W2635A and W2636A DDR3 BGA Probe Adapter for Infiniium Oscilloscopes

The Keysight Technologies, Inc. W2635A and W2636A DDR3 BGA probe adapters provide signal access to the clock, strobe, data, address and command signals of the DDR3 BGA package for making electrical and timing measurements with an Infiniium oscilloscope. The DDR3 JEDEC¹ specification (JESD79-3C) is defined at the DRAM ballout, and the ballout is difficult to access. The BGA probe adapter provides direct signal access to the BGA package for true compliance testing.

The W2635A and W2636A DDR3 BGA probe adapters are soldered in between the DRAM and PC board or DIMM raw card where the DRAM would normally be soldered. They are designed with the PCB or DIMM footprint on the bottom side and the DRAM footprint on the top side. The BGA adapter passes the signals from the memory controller chip and DRAM directly to the top side of the BGA probe adapter where they can be accessed with oscilloscope probes.

Buried resistors placed at the signals inside the BGA probe adapter connect the probed signals to solder pads designed to work with Keysight InfiniiMax E2677A, N5381A, N5425A, and N5426A differential solder-in probe heads. These resistors isolate the DDR3 signal and the probe loading effect. This design minimizes capacitive loading of the probe heads and allows high-speed operation without impact on signal integrity.

Probing at the right location is also an important consideration for DDR3 measurement. Many designs have vias or designed-in probe points, but they do not always produce good signal integrity. Probing at the wrong location could cause signal reflection, resulting in non-monotonic edges. This will cause error in your tests such as slew rate, setup and hold time measurements.

When used with Keysight’s U7231A DDR3 compliance test application, the BGA adapter provides a fast and easy way to test, debug and characterize your DDR3 designs. The tests covered by the U7231A software are based on the JEDEC (JESD79-3C) DDR3 SDRAM Specification. The test application offers a user-friendly setup wizard and a comprehensive report that includes margin analysis.

Installing the DDR3 BGA probe adapter

The W2635A and W2636A DDR3 BGA probe adapter is installed by soldering it to the BGA footprint on the PC board or DIMM card where the DRAM normally would be soldered. Then you can solder the DDR3 DRAM to the top side of the BGA probe adapter. These attachment steps may occur in any order.

The probe is designed to tolerate lead‑free soldering temperature profiles. However, we recommend you apply the minimum temperature required for soldering and you use the minimum number of heating and cooling cycles to reduce risk of any damage to the probe. The probe is supplied without solder balls attached. Depending on the exact attachment order, you may prefer to use either leaded or lead-free solder to attach the BGA probe adapter.

We recommend you attach the BGA probe during the manufacturing process. For designs that are manufactured, it will require expertise to attach the BGA probe adapter. If you lack the in-house expertise to attach the BGA probe adapter, you may wish to work with a contract manufacturer with this expertise that may be willing to perform the attachment for a fee. You can find more information on BGA soldering and rework techniques that may be useful in attaching the probe at:

http://www.circuitrework.com/guides/9-0.shtm

http://www.keysight.com/find/ddr3bga-scope