tjr@cbnewsc.att.com (thomas.j.roberts) (01/11/91)
I am designing a new board that uses 1 Meg by 9 DRAMS. Clearly, it is cheaper (and uses less board space) to use regularly-available SIMMs or SIPs than to use individual chips. These SIMMs and SIPs are used in scads of PC clones, PS/2s, Macs, etc.; they are often cheaper than 9 1Mx1 DRAM chips. Question: Which should I use, SIMMs or SIPs ?? The SIPs have through-hole pins, and no edge connector, so they appear to take less board-to-board space; SIMM sockets, however, are available to mount the SIMM at an angle, reducing their height (and board-to-board space). Connectors are readily available for both, and prices are comparable. What are the advantages/disadvantages of SIMMs and SIPs ?? Thanks in advance, Tom Roberts att!ihlpl!tjrob TJROB@IHLPL.ATT.COM
khoult@bbn.com (Kent Hoult) (01/11/91)
In article <1991Jan10.170127.9293@cbnewsc.att.com> tjr@cbnewsc.att.com (thomas.j.roberts) writes: >I am designing a new board that uses 1 Meg by 9 DRAMS. Clearly, >it is cheaper (and uses less board space) to use regularly-available >SIMMs or SIPs than to use individual chips. These SIMMs and SIPs >are used in scads of PC clones, PS/2s, Macs, etc.; they are often >cheaper than 9 1Mx1 DRAM chips. > >Question: Which should I use, SIMMs or SIPs ?? > >What are the advantages/disadvantages of SIMMs and SIPs ?? SIPs - they are slightly less common than SIMMs - they are soldered in, so adding/removing modules is harder + they only mount vertically, this lets you mount them as close as 0.3" apart (maybe 0.25"). - They only mount vertically, needing more height. SIMMs - They need a socket, this costs money. + They need a socket, this makes them easy to add/remove. + The sockets are available in vertical, angled, and horizontal mounts. - The angled mount sockets can't be spaced closer than 0.5" apart, so more board space is used by them. + They are slightly more common and are easier to produce than a SIP, so they should be a bit cheaper. These are the main points I could remember of off the top of head. I've designed boards using both, and these were the main factors. ------------------------------------------------------------------------------- Kent Hoult, BBN Communications Corp., Cambridge, MA khoult@bbn.com TEL: (617) 873-4385 -------------------------------------------------------------------------------