K4N26323AE Datasheet, PDF (29/52 Pages) Samsung semiconductor – 128Mbit GDDR2 SDRAM

K4N26323AE-GC
128M GDDR2 SDRAM
The On-die Termination for external two bank system with self-calibration code (A3, A2 = 0, 1)
The external resistor (Rref) is equal to 2X the number of shared DRAM’s on one channel X target termination value of DQ
channel. The following figure is represented the typical two bank system having on-die termination. 4 DRAM’s share one
channel for CMD and ADD pins and 2 DRAM’s share one channel for DQ’s and CLK pins. The external resistor (Rref) is 4
times of target termination value on channel. The On-die Termination value of CK, /CK, 32 DQ’s, 4 DM’s, 4 /DQS’s and
4DQS pins on channel is half value of the external resistor (Rref).
Block Diagram of 2 Banks System
CK, /CK
ADD
/RAS, /CAS, /WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
CK, /CK
DM’s, DQ’s,
DQS’s, /DQS’s
CK, /CK
/CS
/RAS, /CAS, /WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
CK, /CK
DM’s, DQ’s,
DQS’s, /DQS’s
Front Side DRAM’s
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
4 X Rterm
4 X Rterm
4 X Rterm
4 X Rterm
Back Side DRAM’s
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
Rref = 4 X Rterm
VSSQ
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
4 X Rterm
VSSQ
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
4 X Rterm
VSSQ
CK, /CK
ZQ
ADD
/RAS, /CAS,
/WE, /CS
DM’s, DQ’s,
DQS’s, /DQS’s
4 X Rterm
VSSQ
Self-refresh and power down mode in two bank system should be issued for all DRAM’s at the same time to keep suit-
able On-die termination condition on channel.
Mode
DRAM
.
Pin
Remarks
M1
M2
M1
M2
Self_refresh Self_refresh
All
OFF
OFF
*1
Self_refresh Other States
All
Illegal
CK,/CK
ON
ON
Power down Power down
Other pins
OFF
OFF
*1
Power down Other States
Illegal
CK, /CK, ADD’s, CMD
ON
ON
Active
DQ’s, DQS’s, /DQS’s, DM’s
ON
ON
CK, /CK, ADD’s, CMD
ON
All Banks idle
A10=1
DQ’s, DQS’s, /DQS’s, DM’s
ON
Read
CK, /CK, ADD’s, CMD
ON
A10=0
DQ’s, DQS’s, /DQS’s, DM’s
ON
ON
OFF
ON
ON
CK, /CK, ADD’s, CMD
ON
A10=1
DQ’s, DQS’s, /DQS’s, DM’s
ON
Active Read
CK, /CK, ADD’s, CMD
ON
A10=0
DQ’s, DQS’s, /DQS’s, DM’s
ON
ON
OFF
ON
ON
1. With these case, the system couldn’t have suitable Rterm.
Because the On-Die termination value on channel is two times than the target value.
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Rev. 1.7 (Jan. 2003)