K4D553238F Datasheet, PDF (15/17 Pages) Samsung semiconductor – 256Mbit GDDR SDRAM

K4D553238F-GC
256M GDDR SDRAM
AC CHARACTERISTICS (I)
Parameter
Row cycle time
Refresh row cycle time
Row active time
RAS to CAS delay for Read
RAS to CAS delay for Write
Row precharge time
Row active to Row active
Last data in to Row precharge
Symbol
tRC
tRFC
tRAS
tRCDRD
tRCDWR
tRP
tRRD
tWR
-2A
Min
Max
42.9
-
48.6
-
28.6
100K
13.2
-
6.6
-
13.2
-
9.9
-
14.3
-
-33
Min
42.9
49.5
29.7
13.2
6.6
13.2
9.9
16.5
Max
-
-
100K
-
-
-
-
-
-36
Min
46.8
54
32.4
14.4
7.2
14.4
10.8
18
Max
-
-
100K
-
-
-
-
-
Last data in to Row precharge
@Auto Precharge
tWR_A
5
-
5
-
5
-
Auto precharge write recovery +
Precharge
tDAL
10
-
9
-
9
-
Last data in to Read command
tCDLR
2
-
2
-
2
-
Col. address to Col. address
tCCD
1
-
1
-
1
-
Mode register set cycle time
tMRD
2
-
2
-
2
-
Exit self refresh to read command tXSR
200
-
200
-
200
-
Power down exit time
tPDEX
3tCK+
tIS
-
3tCK+
tIS
-
3tCK+
tIS
-
Refresh interval time
tREF
7.8
-
7.8
-
7.8
-
Note : 1. For normal write operation, even numbers of Din are to be written inside DRAM
2. The number of clock of tRP is restricted by the number of clock of tRAS and tRP
3. The number of clock of tWR_A is fixed. It can’t be changed by tCK
4. tRCDWR is equal to tRCDRD-2tCK and the number of clock can not be lower than 2tCK.
5. The minimum number of clock cycles is determined by dividing the minimum time required with clock cycle time and then
rounding off to the next higher integer unconditionally.
Unit Note
ns 2,5
ns
5
ns
5
ns
5
ns
4
ns
5
ns
5
ns
5
tCK 3
tCK 3,5
tCK 1
tCK
tCK
tCK
ns
us
AC CHARACTERISTICS (II)
K4D553238F-GC2A
Frequency
Cas Latency tRC
350MHz ( 2.86ns )
4
15
300MHz ( 3.3ns )
4
13
275MHz ( 3.6ns )
4
13
tRFC
17
15
15
tRAS tRCDRD tRCDWR tRP
10
5
3
5
9
4
2
4
9
4
2
4
tRRD
4
3
3
tDAL Unit
10
tCK
9
tCK
9
tCK
K4D553238F-GC33
Frequency
Cas Latency tRC
300MHz ( 3.3ns )
4
13
275MHz ( 3.6ns )
4
13
tRFC
15
15
tRAS tRCDRD tRCDWR tRP
9
4
2
4
9
4
2
4
tRRD
3
3
tDAL Unit
9
tCK
9
tCK
K4D553238F-GC36
Frequency
Cas Latency tRC
275MHz ( 3.6ns )
4
13
tRFC
15
tRAS tRCDRD tRCDWR tRP
9
4
2
4
tRRD
3
tDAL Unit
9
tCK
- 15 -
Rev 1.3 (Mar. 2005)