JTAG External Modules (JEM_DIMM/SODIMM^TM) for the DDR2/DDR3 Memory Socket Test

The primary function of the JTAG External Modules (JEM) for the DIMM/SODIMM Socket Cluster Test is to provide test access to off-board signals that otherwise could not be accessed by a JTAG test system and to strengthen the memory-independent JTAG testing for the assembly correctness of the almost full spectrum of the modern socket types, particularly (according to JEDEC_Std.21-C): DIMM (Dual In-line Memory Module), miniDIMM, microDIMM, VLP DIMM sockets; SODIMM (Small Outline Dual In-line Memory Module) sockets; SORDIMM (Small Outline Registered Dual In-line Memory Module) sockets; SOCDIMM (Small Outline Clocked Dual In-line Memory Module) sockets; VLP SORDIMM (Very Low Profile Small Outline Registered Dual In-line Memory Module) sockets; FBDIMM (Fully Buffered Dual In-line Memory Module) sockets; CompactFlash Module sockets with form factor upon demand; etc.

For many designs, JTAG test has adequate access to on-board signals, but signals that go off the board often cannot be tested. By adding JTAG access to memory socket off-board signals, a JEM_DIMM/SODIMM^TM module can increase the board's fault coverage, possibly reducing the need for developing alternative tests to reach the required test coverage level. The JEM_DIMM/SODIMM module provides a number of JTAG accessible individually controlled test channels that can be used to control and observe signals that go off the board.

The JEM_DIMM/SODIMM^TM module provide full bi-directional JTAG controllability and observability for all socket pins and is fully compatible with the following JTAG ATPG platforms:

Flynn Systems onTAP Series 4000
Corelis ScanExpress
JTAG Technologies ProVision
Asset ScanWorks
Goepel' CASCON
XJTAG' XJRunner

The ATPG tools of each of these JTAG test platforms can generate tests with the advanced diagnostics for the socket pins failure detection, as well as sensing analog voltages on the individual power pins (such as Vdd, Vddq, Vddspd and Vref). The JEM_DIMM/SODIMM^TM module TAP channel can be simply combined with any board TAP chain or used as a separate TAP. An advantage over other similar solutions is that the JEM_DIMM/SODIMM^TM module connection setup can be done either with an external TAP cable or completely in-circuit, without any cabling! The modules design is ready for cascading multiple DDR2/DDR3 memory socket testing. Each JEM_DIMM/SODIMM^TM module features hot-swap capability.

Our JEM_DIMM/SODIMM^TM module product line consists of almost full spectrum of the modern socket types, more than 20 types right now, each additional DDR2/DDR3 memory socket type is also accessible upon request.

JEM with external TAP cable		JEM without external TAP cable (completely in-circuit)
SORDIMM Socket on PCB