Tips from Tektronix for Probing Memory

Testing DDR DIMM signals is challenging. In particular, connecting probes to DIMM modules is one of the main difficulties for testing DDR, DDR2, and DDR3 DIMMs. Signals on the DDR DIMM module may be hard to access, especially when two or more DIMM modules are inserted adjacent to each other or in close confines with other components on a motherboard. With 20 or more test points on a board that need to be tested, probes need to be easily and reliably moved from point to point without having to turn off the device under test (DUT). The preferred method for probing is a solder tip or soldered wire. With so many test points on a DIMM and each needing its own tip, cost can quickly become an issue. Vendors may need to test dozens, if not hundreds of DIMM modules a year, so the tips need to either be inexpensive or easily reusable. The several new Tektronix probe tips for the P7500 series provide a high bandwidth, easy-to-use, and cost effective solution for testing DDR DIMMs.

The new Micro-Coax Tip consists of a square pin connector and a small circuit board with axial-leaded resistors separated by over an inch of micro-coax cables. The axial-leaded resistors are ideal for soldering to small circuit board features. The micro-coax is long enough that connections to the socket cable can occur at the top of a DIMM and also act as strain relief for the solder joints.

The High Temperature Tip and probing accessory for the P7500 extends the operating range to -55o C to 150 o C. The high temperature probing accessory consists of a Socket Cable XL and a High Temperature Tip. This is ideal for probing circuit boards tested inside of environmental chambers or probing circuit boards inside of blade servers where the distance between the oscilloscope and the circuit to be probed can be up to 2.5 meters apart. The High Temperature Tip consists of a small circuit board. On one end is a square pin header to mate with Socket Cable XL. The other end of the tip has axial-leaded resistors for the customer to solder to the DUT.

The new Damped Wire Tip provides an extremely simplified differential connection, consisting of a resistor wire for connection to the DUT and a square pin for insertion into a Square Pin Socket Cable. This allows signal and ground connections to be completely independent of each other. The user can independently match a single ground wire to the signal wire of choice, useful in many environments such as DDR and DRAM that have a high number of single-ended connections.