Outstanding TDR/TDT Capabilities when hand probing is required using the GigaProbes™ 30Ghz 100/50 ohm TDR probes. The WaveExpert Time Domain Reflectometry (TDR) is an essential tool for signal integrity measurements of today's high-speed designs. Impedance discontinuities in PCB's connectors, etc. can reduce the bandwidth supported by the channel. These critical measurements can be easily made, either as voltage reflections or as impedance measurements, using the TDR feature on the WaveExpert Series. The available TDR module (ST-20) includes a step generator that produces a fast step (typical rise time of 20 ps) to quantify sub-millimeter discontinuities in PCB's, backplanes, interconnects, etc.
Single-ended and Differential measurements
Fast Step (20 ps Rise Time)
True Impedance profiling
Sub-millimeter measurement resolution
Advanced TDR calibrations such as OSL (Open Short Load) to remove effects of cables, fixtures, etc.
TRUE differential drive to DUT
Automated Step and Sampler Deskew
REALTIME Accurate S-parameter measurements to 20 GHz
Data Output in Voltage, Impedance, or S-parameter (SnP) format
Use the LeCroy "FreeHand" Probe holder to hold the GigaProbes(tm) in place to free up your hands to operate the LeCroy WaveExpert TDR system
DEVICE TEST BOARD IMPEDANCE AND S-PARAMETERS ANALYSIS
TDR test setup schematic. Probe the PCB test pads without test socket to base line the signal integrity performance (TDR & S-parameters). Put the socket back on and probe the pogo pins to measure the impact on impedance and S-parameter return-loss.
Probe test socket footprint with WaveExpert in differential TDR mode connected to the Gigaprobes™. Attach two SMA cables to the SMA Tx or Rx output to the scope sampling modules. This configuration allows for making TDR/TDT and real-time SDD11/21 S-parameters to 20GHz
Differential TDR plot without test socket. Click on image for full size view.
Complete Realtime TDR/TDT and Insurtion/Return Loss Sparameters test setup
Realtime SDD11 and SDD21 S-parameters from the Test socket pogo pins to I/O SMA connectors
This TDR/TDT and SDD11/21 real-time plot verify the transmission path from the pogo pins within the socket and the interconnect components before the board is populated with active devices. If the rise time of the interconnect path is not 5-7 faster than the signal rise time, it degrades the eye diagram. Notice excessive rise time slop indicating excessive interconnect signal loss through this test board. Use cursers to measure the actual bandwidth where SDD11 & 21 crosses to determine bandwidth. The LeCroy WaveExpert 100,000 horizontal sampling points increase the impedance and Delta F S-parameter resolution on long transmission lines.
LeCroy Wave Expert 100 Screen image showing impedacne measurements on a trace using the GigaProbes
PACKAGE TESTING
Device Package Impedance and Failure Analysis Using LeCroy Wave Expert 100, GigaProbes in 50 ohm configuration installed in a Probing Solutions Manipulator and the Device held down on a vacuum chuck.
For package testing with the LeCroy WaveExpert, order the GPMMA adapter for your Gigaprobes(tm) from DVT Solutions, LLC. The Cascade Ez-probe can be ordered from LeCroy.
The LeCroy WaveExpert 18ps TDR pulser provides the resolution to measure single and differential impedance in package testing. The fast TDR rise time is also a benefit in locating opens/shorts for package failure analysis. Add a vacuum chuck to hold down the package and you have a total package and FA test system. Contact your LeCroy account manager for a demo.
TDR Measurement of Package Trace Path
Click on this LINK for more training on TDR and S-parameter measurements and get the full application presentation of the above TDR applications.
For more information call your local LeCroy Account Manager for a demonstration on your interconnect design or visit LeCroy.com
Copyright 2006 Brian Shumaker DVT Solutions 650 743-5669
