Tektronix P6230 Variable Bias/Offset Active Probe

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Detailed Specifications

Tektronix Catalog Cost
$395 (1985)
$420 (1989)
e-Bay Sample Prices

  • Bandwidth : DC to 1.5 GHz
  • Risetime : 230 ps
  • Attenuation : 10X
  • Input Resistance : 450 Ω
  • Input Capacitance : 1.3pF
  • Scope Input Resis : 1 MΩ or 50Ω (switchable 50Ω termination)
  • Compensation Range : ?
  • Readout Pin : Yes
  • Ground Ref : ?
  • ID Button : ?
  • Max Rated Voltage : 10 VDC
  • Recommended for ECL Probing

    The TEK P 6230 is a 1,5 GHz, low-impedance (1,3 pF), subminiature, 10X active FET probe for use with broad-band oscilloscopes.
  • The P 6230 is equipped with an internal/external 50 Ohm termination switc which allows the probe to be used on scopes having an input resistance of either 50 Ohm or 1 MOhm.
  • Bias/Offset from -5 V to +5 V (probe tip).
  • Rise time: 230 ps.
  • The probe derives its power from the probe power jack on many TEK scopes, an 1101 or 1101 A power supply.
  • With Read-Out and BNC connector.

    7A16A, 7A19, 7A24, 7A26, 7A29, 7A42 (Requires Probe Power)
    2400 Series
    585, 475, 475A, 464, 466
    DC5010, SI5010, DC503A, DC504, DC505A, DC509, DC508A
    The P6230 is a 1.5 GHz, low-impedance, subminiature, 10X active probe for use with broad-band oscilloscopes. The P6230 is equipped with an internal/external 50 Ω termination switch whith allows the probe to be used on scopes having an input resistance of either 50 Ω or 1 MΩ. A coding pin on the BNC connector activates the Volts/Division reading by 10X on oscilloscopes equipped with this feature so that the correct deflection factor at the probe top is indicated.

    The compensation box of the P6230 houses an active circuit which provides a variable voltage at the probe tip. This voltage is used to minimize probe-loading effects. The voltage available at the tip of the P6230 spans the range from minus five volts to plus five volts, allowing the probe to minimize loading effects on most logic families that are in use today.

    The P6230 acts as a standard 500 Ω passive voltage probe with the additional capability of having an adjustable tip "nulling voltage." This feature reduces the dc-loading effects on the probe when it is used to measure signals whose mid-voltage value is other than zero volts, or in circuits where the termination impedance is returned to other than ground level. The Input Bias/Offset Voltage may be adjusted so that at a particular test-signal voltage both ends of the probe input-resistor are at equal potentials and no current is flowing through the resistor.

    ECL logic is most commonly operated from a -5.2 V supply with Vcc connected to ground. The output of an ECL gate is the emitter of an NPN emitter follower stage. The output is pulled down to a negative supply (about -2 V) with an external resistor (50 Ω to 100 Ω). Since speed is a major consideration in ECL designs, the interconnections between gates are often transmission lines, and the pull-down resistor doubles as a line termination.

    If a standard 500 Ω, 10X probe without the input Bias/Offset feature were used to examine an ECL output, the probe's 500 Ω resistance to ground would form a voltage divider with the gate's output-termination resistor. This divider can cause distortion of the output signal levels, shift the dc operation point of the output transistor, and reduce the gate's noise margin.

    The dc-load nulling capability of the P6230 helps to solve this problem. By adjusting the Input Bias/Offset Voltage to the ECL low level or to the termination voltage, the only effect of the probe resistance will be a small decrease in the ECL output-termination resistance. The effect of the probe on output voltage levels is negligible.

    The probe derives its power from the probe power jack on many Tek scopes or an 1101 or 1101A Power Supply.

    (excerpt from the 1985 and 1989 Tektronix catalogs)

    Attenuation :10X
    Input Resistance :450 Ω
    Input Capacitance :1.3 pF
    Bandwidth (-3 dB) :DC to 1.5 GHz
    Risetime :230 ps
    Maximum Input Voltage :10 VDC

    Probe will operate within specifications over the following ranges:
    Temperature : -0° to +50°C. (+32°F to +122°F)
    Humidity : Five cycles (120 hr) 95% to 97% at 30°C to 60°C.
    Altitude : To 15,000 feet.

    (excerpt from 1985 Tektronix catalog)

    Tektronix Catalog CostLow BidHigh Bidaverage
    $395 (1985)
    $420 (1989)
    $25.48 12/19/02 #3100304105 united13 (6 bids)