168 pin DRAM DIMM (Unbuffered) Pinout

Personal Computer Memory Module description, 168-pin DIMM Pin out.
The 168-pin DIMM have 84 pins per PWB side.
The Front Side board pinout contains left side pins 1-42, and right side pins 43-84.
The Back Side board pinout has left side pins 85-126, and right side pins 127-168.
168-pin DIMM memory modules would be found in Desktop computers.

Front, Left Side Signals

In order to keep this page at a reasonable size,
refer here for the pin out of Front side 168-pin DIMM pin out.
The pin out below related to the back or rear-side of a 168-pin DIMM.

Back, Left Side Signals

168-Pin SDRAM DIMM PinOut
Pin # Non-Parity Parity 72 ECC 80 ECC Pin Description
85 Vcc Ground
86 DQ32 Data 32
87 DQ33 Data 33
88 DQ34 Data 34
89 DQ35 Data 35
90 Vcc +5 VDC or +3.3 VDC
91 DQ36 Data 36
92 DQ37 Data 37
93 DQ38 Data 38
94 DQ39 Data 39
95 DQ40 Data 40
96 Vss Ground
97 DQ41 Data 41
98 DQ42 Data 42
99 DQ43 Data 43
100 DQ44 Data 44
101 DQ45 Data 45
102 Vcc +5 VDC or +3.3 VDC
103 DQ46 Data 46
104 DQ47 Data 47
105 NC CB4 CB4 CB4 Parity/Check Bit Input/Output 4
106 NC CB5 CB5 CB5 Parity/Check Bit Input/Output 5
107 Vss Ground
108 NC NC NC CB12 Parity/Check Bit Input/Output 12
109 NC NC NC CB13 Parity/Check Bit Input/Output 13
110 Vcc +5 VDC or +3.3 VDC
111 NC No Connection
112 /CAS4 Column Address Strobe 4
113 /CAS5 Column Address Strobe 5
114 /RAS1 Row Address Strobe 1
115 NC No Connection
116 Vss Ground
117 A1 Address 1
118 A3 Address 3
119 A5 Address 5
120 A7 Address 7
121 A9 Address 9
122 A11 Address 11
123 A13 Address 13
124 Vcc +5 VDC or +3.3 VDC
125 NC No Connection
126 NC No Connection

Back, Right Side Signals

168-Pin SDRAM DIMM PinOut
Pin # Non-Parity Parity 72 ECC 80 ECC Pin Description
127 VSS VSS VSS VSS Ground
128 NC NC NC NC No Connection
129 /RAS3 /RAS3 /RAS3 /RAS3 Column Address Strobe 3
130 /CAS6 /CAS6 /CAS6 /CAS6 Column Address Strobe 6
131 /CAS7 /CAS7 /CAS7 /CAS7 Column Address Strobe 7
132 NC NC NC NC No Connection
133 VCC VCC VCC VCC +5 VDC or +3.3 VDC
134 NC NC NC CB14 Parity/Check Bit Input/Output 14
135 NC NC NC CB15 Parity/Check Bit Input/Output 15
136 NC CB6 CB6 CB6 Parity/Check Bit Input/Output 6
137 NC CB7 CB7 CB7 Parity/Check Bit Input/Output 7
138 VSS VSS VSS VSS Ground
139 DQ48 DQ48 DQ48 DQ48 Data 48
140 DQ49 DQ49 DQ49 DQ49 Data 49
141 DQ50 DQ50 DQ50 DQ50 Data 50
142 DQ51 DQ51 DQ51 DQ51 Data 51
143 VCC VCC VCC VCC +5 VDC or +3.3 VDC
144 DQ52 DQ52 DQ52 DQ52 Data 52
145 NC NC NC NC Not connected
146 NC NC NC NC No Connection
147 NC NC NC NC Not connected
148 VSS VSS VSS VSS Ground
149 DQ53 DQ53 DQ53 DQ53 Data 53
150 DQ54 DQ54 DQ54 DQ54 Data 54
151 DQ55 DQ55 DQ55 DQ55 Data 55
152 VSS VSS VSS VSS Ground
153 DQ56 DQ56 DQ56 DQ56 Data 56
154 DQ57 DQ57 DQ57 DQ57 Data 57
155 DQ58 DQ58 DQ58 DQ58 Data 58
156 DQ59 DQ59 DQ59 DQ59 Data 59
157 VCC VCC VCC VCC +5 VDC or +3.3 VDC
158 DQ60 DQ60 DQ60 DQ60 Data 60
159 DQ61 DQ61 DQ61 DQ61 Data 61
160 DQ62 DQ62 DQ62 DQ62 Data 62
161 DQ63 DQ63 DQ63 DQ63 Data 63
162 VSS VSS VSS VSS Ground
163 CK3 CK3 CK3 CK3  
164 NC NC NC NC Not connected
165 SA0 SA0 SA0 SA0 Serial Address 0
166 SA1 SA1 SA1 SA1 Serial Address 1
167 SA2 SA2 SA2 SA2 Serial Address 2
168 VCC VCC VCC VCC +5 VDC or +3.3 VDC

Data width is 64 bits per memory stick [the front side 84 pins are not connected together with the back side 84 pins]

168 Pin DIMM Memory Module
The approximate board size. 5.375" x 1.375"

SIMM: Single Inline Memory Module
DRAM: Dynamic Random Access Memory
SO DIMM: Small Outline Dual Inline Memory Module
SDRAM:: Synchronous DRAM (Random Access Memory), Synchronous to Positive Clock Edge.
FPM:Fast Page Mode: (asynchronous) Obsolete, faster than normal DRAM, used in 386/486 computers.
EDO: Extended Data Out: (asynchronous) A superset of FPM, just faster than FPM.
All 168 pin DIMMs use either 66MHz SDRAM, PC100 SDRAM, PC133 SDRAM, EDO or FPM memory. 168 pin DIMMs have two alignment notches as shown.
The left most notch [keyway] determines the DRAM type. If the notch is centered then the memory module is Buffered DRAM [EDO or Fast Page].
If the notch is off-set to the right then the memory module is either a un-buffered DRAM/SDRAM DIMM or a buffered SDRAM DIMM.
The center notch determines the voltage. If the notch is centered then the DIMM operates off 3.3 volts.

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or component manufacturers may be found by selecting the Components icon below.
Back to the main Computer Memory Modules information page. For electronic device manufacturers see one of these pages:
Memory IC manufacturers [individual IC's]
Memory Module manufacturers [memory sticks]
Memory Module Acronyms [Abbreviations used with memory sticks]
IC Memory Acronyms [abbreviations used with memory ICs]

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Modified 2/5/12
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