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    GaN “VRM+PDN Validators” in different formats to support different current levels


    10A-50A – Water-Cooled Probe Head Stepper



    • GaN-enabled - Orders of magnitude faster edge speeds than other solutions
    • Vastly higher power density/currents – up to 100% duty cycle
    • Transients on the order of the package bandwidth of your VRM
    • Enables true PDN validation and Power Integrity noise performance
    • Precise and repeatable load current control allows you to characterize and validate power rail crosstalk, thermal performance, and EMI
    • Enable your Power Distribution Network to be validated BEFORE the expensive processor/digital load is connected
    • Vastly outperforms traditional electronic loads and other load stepper solutions
    • Enables long dwell times for slow load line loop testing
    • Digital control module with Complete Load Current Control
    • Pseudo random,Long dwell, Long Pattern, Sine, Digital Slew, Exponential, Fast burst



    • < 10nS edge speed and DC operation for max average power
    • Probe tip, liquid-cooled probe and refrigerated-liquid-cooled in-socket
    • Up to 125W/in2
    • Highly miniaturized time-matched GaN Load Cells
    • Digital or Analog control of Digital or Analog Load Cell


    Water-Cooled Probe Head-Based Solution

    • Browser probe style
    • Up to 50A (peak and average)
    • Direct control of load current profile
    • Enables infinite dwell time for slow load line loop testing and thermal (TDP) testing
    • Verify large signal control loop stability
    • Load emulation &transient testing for FPGA, AI, Big Data, Graphics and Servers



    • Power Supply Testing and Measurement
    • VRM and PDN Validation
    • Rail noise evaluation
    • Transient load step (large signal)
    • SPICE/ADS State Space Average Model Development
    • Large-signal control loop stability andInput filter stability
    • Thermal (TDP) testing
    • IC Package evaluation


    What's included:

    Water-Cooled Solution (Model S50)

    • Water-Cooled Stepper Probe with six (6) customized load steps
    • Cooling unit with cooling fluid


    Transient Testing
    Transient load current step testing is a critical part of power system design, test, and verification. No matter the architecture, design make-up, or power levels, transient testing is key to evaluating many aspects including power integrity, power distribution network (‘PDN) validation, Voltage Regulation Module (‘VRM’) stability and transient response, noise, large-signal control loop stability, input filter stability, load emulation, thermal (TDP) testing, and IC package performance.

    Picotest’s line of transient steppers enable testing of very fast load current transitions, high peak and average power, via multiple form factors that previously were unavailable or impractical to accomplish. In particular, demanding low-voltage, high-current applications including those found in data centers, AI, graphics, EV, and servers can now be tested, including crosstalk, thermal performance and EMI, long before the final ASIC is even available.

    The power distribution networks that provide power to advanced digital loads such as CPUs, GPUs, ASICs, FPGAs, and other custom ICs can now be validated before the costly ICs are exposed to any power system related unknowns.

    Product Selection
    The product line provides load step testing orders of magnitude faster and higher than previously available. The S50 has the following product levels are available based on load current 10A-50A. Picotest offers both open and closed-loop load current control options. The open loop stepper is essentially a signal level voltage controlled switch that opens or closes a path from the power rail through a GaN FET and custom resistor. So, while the probe can be moved to rails of different voltages and the step current will vary based on the power rail voltage. The baseline load current is set at the time of purchase for a specified voltage-current combo resulting in fixed resistor values in the probe. 

    The S50 10A-50A solution is a water-cooled browser-style probe format with 6 user pre-defined current steps (6-bit logic level control). Again, the current is dependent on the voltage of the power rail.

    This step loader replaces the ASIC that normally loads the power rails, allowing thorough power rail validation including load line testing, large signal impedance, thermal testing, crosstalk assessment and EMI. This solution allows programmed and custom load current profiles from 0 to 50A

    Water-Cooled Browser Probe (S50)
    This is a hand held or probe stand held browser probe. It behaves in a similar way to the P2105A. It comes with a water-cooler that enables the load current/power density to be higher. The current step (current sinking into the positive pin) is controlled by a control wire pair. This is a 6 bit control bus with 3.3V or 5V logic level. There are 6 switches and each can be turned on or off and each can have a level set at the time of manufacturing. So, there are 6 discrete levels that can be switched individually or combined to achieve up to 50Amps.

    Delivery: 4-6 weeks, depending on resistor selection. Resistor selection and PDN voltage must be specified at checkout.


    Please e-mail if you have questions about the resistor selection.


    Application Notes
    Evaluating Voltage Regulator Stability Using Step Load Testing 

    Picotest Water-Cooled Head Stepper <50A (S50)

    • Edge Rate (R/F time) <500ps switching *
      Repetition Rate DC-50MHz (Limited by average power and dwell time)
      Control User Supplied - Digital logic generator or Micro-controller (3.3V-5V)
      Maximum Dwell Time Up to 100%
      Input voltage rating Based on custom resistor *
      Output current rating Based on resistor up to 50A
      Wattage <50W avg.
      Voltage 0.8V - 72V
      Connector Type SMPM pulse, spring tip


      * Final signal edge speed is dependent on the load board design, voltage, and current.Solution is single level (On/Off). Resistance is set at the time of manufacturing.


      *Step Load current is a set by PDN voltage, and step load probe resistor value. An example is provided below.


      *This probe has 6 step load values that need to be specified, where the total possible current is when all step loads are turned 'ON'.


        PDN Voltage Step Load Resistor Step Current
      step #1 1V 1 Ohm 1A
      step #2 1V 0.5 Ohm 2A
      step #3 1V 0.25 Ohm 4A
      step #4 1V 0.125 Ohm 8A
      step #5 1V 0.1 Ohm 10A
      step #6 1V 0.040 Ohm 25A
          Total Step Load Current 50A

      The S50 probe can be built using any standard 1% tolerance resistor values and even customer resistor values.

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