xx P6250 & P6251 500 MHz and 1 GHz High Voltage Differential Probes ZZZ Technical Reference www.tektronix.
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Table of Contents Table of Contents General Safety Summary . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . . . Service Safety Summary . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . Preface .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. .
Table of Contents ii P6250 & P6251 Technical Reference
General Safety Summary 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. While using this product, you may need to access other parts of a larger system. Read the safety sections of the other component manuals for warnings and cautions related to operating the system.
Service Safety Summary Terms 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. Symbols and Terms on the Product These terms may appear on the product: DANGER indicates an injury hazard immediately accessible as you read the marking.
Preface Preface This is the Technical Reference for the P6250 & P6251 differential probes. This manual provides specifications and performance verification procedures for the probes.
Preface vi P6250 & P6251 Technical Reference
Specifications Specifications The specifications in the following Tables apply to a P6250 or P6251 differential probe installed on a Tektronix TDS5000B oscilloscope. When the probe is used with another oscilloscope, the oscilloscope must have an input impedance of 50 Ω and a bandwidth of 1 GHz. The probe must have a warm-up period of at least 20 minutes and be in an environment that does not exceed the limits described. (See Table 1.
Warranted Characteristics Warranted Characteristics Warranted characteristics describe guaranteed performance within tolerance limits or certain type-tested requirements. (See Table 1.) Warranted characteristics that have checks in the Performance Verification section are marked with the symbol. Table 1: Warranted electrical characteristics Specification P6250 P6251 Differential signal range (DC coupled) ±4.25 V(DC + peak AC); 3 V RMS ±42 V (DC + peak AC); 30 V RMS ±4.
Typical Characteristics Typical Characteristics Typical characteristics (Tables 2 and 3) describe typical but not guaranteed performance for both probes. Table 2: Typical electrical characteristics Differential input resistance, DC coupled 1 MΩ Common mode input resistance 500 kΩ Differential input capacitance <1.0 pF at 1 MHz Common-mode input capacitance <2.0 pF per side at 1 MHz Harmonic distortion ≤1.5% measured using 495 mVRMS (or 1.
Typical Characteristics Figure 2: Typical bandwidth (P6251) Figure 3: Typical rise time (P6250) 4 P6250 & P6251 Technical Reference
Typical Characteristics Figure 4: Typical rise time (P6251) Figure 5: Typical Common-Mode Rejection Ratio (P6250) P6250 & P6251 Technical Reference 5
Typical Characteristics Figure 6: Typical Common-Mode Rejection Ratio (P6251) Figure 7: Typical input impedance versus frequency 6 P6250 & P6251 Technical Reference
Typical Characteristics Table 3: Typical mechanical characteristics Dimensions, input connection 0.63 mm (0.025 in) square pin on 2.54 mm (0.100 in) centers Dimensions, control box 82 mm × 41 mm × 26 mm (3.2 in × 1.6 in × 1.0 in) Dimensions, probe head 86 mm × 11 mm × 6.3 mm (3.4 in × 0.45 in × 0.25 in) Dimensions, output cable 1.22 m (48 in) Unit weight (probe only) 163 g (5.
Nominal Characteristics Nominal Characteristics Nominal characteristics (Table 4) describe guaranteed traits, but the traits do not have tolerance limits. Table 4: Nominal electrical characteristics 8 Input configuration Differential (two inputs, + and - ), with case ground Output coupling DC coupling Voltage ranges 4.
Probe Tip Adapter Specifications Probe Tip Adapter Specifications This section describes the characteristics of the adapters that are included in your accessory kit. The adapters are listed in order of performance, beginning with the fastest. You will obtain the best probe performance by connecting the probe directly to square pins on your circuit. However, as test points are not always as convenient, these adapters make taking measurements easier while maintaining the best signal fidelity. NOTE.
Probe Tip Adapter Specifications Longhorn Adapter Tektronix part number: 016-1780-xx Bandwidth: >1.0 GHz 10/90 Rise time: <350 ps This adapter has sharp, adjustable pins that can span up to 0.35 inch apart. They are useful for probing small circuit board features such as vias and narrow traces.
Probe Tip Adapter Specifications 1” Solder Down Adapter Tektronix part number: 196-3504-xx Bandwidth: >820 MHz 10/90 Rise time: <430 ps Use this adapter to provide easy access to test points that you frequently check, or that may be difficult to probe with other methods.
Probe Tip Adapter Specifications 3” Solder Down Adapter Tektronix part number: 196-3505-xx Bandwidth: >550 MHz 10/90 Rise time: <635 ps Use this adapter on test points that you frequently check that do not have square pins or other convenient connections. Solder the leads to your test points, spaced up to 5.5 inches apart. CAUTION.
Probe Tip Adapter Specifications Y-Lead Adapter Tektronix part number: 196-3434-xx Usable Bandwidth: <250 MHz Calculated rise time: 1.4 ns Use this adapter for DC and low-frequency measurements. The socket ends plug onto square pins, component leads, and the MicroCKT test tip adapters included with the probe.
Probe Tip Adapter Specifications MicroCKT Test Tip Adapter Tektronix part number: 206-0569-xx Usable Bandwidth: <100 MHz Calculated rise time: 3.5 ns Use the microCKT test tip adapters with the Y-lead adapters. Due to the length of these adapters, they are only recommended for DC and low-frequency measurements.
Performance Verification Performance Verification Use the following procedures to verify the warranted specifications of the P6250 and P6251 Differential Probes. Before beginning these procedures, photocopy the test record and use it to record the performance test results. (See Table 7 on page 35.) The recommended calibration interval is one year.
Performance Verification Required Equipment Table 5 lists the equipment required to perform the performance verification procedure. The types and quantities of connectors may vary depending on the specific equipment you use. NOTE. The procedures in this section require a network analyzer to perform the analog bandwidth and CMRR tests. Alternative procedures that do not require a network analyzer are included in this manual.
Performance Verification Attenuator 100 X, 50 W, BNC connector Aeroflex 60B50W-40dB Spring-loaded probe tip pins P7260 probe accessory Tektronix 016-1917-xx Special Adapters Some of the adapters used in these procedures are available only from Tektronix. These adapters are described on the following pages. 1103 Power Supply The 1103 power supply is used to power the probe under test.
Performance Verification BNC-to-Probe Tip Adapter The BNC-to-probe tip adapter, Tektronix part number 067-1734-xx, provides connections for signal sources and probe test points. (See Figure 8.) The adapter breaks out the signal input on the BNC connector to pairs of square pins, one each for common-mode and differential-mode connections. 1. BNC connector for input signals 2. Differential Mode (DM) square-pin pair 3.
Performance Verification Preparation CAUTION. To prevent damage to the 80E04 sampling head, plug in the sampling head and then power on the TDS8000 oscilloscope. Prepare the equipment as follows: 1. Connect the 80E04 sampling head to channel 1 of the sampling oscilloscope and then power on the TDS8000 oscilloscope. 2. Plug in and power on all test equipment. (See Table 5 on page 16.) 3. Connect the probe to channel 1 of the 1103 power supply. 4.
Performance Verification DC Attenuation Accuracy This test checks the probe gain by measuring known voltages with a multimeter. The probe is then used to measure the same voltages, and then a comparison calculation is made. Preparation 1. Press the VAR/0v button to the off position on the 1103 power supply (the button is not lighted). 2. Set the probe to the 42 V range (÷ 50), DC reject off, and full bandwidth. 3. Connect the MicroCKT test tips to the DC source.
Performance Verification 14. Calculate the attenuation twice, using the values from the measurements as follows: (Vin1 - Vin2) ÷ (Vout1 - Vout2) and (Vin2 - Vin3) ÷ (Vout2 - Vout3). 15. Verify that the attenuation is in the range of 49 to 51. Record the results in the test record. 4.25 V Range (÷ 5). 16. Set the input voltage on the DC source to approximately 4.2 V ±50 mV. Record the actual voltage as Vin1. 17. Change the probe voltage range to 4.25 V (÷ 5). 18. Record the output voltage as Vout1. 19.
Performance Verification Differential Signal Range This procedure directly verifies the differential signal range and indirectly verifies the common-mode signal range. This procedure uses the setup from the previous test. Verification 42 V Range (÷ 50). 1. Set the probe to the 42 V range (÷ 50), DC reject off, and full bandwidth. 2. Set the input voltage on the DC source to 0 V, and verify that it is 0 V with the multimeter. 3. Measure the probe output voltage as Voffset.
Performance Verification 14. Set the probe to the 4.25 V range (÷ 5). 15. Measure and record the output voltage as Vout. 16. Calculate attenuation using the formula in step 6. 17. Verify that the attenuation is in the range of 4.75 to 5.25. Record the results in the test record. 18. Reverse the Y-lead connection on the probe to reverse the polarity of your following measurements. 19. Measure and record the output voltage as Vout. 20. Calculate attenuation using the formula in step 6. 21.
Performance Verification Analog Bandwidth The following steps prepare the network analyzer for measuring bandwidth and CMRR. The actual settings may vary with different models of network analyzer. Refer to the user documentation supplied with the network analyzer for details on performing these steps. NOTE. An alternative procedure for testing the analog bandwidth and CMRR without a network analyzer is available. Preparation The 1103 power supply can operate two probes.
Performance Verification Verification 4.25 V Range (÷ 5). NOTE. Do not remove the cable end that is connected to the network analyzer. Connect the cable to the BNC-to-probe tip adapter. 1. Disconnect the port 1 cable from the 1103 channel 1 input connector and connect to the BNC-to-probe tip adapter. 2. Move the probe from the 1103 channel 2 to channel 1 input connector. 3. Set the probe for ÷ 5 attenuation, full bandwidth, DC reject off. 4.
Performance Verification 42 V Range (÷ 50). 8. Set the probe to the 42 V range (÷ 50). 9. Change the reference value on the network analyzer to keep the plot on screen (–34 dB). 10. Using the marker (if equipped), measure the output amplitude at 500 MHz for the P6250 or 1 GHz for the P6251. 11. Verify that the amplitude is greater than –37 dB. (Subtracting the –34 dB of probe attenuation in the 42 V range from the –37 dB target value yields the –3 dB limit.) Record the results in the test record. 12.
Performance Verification Common Mode Rejection Ratio If verification of analog bandwidth was not performed, or the calibration of the network analyzer has been altered, perform the calibration and normalization steps in the Preparation section of the Analog Bandwidth verification. In this test, you first plot the differential mode gain, and then the common mode gain. Next, using the math function on the network analyzer, you create a plot that represents the reciprocal of the CMRR.
Performance Verification Rise Time This procedure verifies that the probe meets the warranted rise time specification of the 4.25 V range (÷ 5). Two rise times are measured; the test system alone, and then the test system with the probe included. The probe rise time is calculated using the two measurements. This test uses the 80E04 as a fast rise time signal source. The second channel of the 80E04 sampling head is used to take the measurements.
Performance Verification 6. Set the Channel 1 sampling head to TDR mode: press the SETUP DIALOGS button and select the TDR tab. Refer to the following illustration. 7. Set the Channel 1 (C1) Polarity to positive (rising). 8. Set the Preset of Channel 1 on. TDR Preset sets Internal Clock in the Trigger menu, turns on the TDR Step in the TDR Setups menu, turns on the channel and selects the acquisition Units in the TDR Setups menu, and sets the horizontal scale, position, and reference.
Performance Verification Test System and Probe Rise Time 14. Disconnect the SMA cable and BNC adapter from the Channel 1 input of the 1103 power supply. 15. Connect the SMA cable to the BNC-to-probe tip adapter. 16. Connect the probe to the 1103 power supply channel 1 input and set the attenuation to ÷ 5. 17. Turn off the offset control on channel 1 of the 1103 power supply. 18. Connect the probe to the DM test points on the BNC-to-probe tip adapter. 19.
Performance Verification 23. Using the test system rise time (ts ) that you measured in step 12, and the test system and probe rise time (ts+p ) that you measured in step 21, calculate the probe-only rise time using the formula shown. Example: 24. Record the calculated probe rise time on the test record. This completes the performance verification. An optional rise time check for the 42 V range (÷ 50) follows.
Performance Verification High Voltage Rise Time Check (Optional) Use the following optional test to check the probe rise time on the 42 V range (÷ 50) setting. WARNING. Burn hazard exists. The 50 W termination used in this test becomes hot if the duty cycle of the pulse generator is higher than 10%. Use caution when locating the termination in your test setup. Test System Rise Time 1. Connect the 80E04 sampling head to the sampling oscilloscope. 2. Connect an SMA cable to Channel 2 on the sampling head.
Performance Verification 8. Connect a short SMA cable from the other SMA connector on the probe calibration fixture to the high voltage output connector on the pulse generator. 9. Connect the trigger out from the pulse generator to the trigger in on the sampling oscilloscope. WARNING. To reduce the risk of electric shock, do not exceed 42 Vpk on the pulse generator. Use caution when making measurements. 10. Turn on Channel 2 and set the vertical scale to 100 mV/div. 11.
Performance Verification 34 P6250 & P6251 Technical Reference
Performance Verification Table 7: Test Record Probe Model/Serial Number: _____________ Certificate Number: _____________ Temperature: _____________ RH % : _____________ Date of Calibration: _____________Technician: _____________ Performance test Minimum Measured/Calculated Maximum DC attenuation accuracy 42 V range (÷ 50) 4.25 V range (÷ 5) 49 4.9 _____________ _____________ 51 5.1 Differential signal range 42 V range (÷ 50) with connections reversed 4.
Performance Verification 36 P6250 & P6251 Technical Reference
Performance Verification Alternate Verification Procedures This section contains alternate procedures for verifying the following specifications: Analog bandwidth Common mode rejection ratio Use these alternate procedures only if you cannot obtain a network analyzer. Equipment Required for Performance Verification Table 8: Test equipment Description Minimum requirements Example product Sine wave generator (preferably a synthesizer) 0 dBm to 20 dBm from 1 MHz to 1 GHz.
Performance Verification Preparation This setup is identical to the network analyzer setup in the main procedure, except that the synthesizer and spectrum analyzer replace the network analyzer. Allow all test equipment to warm up for 20 minutes in an environment that is within the environmental conditions listed in the specifications section. Prepare the equipment as follows: 1.
Performance Verification Analog Bandwidth Normalize the Setup 1. Set the synthesizer for 500 MHz/10 dBm for P6250 probe and 1 GHz/10 dBm for the P6251 probe. 2. Set the spectrum analyzer: Center frequency at 500 MHz for the P6250 probe, and 1 GHz for the P6251 probe. Span to 10 MHz. Resolution bandwidth to auto. Reference level to 10 dBm. Vertical sensitivity to 2 dB/div. 3. Record the level displayed on the spectrum analyzer. (This level represents the synthesizer output minus the signal path loss.
Performance Verification Verification. 4. Disconnect the BNC cable from the BNC connector in the probe socket on the 1103 power supply. 5. Connect the BNC cable to the BNC-to-probe tip adapter. 6. Connect the probe into the probe socket on the 1103 power supply. 7. Connect the probe tip to the DM pins of the BNC-to-probe tip adapter. 8. Set the probe to 4.25 V range (÷ 5), DC reject off, full bandwidth. 9. Adjust the reference level of the spectrum analyzer to display a signal on screen. 10.
Performance Verification This level must be within 17 dB of the level that you recorded in step 3. For example, if the reference level from step 3 is 9 dBm, and the level that you measured in this step is -7 dBm, then the difference between the two measurements is 16 dBm, which is within the probe specification. 11. Set the probe to the 42 V range (÷ 50). 12. Change the reference level of the spectrum analyzer to -24 dBm. 13. Record the level displayed on the spectrum analyzer.
Adjustment Procedures Adjustment Procedures These procedures are for use by qualified service personnel only. Refer to the service safety summary at the beginning of this manual before servicing this product. WARNING. To avoid injury from electric shock, do not touch exposed connections. Use care when servicing equipment that is powered on. Dangerous voltages or currents may exist in this product. Disconnect power and test leads before removing protective panels.
Adjustment Procedures Equipment Required for Adjustment Procedure In addition to the equipment required to perform the performance verification, the adjustment procedures require the equipment listed in Table 7.
Adjustment Procedures Offset (Preliminary) NOTE. Do not attempt to adjust offset directly on an oscilloscope equipped with a TekProbe Interface. These oscilloscopes utilize a closed loop compensation system for gain and offset which will interfere with the manual adjustment of the probe. 1. Connect the probe as shown above, with the probe tip connected to the DM pin of the BNC-to-probe tip adapter. 2. Set the DMM to DC volts, 200 mV or 300 mV range. 3.
Adjustment Procedures Gain 1. Setup the equipment as shown in following illustration: a. Remove the BNC to probe tip adaptor from the probe input. Insert the Y-lead adaptor into the probe tip. b. With MicroCKT test tip, connect the red lead to the power supply positive terminal, and the black lead to the power supply negative terminal. c. With MicroCKT test tip, connect a ground lead from the probe case ground to the negative terminal of the power supply. d.
Adjustment Procedures 9. Adjust the power supply to output approximately 7 V. 10. Adjust the ÷ 50 gain adjustment until the DMM measuring the output reads 1/50 of the same voltage (≈140 mV) as the DMM monitoring the input within ± 5 mV. 11. Keep the probe output connections for the next step. 12. Disconnect the probe head from the power supply. Offset (Final) NOTE. The offset and gain adjustments interact. 1. Repeat steps 1 through 6 of the Offset (preliminary) procedure. 2.
Adjustment Procedures 2. Set the probe to ÷ 5 attenuation, 5 MHz bandwidth, DC reject off. 3. Set the function generator to square wave, 1 ms period (1 kHz frequency), approximately 4 V pk-pk, (2 Vpk). 4. Set the oscilloscope to display channel 1. Set channel 1 to DC and 50 Ω input impedance (or use external terminator), 2 mV/div. Set the time/division to 10 s/div. Set the trigger source to external (or Channel 2) Set the acquisition mode to average 8 to 10 acquisitions.
Adjustment Procedures AC CMRR 1. Change the function generator to sine wave. 2. Set the frequency of the function generator to 1 MHz and the output amplitude to approximately 4 V pk-pk, (2 V peak). 3. Set the probe to ÷ 5 attenuation, 5 MHz bandwidth, DC reject off. 4. Change the scope horizontal setting to 100 ns/div. If necessary, adjust the channel 2 volts/div and trigger level for a stable trigger. 5. The displayed sine wave is the common mode feedthrough.
Maintenance Maintenance This section contains maintenance information for the P6250 and P6251 differential probes. Inspection and Cleaning Protect the probe from adverse weather conditions. The probe is not waterproof. CAUTION. To prevent damage to the probe, do not expose it to sprays, liquids, or solvents. Do not use chemical cleaning agents; they may damage the probe. Avoid using chemicals that contain benzine, benzene, toluene, xylene, acetone, or similar solvents.
