Ironwood Electronics has recently introduced a new high performance BGA socket for high speed probing of the memory chip and debugging of the system during the design phase. The SG-BGA-7182 socket is designed for 1 Gb Mobile DDR2-S4 SDRAM (12 x 12 mm, 0.5-mm pitch, 168 FBGA Package). The contact resistance is typically 20 milliohms per I/O. The socket connects all pins with 10 GHz bandwidth on all connections. The socket is mounted using supplied hardware on the target PCB with no soldering, and uses the smallest footprint in the industry. The footprint allows inductors, resistors, and decoupling capacitors to be placed very close to the device for impedance tuning. The socket also incorporates a new quick insertion method so that ICs can be changed out quickly. Customer can use this stacked socket to probe 1 Gb memory device using Agilent’s Flex Probe stacked inside the socket. Agilent’s probe makes contact with the target PCB through the 0.5-mm thick high density elastomer contact. Memory chip sits on top of the Probe and makes contact with it through a high speed elastomer contact as well. Agilent’s Probe brings out the signals to oscilloscope for high speed probing.
The SG-BGA-7182 sockets are constructed with high performance and low inductance embedded silver particle elastomer as the interconnect material between device and flex probe. The temperature range is -35°C to 100°C. The pin self inductance is 0.11 nH and mutual inductance of 0.025 nH. Capacitance to ground is 0.01 pF. Current capacity is 2.0 amps per pin. The second stack of interconnect uses gold plated embedded wire on elastomer between flex probe and target PCB and also accommodates the specification mentioned above.