Atlas Si – insertion loss test made simple for PCB fabricators – supports SET2DIL test method for differential insertion loss

Testing transmission line losses in the production environment

Polar Atlas software enables PCB fabricators to test PCB transmission line losses in a tightly controlled production environment. Atlas employs mathematical processing techniques to extract frequency dependent loss characteristics when used in conjunction with suitably designed test coupons and Atlas precision GHz probe assemblies.

Atlas software interfaces– with industry standard Tektronix DSA8200 oscilloscope tdRs*. Atlas supports SET2DIL (Single-ended tdR to Differential Insertion Loss) test methodology for extraction of differential insertion loss from a single ended test and suitably designed coupon.**

At GHz frequencies the measurement of PCB transmission line losses become inherently more challenging and in order to extract accurate measurements the signal integrity of the whole measurement system needs to be taken into account, from measurement instrumentation through the signalling cable and probe interconnect and finally through the launch structure of the test coupon and test trace itself.

The Atlas loss measurement system

Atlas software is designed to assist PCB fabricators in the accurate and repeatable measurement of PCB transmission line losses in a PCB production environment.

Atlas software is designed for interfacing with the Tektronix DSA8200 tdR* with 80E04 tdR* sampler heads and optional Polar CGen Si insertion loss coupon generator. Probe and interface cables will depend on those specified by your OEM, please contact Neil Chamberlain for more assistance.

Users employing Atlas for SET2DIL measurements should use (as of January 2012) the GGB Picoprobe type 40A-GSSG-450-TLD probe* (complies with IPC spec. IPC-TM-650 Method 2.5.5.12A.) Please contact Neil Chamberlain for more information regarding probes and cables in this application.

* Accuracy of 3^rd party probe launch vehicles is the responsibility of the end user.

Unlike test of lossless controlled impedance traces where measurement was broadly independent of system rise time, the test of lossy lines means that system rise time becomes critical to quality high frequency measurements. Atlas tracks system risetime and monitors the system bandwidth. Atlas uses mathematical techniques to extract insertion losses on differential and single ended PCB traces.

Test methods for loss measurement

The industry has not yet settled on one common method for loss measurement, and the technique selected will normally be agreed between the OEM and the fabricator. Atlas includes Polar methods for extraction of insertion loss, along with the recently proposed SET2DIL method for extracting differential insertion loss from a single ended measurement.

New high speed silicon families, such as Xaui, PCI Express Gen2.0, USB 3.0 and other high speed silicon increasingly deploy high speed differential signalling techniques that push system speeds above the traditional ceiling for FR4. Advanced signal processing is used to recover the signals from PCB traces which will lose most of the signal energy in transit across the PCB. Designers need to ensure the losses remain within the signal extraction capabilities of their chosen chipset. This has led to an industry requirement for a consistent test capability for insertion loss.

Atlas GHz test software is also capable of traditional lossless controlled impedance test, however Polar recommends the CITS900s as your primary solution for lossless impedance test owing to the lower inherent running costs. (The fast risetimes dictated to measure insertion loss at multi GHz speeds mean that ESD control needs to be of the highest level in an Atlas environment to minimise the running costs – precision fast rise time tdR sampling heads are sensitive and easily damaged by ESD)

PC Specifications: See Application Note AP605 for Atlas software system requirements

Licensing: FLEXlm hardware key, with annual or full licence plus Polarcare maintenance.

Availability: Atlas Si 2012 edition is now released and shipping.

Contact: Neil Chamberlain Signal Integrity Product Manager

Polar products for insertion loss test and modeling include:

• Si9000e lossy line field solver
• Speedstack Si layer stackup design and documentation system
• Speedflex HDI Si layer rigid flex stackup design and documentation system
• CGen Si insertion loss test coupon generator
• Atlas Si GHz insertion loss test system.

* Supplied separately

** Optional insertion loss coupon generator CGen Si.