Impedance Checks
The Voyager M310P, M310e, and M4x contain a circuit designed specifically for performing the impedance checks required by the Type-C Functional test specification. It provides a simple pass/fail result, so we will provide further detail on how it works here.
Safe State Electrical Requirements
Impedance to ground on SBU pins must be < 4 MΩ
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Switch a 10 MΩ pull-up to 5 V and a 1 MΩ pull-down to ground onto the SBU line
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Allow 10 ms for the voltage to settle
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Check the voltage with a comparator, and consider the line safe it’s less than 400 mV (This allows for a small amount of tolerance)
SBU Termination Requirements
Impedance must be ≥ 950 kΩ, functionally equivalent to an open circuit
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Switch a 10 MΩ pull-up to 5 V onto the SBU line
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Allow 10 ms for the voltage to settle
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Check the voltage with a comparator, and consider the line open if it’s greater than 400 mV (This allows for a small amount of tolerance)
Note that you should not use an ohmmeter to measure in-circuit impedance. Ohmmeters work by sending a constant known current and then measuring the voltage drop. If the component to be measured is not removed from the circuit the current is split into all available circuit paths and will not result in an accurate measurement.
Supported External Hardware
Electronic Loads
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B&K Precision 8600/B (if PDP is 140 W or less)
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B&K Precision 8601/B
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B&K Precision 8602/B (if PDP is 140 W or less)
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B&K Precision 8610/B
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B&K Precision 8612/B
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B&K Precision 8614/B
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B&K Precision 8616/B
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ITECH IT8811 (if PDP is 140 W or less)
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ITECH IT8812
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ITECH IT8812B (if PDP is 140 W or less)
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ITECH IT881C
Power Supplies
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B&K Precision 9202/B
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B&K Precision 9205/B
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B&K Precision 9206/B
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ITECH IT6722A