W641GG2JB Datasheet, PDF (52/109 Pages) Winbond – 1-Gbit GDDR3 Graphics SDRAM

W641GG2JB
1-Gbit GDDR3 Graphics SDRAM
6.8.2.1 Extended Mode Register 2 (EMRS2)
BA2 BA1 BA0 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
0
1
0
OCD Pulldown
Offset
ODT Pullup
Offset
Merged
Mode
Reserved
A11 A10
A9
OCD PD
Offset
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
111
0 (*)
+1
+2
+3
RFU
-3
-2
-1
A8
A7
A6
ODT PU
Offset
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
0 (*)
+1
+2
+3
RFU
-3
-2
-1
A5 Merged Mode
0 Non-Merged (*)
1
Merged
(*) = Default value at power-up
6.8.2.2 Impedance Offsets
The driver and termination impedances may be offset individually for output driver and data termination. The offset impedance step
values correspond to a nominal value of TBD. With negative offset steps the drive strengths will be decreased and Ron will be
increased. With positive offset steps the drive strengths will be increased and Ron will be decreased.
6.8.2.3 Merged Mode
Merged Mode combines the specific pins of 1-CS Mode (A12) and 2-CS Mode (CS1#) on a single physical pin (J-3).
6.8.3 OCD Pull Down Offset
The 1G GDDR3 add the ability to add an offset to the Output impedance driver set using the bit A[1:0] of the EMRS. A range from
-3 to +3 can be chosen using A[11:9]. Each steps correspond to an approximate change of 1 Ohms. The offset will be applied also
on Autocal value if selected. The offset will be applied also on Autocal value if selected. With negative offset steps the Driver
Strength will be decreased and the Ron will be increased. With positive offset steps the Driver Strength will be increased and Ron
will be decreased.
6.8.4 ODT Pull Up Offset
The 1G GDDR3 add the ability to add an offset to the ODT set using the bit A[3:2] of the EMRS. A range from -3 to +3 can be
chosen using A[8:6]. Each steps correspond to an approximate change of 1.5 Ohms. With negative offset steps the Termination value
will be increased. With positive offset steps the Termination value will be decreased.
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Publication Release Date: Apr, 22, 2011
Revision A01-002