Apple Desktop Computer manual RAM SO-DIMM Electrical Limits, Address Multiplexing

C H A P T E R 4

RAM Expansion

Address Multiplexing

Signals A[0] – A[13] on each RAM SO-DIMM make up a 14-bit multiplexed address bus that can support several different types of SDRAM devices. Table 4-2 lists the types of devices that can be used in the iMac computer by size, configuration, and sizes of row and column addresses.

IMPORTANT

The iMac supports only the types of SDRAM devices specified in Table 4-2. Other types of DRAM devices should not be used with this computer. ▲

Table 4-2	Types of DRAM devices
		Size of	Size of
	Device	row	column
Device size	configuration	address	address
16 Mbits	2M x 4 x 2	11	10
16 Mbits	1M x 8 x 2	11	9
16 Mbits	512K x 16 x 2	11	8
64 Mbits	8M x 4 x 2	13	10
64 Mbits	4M x 4 x 4	12	10
64 Mbits	4M x 8 x 2	13	9
64 Mbits	2M x 8 x 4	12	9
64 Mbits	2M x 16 x 2	13	8
64 Mbits	1M x 16 x 4	12	8
64 Mbits	1M x 32 x 2	13	7
64 Mbits	512K x 32 x 4	12	7

RAM SO-DIMM Electrical Limits

Each RAM SO-DIMM must not exceed the following maximum current limits on the +3 V supply:

52Main RAM Expansion