Technologies > Immunity > Current Spreading Scan
Amber Precision Instruments is a research-oriented EMC solution provider
Immunity/Current Spreading > Principles
Current spreading is a re-construction of spreading currents, which are usually the real problematic element that causes ESD failures. Magnetic fields are measured in time domain while currents injected to a fixed point of a DUT, converted to surface current density through post-measurement processing, and current flow is presented as a video. This is for more visualization purpose, rather than quantitative analysis.
• See the video of 'Current Spreading Principles' >
An ESD simulator can be a current injection device, but it has the notorious radiation issue, which can easily overpower the induced fields from the flowing current in a DUT. API uses a TLP as the current injection device. For more information about an ESD gun versus a TLP, click on to view the paper
Immunity/Current Spreading > Applications
● Identifying an effective clamping device placement
● Performance comparison of clamping devices
● Identifying unintended current paths
Combining CS with the ESD scan can provide powerful insight to understand DUT's behavior during ESD tests.
Immunity/Current Spreading > Required Equipment
● TLP with a triggering signal capability
Since it is measuring the fields from the DUT, EMI probes are used. API's standard EMI probe for CS is Hx-2mm. Scanning is done for both X and Y directions separate, and combined together for magnitude.
TLP with a triggering signal capability
The field measurement and current injection have to be synchronized, and thus the TLP is equipped with triggering signal port, which is 40 dB attenuated TLP HV output.
Oscilloscope with minimum 2 GHz bandwidth and 20 GSamples/sec
The rise of the TLP is < 350 pSec, and 20 GSamples/sec sampling will be enough re-constructing the rising edge of the TLP output waveform. A list of oscilloscope families that API supports is shown below. API writes the driver when a specific oscilloscope driver is not readily available in SmartScan-CS.
● KeySight (Agilent) 54580A DSO
● KeySight (Agilent) 6000 DSO
● KeySight (Agilent) 9404A DSO
● Tektronix DSA70604
● Tektronix TDS6154
● Tektronix TDS7104
● Tektronix DPO7254
● LeCroy X Stream