Browse Prior Art Database

Multiple Power Supply Memory Card

IP.com Disclosure Number: IPCOM000118878D
Original Publication Date: 1997-Aug-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Dell, T: AUTHOR [+3]

Abstract

Disclosed is a method of supporting DRAMs that can be used with multiple-power supply voltages on a single 168-pin DIMM.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 89% of the total text.

Multiple Power Supply Memory Card

      Disclosed is a method of supporting DRAMs that can be used with
multiple-power supply voltages on a single 168-pin DIMM.

      System components in computers work at different power
supply voltages.  Currently, 5.0V, 3.3V, and 2.5V power supplies are
common.  Card sockets, particularly 168-pin DIMMs (JEDEC Standard
MO-161), utilize a multiple notch scheme that prevents DIMMs built
with 3.3V parts, for example, from being plugged into a socket that
is powered  by a 5V supply.  This can prevent component damage.

      However, some devices are designed to work at multiple power
supply voltages in a totally transparent manner.  The savings
provided by having only one device part number is substantially
negated if there  are still two DIMM part numbers required, the only
difference being the  position of the voltage notch.

      By taking advantage of the fact that the notching scheme has
adjacent but distinct notches for successive generations of power
supplies, a DIMM can be fabricated such that it can be used in
multiple power supply systems (assuming the device on the DIMM is a
multiple power  supply device) by simply enlarging the notch to
encompass two or more of  the JEDEC Standard distinct notch positions
as shown in the accompanying  diagrams.

      This method can also be extended to other types of notches or
keying structures, such as the JEDEC Standard 168-pin DIMM function
notch, where multip...