F21 test board SIMM connector
- To: <MISC>
- Subject: F21 test board SIMM connector
- From: "John Griessen" <john_g@xxxxxxxxxx>
- Date: Tue, 23 Mar 1999 01:51:44 -0600
- Importance: Normal
Here's a possible for a DRAM connector. Are there DRAM's
available now in this form? They call it
Small Outline Single InLine Memory Module (SIMM),
but they also call it
Mini Memory Module (M3), Surface Mount (DIMM).
Surface mount makes the PC board simpler!
As I read the spec below, you have three simm module equivalents
located in a stack laying flat on your PC board if you lay out
one simm module directly on the PC board. Otherwise, you buy
and plug in a double sided simm in each connector. So for F21,
using 256K X 4 modules to get 20 bits requires 5 modules, 2 per connector =
3 connectors
See: http://connect.amp.com/107-8.html
New from AMP is the miniature M3 socket designed to accept the Small Outline
Single InLine Memory
Module (SIMM). The board space used by the M3 socket is only half that taken
by standard SIMM sockets.
In addition to saving space on the motherboard, the right angle design of
the socket stands only 5.5 mm
high, taking full advantage of the low profile Thin Small Outline Package
(TSOP). This allows one layer of
TSOPs to be mounted on the motherboard and a doublesided module (3.54 mm
nominal) with two layers
of TSOPs over the motherboard.
The socket is for surface mount applications and comes in a 72position
configuration. The mating face
contacts are on staggered dual row .050 [1.27] centers, while surface mount
tails are on single row .025
[0.64] centers.
A keying feature helps prevent module damage sometimes caused by
inadvertently inserting 3.5 V modules
into 5.0V systems.
Performance Characteristics
Termination Resistance
(Dry Circuit):
30 milliohms max: (initial)
Dielectric Withstanding
Voltage:
250 VAC
Insulation Resistance:
250 megohms min. (initial)
Operating Temperature:
55°C to +85°C
Durability:
25 cycles min.
Material and Finish
Housing Liquid Crystal Polymer (LCP), UL 94V0
Contacts Phosphor bronze with gold or tin plating in contact area and
tinlead plating on surface mount
tail