K4C561638C-TCD4000 Datasheet, PDF (14/42 Pages) Samsung semiconductor – 256Mb Network-DRAM

K4C5608/1638C
Power Up Sequence
256Mb Network-DRAM
1. As for PD, being maintained by the low state (<0.2V) is desirable before a power-supply injection.
2. Apply Vdd before or at the same time as VddQ.
3. Apply VddQ before or at the same time as V_REF.
4. Start clock (CK, CK) and maintain stable condition for 200us (min.).
5. After stable power and clock, apply DESL and take PD = H.
6. Issue EMRS to enable DLL and to define driver strength. (Note : 1)
7. Issue MRS for set CAS Latency (CL), Burst Type (BT), and Burst Length (BL). (Note : 1)
8. Issue two or more Auto-Refresh commands. (Note:1)
9. Ready for normal operation after 200 clocks from Extended Mode Register programming. (Note : 2)
Note : 1. Sequence 6, 7 and 8 can be issued in random order.
2. L=Logic Low, H = Logic High
V_DD
V_DDQ
V_REF
CLK
CLK
PD
Command
Address
DQ
DQS
2.5V(TYP)
2.5V(TYP)
1.25V(TYP)
200 µs(min)
t_PDEX
t_PDA
l_RSC
l_RSC
l_REFC
200 clock cycle(min)
l_REFC
DESL RDA MRS DESL RDA MRS DESL WRA REF DESL
op-code
op-code
WRA REF DESL
EMRS
MRS
Hi-Z
EMRS
MRS
Auto Refresh cycle
Nomal Operation
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REV. 0.7 Aug. 2003