacitance screwdriver, adjust Coarse DC Bal (R226) on the Amplifier Board for an output voltage of 0 mV ±10 mV (Figure 10). ² AP034-OM-E Rev D ISSUED: January 2000...

  • Page 58: Adjust Fine Dc Balance (R304)

    SHORT connector on the AP033/AP034 Calibration Fixture. The SHORT connector is the only BNC connector on the AP033/AP034 Calibration Fixture that does not have corresponding input pins for the probe tip. It is located on the end of the board beyond the Common Mode Terminated connector.

  • Page 59: Adjust Low Frequency Cmrr (R7)

    3. Connect a second BNC cable from the Function Generator SYNC OUT to the external trigger input of the oscilloscope. 4. Set the Function Generator waveform to Sine and the frequency to 70 Hz. ² AP034-OM-E Rev D ISSUED: January 2000...
  • Page 60 Common Mode Drive No Termination portion of the AP033/AP034 Calibration Fixture with the input receptacles in the AP034 probe head. Press the probe into the fixture to fully engage the pins. 10. Set the oscilloscope to display channel 3. The waveform is the common mode signal.

  • Page 61: Adjust Offset (R330)

    2. Set the oscilloscope channel 1 scale factor to 10 mV/div, and the acquisition mode to Auto. Set the BWL to 20 or 25 MHz. Adjust the OFFSET to 0.0 mV 3. Carefully move the AP034 probe tip from the Common Mode Drive No Termination position of the AP033/AP034 Calibration...
  • Page 62 10. Set the probe offset to –1.600 V by rotating the OFFSET knob in the channel section of the oscilloscope. 11. Allow 10 seconds for the AP034 to stabilize. 12. Using a low capacitance screwdriver, adjust Offset (R330) to bring the trace back to exactly center screen. (See Figure 10 for adjustment location.)

  • Page 63: Adjust Gain (R322C)

    AP034 for the next step. E. Adjust GAIN (R322C) 1. Set the AP034 offset to 0.000 V by rotating the OFFSET knob in the CHANNEL section of the oscilloscope. 2. Disconnect the BNC cable from the oscilloscope end of the ProBus extension cable.

  • Page 64: Adjust Final Attenuator Compensation (C17)

    7. Remove the banana plug adapter and connect the free end of the cable to the Differential Drive no Termination connector on the calibration fixture. 8. Connect the AP034 Output cable with 50 Ω Precision termination to the DMM. 9. Using a low capacitance screwdriver, adjust GAIN (R322C) so that the DMM reading is within ±1 mV (0.5%) of the...

  • Page 65: Adjust Final Attenuator Cmrr (C18A)

    G. Adjust Final Attenuator CMRR (C18A) 1. Carefully move the AP033 probe head from the Differential Drive 50 ohm Termination portion of the AP033/AP034 Calibration Fixture to the Common Mode Drive 50 ohm Termination portion. 2. Remove the BNC cable from the Differential Drive 50...

  • Page 66: Assemble Probe And Amplifier

    7. Insert and tighten the two screws that secure the end panel to the ProBus interface housing. Avoid overtightening the screws because the cover may warp. 8. Replace the four push button caps, pressing each fully to seat the cap on the button shaft. ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 67: Attenuator Matching And Final Check

    2. Perform the Attenuator Matching Procedure listed on page 5-8. Apply calibration seals in accordance with your quality procedures. This concludes Adjustment Procedure. Repeat Performance Verification procedure to complete the calibration of the AP034. # # # ² AP034-OM-E Rev D ISSUED: January 2000...
  • Page 68 $3 $FWLYH 3UREH BLANK PAGE ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 69: Nominal Characteristics

    6SHFLILFDWLRQV 6SHFLILFDWLRQV The following specifications are valid for model AP034 probes after the probe has reached operating temperature. This takes 20 minutes with power applied, in an environment with stable ambient temperature. The probe must be operating within the environmental conditions listed in the General Characteristics section, and must have been calibrated within the past 12 °...

  • Page 70: Warranted Electrical Characteristics

    The CMRR improvement obtained without grounding the probe tip depends on proximity to probe cable ground; therefore, it is nonreproducible. LeCroy has chosen to use a reproducible method of measurement, rather than obtain a more optimistic measurement. ²...

  • Page 71: Typical Electrical Characteristics

    –60 dB below fundamental (200 mV output, at 100 MHz) order intercept: +20 dBm (at 100 MHz at output) AC Coupling LF Cutoff (–3 dB): 16 Hz (using plug-on AC coupler) ² AP034-OM-E Rev D ISSUED: January 2000...
  • Page 72 $3 $FWLYH 3UREH Figure 13. Typical CMRR Graphs ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 73: General Characteristics

    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) ² AP034-OM-E Rev D ISSUED: January 2000...

  • Page 74: Compliance And Certifications

    The use of the probe and/or the instrument it is connected to in a manner other than 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. ² ISSUED: January 2000 AP034-OM-E Rev D...

  • Page 75: Standard Accessories

    OPTIONAL ACCESSORIES ADPPS Power Supply OSCILLOSCOPE SOFTWARE COMPATIBILITY For full control functionality of the probe, the LeCroy oscilloscope must have software version 8.1.0 or higher loaded. The software version installed in a LeCroy oscilloscope can be verified by pressing the S...
  • Page 76 $3 $FWLYH 3UREH BLANK PAGE ² ISSUED: January 2000 AP034-OM-E Rev D...

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