I am using an ARM M based development board (1) from TI. I wish to extend RAM (from default 256KB to 256 KB+ 8MB)by following the provided reference design (2).
The design uses an ISSI DRAM IS42S16320D (3) that comes in a Surface mount TSOP-54 package. Gerber files are provided in the reference design. Instead of getting a PCB manufactured, can I make use of any TSOP-54 to X adapter such that the IC goes onto a perf board and in turn connect this protoype perf board to my TI development board ?
I've come across TSOP-54 (II) to DIP-54 SMT Adapter but don't quite understand how it works.
If it worth the effort to use adapters to eventually use a TSOP-54 package IC on a perf board and will there be any problems with operation ?
Could any one suggest if this is a good way to proceed or just get a pcb manufactured ?
(1): http://www.ti.com/tool/dk-tm4c129x
(2): http://www.ti.com/tool/tidm-tm4c129xsdram
(3): http://www.mouser.in/ProductDetail/ISSI/IS42S16320D-7TL/?qs=Fza4peKjXe%2FI0m31MwCZFQ%3D%3D
Best Answer
The most common penalty for using SMT to DIP adaptors is ground-bounce noise, so you will NOT be able to run a DIP package as fast as using a proper TSOP-54 pattern. If the DRAM is clocked less than 25 to 50 MHZ it should work ok.
Ground-bounce affects the voltage at the outputs of the DRAM causing noise on data transitions, resulting in possible corrupted reads from the DRAM. Install many bypass capacitors of 100nF at all the power connections to the DRAM.
Keep ground connections as short as possible, as long connections create the ground-bounce, which is a reflection of sharp transitions in the output based on the fast transitions in current which have to be returned to the DRAM's ground connections. Long connections act to reflect this current back into the DRAM IC, like RF signal reflected back from an antenna not matched to the frequency it is working with.
You can also insert 22 ohm 1/10 watt smd resistors in the data lines to suppress the sharp rising and falling edges of the data, This will cut down some on ground-bounce. Not guaranteed to work at 60MHZ, but it will help.
In the long run consider a custom PCB with a TSOP-54 pattern for the DRAM.