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Keysight Technologies N2750A User Manual

Differential probes
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Keysight N2750/1/2A
Differential Probes
User's Guide

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Summary of Contents for Keysight Technologies N2750A

  • Page 1 Keysight N2750/1/2A Differential Probes User’s Guide...

  • Page 2: Safety Notices

    52.227-14 (June Pursuant to FAR 12.212 and 27.405-3 1987) or DFAR 252.227-7015 (b)(2) © Keysight Technologies, Inc. 2014, 2019 and Department of Defense FAR Sup- (November 1995), as applicable in any No part of this manual may be reproduced in plement ("DFARS") 227.7202, the U.S.

  • Page 3: Table Of Contents

    Functional Test / 22 Inspecting the Probe / 23 Cleaning the Probe / 23 Returning the Probe for Service / 24 Contacting Keysight Technologies / 24 Safety Information / 25 Instrument Markings and Safety Symbols / 27 N2750/1/2A User’s Guide...
  • Page 4 Contents SPICE Models N2752A probe with the N2776A Browser Tip / 30 N2750A probe with the N2777A Solder-In Tip / 33 Measured Versus Modeled Input Impedance / 36 Probe Calibration Calibrating the Probe / 40 Characteristics and Specifications Dimensions / 46...

  • Page 5: Using The Probes

    N2750A: ........1.5...

  • Page 6: Probe Features

    Using the Probes Probe Features The N2750/1/2A differential probes feature a probe Quick Action button, light, channel identification rings, and three different exchangeable snap-on probe tips: browser, solder-in, and socketed. To learn more about the probe tips, refer to “Exchangeable Probe Tips” on page 10.

  • Page 7: Oscilloscope Compatibility

    3.5 GHz 3 GHz 2.5 GHz Single-Ended 3.5 GHz 1.2 GHz 2 GHz Common-Mode 1 GHz 1.4 GHz N2750A 1.5 GHz at 2:1 / 10:1 Differential 1.5 GHz 1.5 GHz 1.5 GHz Single-Ended 1.5 GHz 1.2 GHz 1.5 GHz Common-Mode 1 GHz 1.4 GHz...

  • Page 8: Available Accessories

    Using the Probes Available Accessories The following table shows the accessories that are available for use with the probes. Table 2 Available Accessories Model Number Accessory N5442A Precision BNC adapter for use with 90000 Q/X-Series oscilloscopes N2787A 3D probe positioner E2655B/C or Performance verification and deskew fixture.

  • Page 9: Quick-Action Button And Probe Light

    Using the Probes Quick-Action Button and Probe Light Press the quick-action button to turn the probe light on and off. Pressing and holding the button will increase and decrease the light’s intensity. Using the oscilloscope’s Probe Configuration dialog box, you can re-assign the button’s function.

  • Page 10: Exchangeable Probe Tips

    Using the Probes Exchangeable Probe Tips The probe comes with three unique tips for different probing situations. They are the browser, solder-in, and socketed tips as shown in Table 3 and described later in this section. For information on using the solder-in and socketed tips with InfiniiMode, refer to “InfiniiMode”...

  • Page 11: To Attach A Tip

    Using the Probes To Remove a Tip Hold the probe in one hand while holding the body of the tip in the other hand. Gently pull the probe tip straight off the probe. Do not remove the tip by pulling on the tip leads. CAUTION Figure 3 Do not pull on the tip leads...

  • Page 12: N2776A Browser Tip

    N2751A Probe Amplifier: ......3.5 GHz N2750A Probe Amplifier: ......1.5 GHz As the N2776A browser tip can only be used in differential mode, it is not compatible with InfiniiMode.
  • Page 13 N2751A Probe Amplifier: ......2.5 GHz N2750A Probe Amplifier: ......1.5 GHz When installing the tip on the probe, the tip’s symmetrical design allows you to...
  • Page 14 N2751A Probe Amplifier: ......3 GHz N2750A Probe Amplifier: ......1.5 GHz When installing the tip on the probe, the tip’s symmetrical design allows you to...

  • Page 15: Placing The Signal Within The Probe's Dynamic Range

    Using the Probes Placing the Signal Within the Probe’s Dynamic Range When making single-ended or common mode measurements, you can apply vertical offset to place the signal within the probe’s dynamic range. Vertical offset centers a signal at 0V on the oscilloscope’s display by compensating for the signal’s DC component.

  • Page 16: Infiniimode

    Using the Probes InfiniiMode The probes, when fitted with a socketed or solder-in tip, are InfiniiMode compatible. InfiniiMode allows you to switch between differential, single-ended, and common mode measurements without needing to change or reconnect the probe or probe leads. The following table shows, depending on the probe tip and InfiniiMode setting, which signal types can be measured.
  • Page 17 Using the Probes Making InfiniiMode Connections When probing a differential or common mode signal, connect the probe tips as shown in the example circuit of Figure 9. Notice that the sides of the probe are marked A and B to identify the two signal leads. Figure 9 Example InfiniiMode Probe Circuit Connections NOTE...
  • Page 18 Using the Probes The following measurements can be made without reconnecting the probe tips. In the equations, the A and B variables represent the signal from the A and B probe leads. Figure 10 Lead Identification on Probe Body Differential –...

  • Page 19: Probe Configuration Dialog Box

    Using the Probes Probe Configuration Dialog Box When the probe is connected to an Infiniium oscilloscope (9000 Series, 90000 Series, or 90000 Q/X-Series), the Probe Configuration dialog box automatically opens as shown in Figure 11. The oscilloscope automatically detects the signal type, which is indicated in the dialog box.

  • Page 20: Quick-Action Button

    3.50 or above. To reassign the probe button, click Utilities > Probe Configuration. In the Probe Configuration dialog box, click the tab for the N2750A, N2751A, or N2752A probe and then select the desired action in the Quick Action field.
  • Page 21 Using the Probes Quick Action Selections You can select one of the following probe button Quick Actions. Toggle Headlight Turns the probe light on and off. This is the default button configuration. Adjust Headlight Intensity Hold the button down, and the light’s intensity increases and decreases. Run/Stop Toggles between continuous data acquisition and stopping data acquisition.

  • Page 22: Probe Attenuation Ratio

    Using the Probes Refer to the oscilloscope’s online help for information on Multipurpose functions. No Action Disables the probe button. Probe Attenuation Ratio The probe’s attenuation ratio can be set to 2:1 or 10:1. When you attach the probe to the Infiniium oscilloscope, the AutoProbe interface automatically sets the probe attenuation to the value necessary to make the dynamic range of the probe greater or equal to the level required to measure the current input signal.

  • Page 23: Inspecting The Probe

    • Check the accessories. • If the contents are incomplete or damaged, notify your Keysight Technologies Sales Office. • Inspect the probe. If there is mechanical damage or defect, or if the probe does not operate properly or pass calibration tests, notify your Keysight Technologies Sales Office.

  • Page 24: Returning The Probe For Service

    If the probe is found to be defective we recommend sending it to an authorized service center for all repair and calibration needs. Perform the following steps before shipping the probe back to Keysight Technologies for service. 1 Contact your nearest Keysight sales office for information on obtaining an RMA number and return address.

  • Page 25: Safety Information

    Using the Probes Safety Information To avoid personal injury and to prevent fire or damage to this product or products connected to it, review and comply with the following safety precautions. Be aware that if you use this probe assembly in a manner not specified, the protection this product provides may be impaired.
  • Page 26 Using the Probes The probe cable is a sensitive part of the probe and, therefore, you should CAUTION be careful not to damage it through excessive bending or pulling. Avoid any mechanical shocks to this product in order to guarantee accurate performance and protection.

  • Page 27: Instrument Markings And Safety Symbols

    Using the Probes Instrument Markings and Safety Symbols Symbol Description STANDBY and AC symbols. The STANDBY marks the position of the instrument power line switch. The AC symbol is used to indicate the required nature of the line module input power. The CE mark is a registered trademark of the European Community.
  • Page 28 Using the Probes N2750/1/2A User’s Guide...

  • Page 29: Spice Models

    N2750A probe with the N2777A Solder-In Tip This chapter presents input impedance SPICE models for the combinations of N2752A probe with N2776A Browser tip and N2750A probe with N2777A solder-in tip. SPICE sub-circuit file listings are provided so that you can copy and paste the...

  • Page 30: N2752A Probe With The N2776A Browser Tip

    SPICE Models N2752A probe with the N2776A Browser Tip The following SPICE RLC circuit models the input impedance of the N2752A and N2776A combination. See Figure 14 on page 32 to view the matching between the measured and modeled input impedance. Figure 13 SPICE Model N2750/1/2A User’s Guide...
  • Page 31 SPICE Models SPICE Data Copy and paste the following lines of data into your SPICE simulations. .subckt N2750_Browser 1 2 C7 15 5 153f L9 5 4 1n R16 4 3 231 C1 15 8 60f C2 15 10 835f L1 8 7 1.2n L2 10 9 6.3n R1 7 3 7.7...
  • Page 32 SPICE Models Measured Versus Modeled Input Impedance The following plot shows how well the modeled impedance tracks the measured impedance. Figure 14 Input Impedance, Measured and Modeled (Differential) N2750/1/2A User’s Guide...

  • Page 33: N2750A Probe With The N2777A Solder-In Tip

    SPICE Models N2750A probe with the N2777A Solder-In Tip The following SPICE RLC circuit models the input impedance of the N2750A and N2777A combination. Observe the following items when positioning the tip wires: • It is assumed that the tip wires are approximately parallel and connected to the target at approximately 100 mils spacing.
  • Page 34 SPICE Models Figure 16 SPICE Model N2750/1/2A User’s Guide...
  • Page 35 SPICE Models SPICE Data Copy and paste the following lines of data into your SPICE simulation deck. .subckt N2777A_N2750A_InputZ 1 2 3 C25 1 2 53.7f R1 1 4 129.3 R2 2 5 129.3 C1 4 3 82.1f c4 3 5 82.1f c6 4 5 1.965f l1 4 6 5.14n l3 5 7 5.14n...

  • Page 36: Measured Versus Modeled Input Impedance

    SPICE Models k9 l4 l6 .3794 k8 l4 l5 .0954 k7 l6 l5 .3794 k12 l7 l9 .3794 k11 l7 l8 .0954 k10 l9 l8 .3794 .ends Measured Versus Modeled Input Impedance The following plots show how well the modeled impedance tracks the measured impedance.
  • Page 37 SPICE Models Figure 18 Differential Input Impedance (Measured, Modeled) Figure 19 Common Mode Input Impedance (Measured, Modeled) N2750/1/2A User’s Guide...
  • Page 38 SPICE Models N2750/1/2A User’s Guide...

  • Page 39: Probe Calibration

    Keysight N2750/1/2A Differential Probes User’s Guide 3 Probe Calibration Always calibrate the probe before making any critical measurements. A probe calibration removes attenuation errors, offset errors, and timing delays that are introduced by the probe. Additional information on the probe calibration procedure is located in the oscilloscope’s online help.

  • Page 40: Calibrating The Probe

    Probe Calibration An optional N2787A 3D Probe Positioner or equivalent can be used to hold the probe during the calibration. Always wear an ESD wrist strap when working with active probes. Not CAUTION doing so can result in the probe becoming permanently damaged. Calibrating the Probe 1 Turn on the oscilloscope.
  • Page 41 Probe Calibration • Clamp the probe leads to the PV fixture’s signal or ground. Position the probe tips on the PV fixture as shown in Figure 21. When using the solder-in tip, use the fixture’s spring-loaded clamps to hold the leads. Figure 21 Example of Proper Lead Placement on an E2655B PV Fixture (Browser Tip Shown)
  • Page 42 Probe Calibration N2750/1/2A User’s Guide...

  • Page 43: Characteristics And Specifications

    Keysight N2750/1/2A Differential Probes User’s Guide 4 Characteristics and Specifications This chapter provides the characteristics and specifications for the N2750/1/2A differential active probes. The probe and oscilloscope should be warmed up for at least 20 minutes before any testing and the environmental conditions should not exceed the probe’s specified limits.
  • Page 44 Characteristics and Specifications Table 5 Electrical Characteristics and Specifications (Sheet 1 of 2) Model Number N2750A N2751A N2752A Probe Bandwidth (–3 dB) 1.5 GHz 3.5 GHz 6 GHz (warranted), 7 GHz (typical) Rise time, probe only (10 – 90%) 233 ps 100 ps 58.3 ps...
  • Page 45 Characteristics and Specifications Table 5 Electrical Characteristics and Specifications (Sheet 2 of 2) Model Number N2750A N2751A N2752A Maximum Signal Slew Rate 30V/ns (differential, 10:1) 15V/ns (single-ended, 10:1) Zero Offset Error Referred to Input < 30 mV before calibration scope <...

  • Page 46: Dimensions

    Characteristics and Specifications Dimensions Figure 22 Probe and Tip Dimensions Figure 23 Tip Spacing on N2776A Browser Tip N2750/1/2A User’s Guide...

  • Page 47: Performance Data Plots

    Keysight N2750/1/2A Differential Probes User’s Guide 5 Performance Data Plots With N2776A Browser Tip (2:1 Attenuation) With N2776A Browser Tip (10:1 Attenuation) With N2777A Solder-In Tip (2:1 Attenuation) With N2777A Solder-In Tip (10:1 Attenuation) With N2778A Socketed Tip (2:1 Attenuation) With N2778A Socketed Tip (10:1 Attenuation) This chapter provides the performance plots for the N2752A probe with the browser, solder-in, and socketed tips.

  • Page 48: With N2776A Browser Tip (2:1 Attenuation)

    Performance Data Plots With N2776A Browser Tip (2:1 Attenuation) Figure 24 Frequency Response (Differential) Figure 25 CMRR, Differential (2:1 10:1 Attenuation) N2750/1/2A User’s Guide...
  • Page 49 Performance Data Plots Figure 26 Time Response to an Ideal Steip at Probe Tip (Differential) (Step Response) Figure 27 Time Response to a 136 ps Step at Probe Tip (Differential) (Step Tracking) N2750/1/2A User’s Guide...
  • Page 50 Performance Data Plots Red. V : Differential 100 ohm source (source and load terminated) with no load applied. source Blue. V : Same source with N2752A loading applied. Figure 28 Loading Effect of N2752A (Differential) Figure 29 Input Impedance (Differential) N2750/1/2A User’s Guide...
  • Page 51 Performance Data Plots The SPICE model for the green “Modeled” plot shown in Figure 30 below is described in “N2752A probe with the N2776A Browser Tip” on page 30. Figure 30 Input Impedance, Measured and Modeled (Differential) N2750/1/2A User’s Guide...

  • Page 52: With N2776A Browser Tip (10:1 Attenuation)

    Performance Data Plots With N2776A Browser Tip (10:1 Attenuation) Figure 31 Frequency Response (Differential) Figure 32 CMRR, Differential (10:1 Attenuation) N2750/1/2A User’s Guide...

  • Page 53: With N2777A Solder-In Tip (2:1 Attenuation)

    Performance Data Plots With N2777A Solder-In Tip (2:1 Attenuation) Figure 33 Frequency Response (ASE) Figure 34 CMRR, Differential (2:1 10:1 Attenuation) N2750/1/2A User’s Guide...
  • Page 54 Performance Data Plots Figure 35 Frequency Response (Common Mode) N2750/1/2A User’s Guide...

  • Page 55: With N2777A Solder-In Tip (10:1 Attenuation)

    Performance Data Plots With N2777A Solder-In Tip (10:1 Attenuation) Figure 36 Frequency Response (ASE) Figure 37 CMRR, Differential (10:1 Attenuation) N2750/1/2A User’s Guide...
  • Page 56 Performance Data Plots Figure 38 Frequency Response (Common Mode) N2750/1/2A User’s Guide...

  • Page 57: With N2778A Socketed Tip (2:1 Attenuation)

    Performance Data Plots With N2778A Socketed Tip (2:1 Attenuation) Figure 39 Frequency Response (ASE) Figure 40 Frequency Response (Common Mode) N2750/1/2A User’s Guide...

  • Page 58: With N2778A Socketed Tip (10:1 Attenuation)

    Performance Data Plots With N2778A Socketed Tip (10:1 Attenuation) Figure 41 Frequency Response (ASE) Figure 42 Frequency Response (Common Mode) N2750/1/2A User’s Guide...

  • Page 59: Performance Verification

    Keysight N2750/1/2A Differential Probes User’s Guide 6 Performance Verification Test 1. DC Input Resistance Test 2. Bandwidth Performance Test Record This chapter describes two procedures that are used to verify the performance of the N2750/1/2A probes. The performance verification for the probes consists of verifying the probe’s DC input resistance and bandwidth.

  • Page 60: 6 Performance Verification

    Performance Verification Table 6 Required Test Equipment (Sheet 1 of 2) Performance Test Test Equipment Recommended Model Infiniium Oscilloscope If a 90000 Q/X-Series oscilloscope is used, an N5442A precision BNC adapter is required. Digital Multimeter Keysight 33401A or equivalent). Critical specification: 2 wire resistance accuracy Vector Network Analyzer Keysight E8361A/C (2-port).
  • Page 61 Performance Verification Table 6 Required Test Equipment (Sheet 2 of 2) Performance Test Test Equipment Recommended Model Broadband Load Keysight SMA male broadband load (Keysight P/N: 1250-3745). This load is included in the N5443A PV and deskew PV and deskew fixture for InfiniiMax III.

  • Page 62: Test 1. Dc Input Resistance

    Performance Verification Test 1. DC Input Resistance Refer to the list of required equipment in Table 6 on page 60. NOTE Allow the probe to warm up for at least 20 minutes. Procedure 1 Snap the socketed tip onto the probe. The socketed tip is the easiest to use in this test.

  • Page 63: Test 2. Bandwidth

    Performance Verification Test 2. Bandwidth Refer to the list of required equipment in Table 6 on page 60. In the following procedure, the E2655B is shown in the pictures. You could also use the N5443A PV fixtures which uses a slightly different lead clamp. NOTE Allow the probe to warm up for at least 20 minutes.
  • Page 64 Performance Verification 5 On the VNA, connect 3.5 mm cables to PORT 1 and PORT 2. NOTE If the 2.5 mm or 1.85 mm cables are used, install Keysight 11901D adaptors to convert to 3.5 mm connections at the measurement plane. As with all precision connector interfaces, torque all connections using CAUTION the proper torque wrench.

  • Page 65: Measure V In Response

    Performance Verification 10 Clear all traces from the VNA’s display. Press [Meas] > S21 to display the S21 response. 11 Press [Scale] and enter the following settings for the response: Scale: ........3 dB/div Reference Level: .
  • Page 66 Performance Verification Figure 45 Probe Connected to Probe Adapter (not to scale) N2750/1/2A User’s Guide...
  • Page 67 Performance Verification NOTE Allow the probe to warm up for at least 20 minutes. f If available, use the N2787A 3D Probe Positioner to position the probe straight up and down (perpendicular) to the PV Fixture as shown in Figure Figure 46 Measurement setup for V 17 Spread the probe tip’s wires so that the tips are slightly wider than the gap...
  • Page 68 Performance Verification Figure 47 Close-Up Showing Tip Spacing and Position g Position the probe’s A tip on the center conductor as close to the edge of the conductor as possible. Position the probe’s B tip to the ground, as close to the dielectric as possible.

  • Page 69: Measure V Out Response

    Performance Verification Figure 48 Response 19 On the VNA, press [Memory] > Data > Memory to save the de-embedded input voltage trace into memory. Measure V Response 20 Disconnect the PORT 2 cable from output of the PV fixture and connect the cable to the output of the probe adapter as shown in Figure 49 on page 70.
  • Page 70 Performance Verification Figure 49 Measurement Setup for V 22 On the VNA, press [Trigger] > Single to trigger a single sweep. 23 Press [Scale] > Reference Level and adjust the reference level until the 50 MHz point (at the display’s left side) is at center screen. NOTE The reference level should be approximately –15.3 dB, but can vary a few tenths of a dB either way.

  • Page 71: Determine The Bw

    Performance Verification Figure 50 Response Determine the BW 25 Press [Memory] > Data Math > Data/Memory. This step divides the active trace (de-embedded V ) by the memory trace (de-embedded V ) to show the voltage transfer function of the probe or V 26 Press [Scale] >...
  • Page 72 N2750A: ........≥ 1.5...

  • Page 73: Performance Test Record

    A and B leads) 100 kΩ ± 2% (single-ended, between A and ground) 100 kΩ ± 2% (single-ended, between B and ground) Test 2. Bandwidth N2750A ≥ 1.5 GHz N2751A ≥ 3.5 GHz N2752A ≥ 6.0 GHz N2750/1/2A User’s Guide...
  • Page 74 Performance Verification N2750/1/2A User’s Guide...
  • Page 75 Index Index Numerics Differential setting, N2777A solder-in tip, 10, dimensions, SPICE model with N2750A, 1143A Probe Offset Control and Power disable, probe button, N2778A socketed tip, 10, Module, N2787A probe positioner, 3D probe positioner, 8, N4691B Electronic Calibration Module, E2655B PV fixture,...
  • Page 76 Single acquisition, Single Quick Action, Single-Ended A setting, Single-Ended B setting, single-ended measurements, 8, specifications, SPICE Data, 31, SPICE model, SPICE models, N2750A with N2777A tip, N2752A with N2776A tip, STOP acquisition, attaching, browser, removal, socketed, N2750/1/2A User’s Guide...

This manual is also suitable for:

N2751aN2752a

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