HYB18M1G16 Datasheet, PDF (41/65 Pages) Qimonda AG – 1-Gbit x16 DDR Mobile-RAM

Data Sheet
2.4.8
PRECHARGE
The PRECHARGE command is used to deactivate (close) the
open row in a particular bank or the open rows in all banks.
The bank(s) will be available for a subsequent row access a
specified time (t_RP) after the PRECHARGE command is
issued. Input A10 determines whether one or all banks are to
be precharged, and in the case where only one bank is to be
precharged, inputs BA0, BA1 select the bank. Otherwise
BA0, BA1 are treated as “Don’t Care.”
Once a bank has been precharged, it is in the idle state and
must be activated prior to any READ or WRITE commands
being issued to that bank. A PRECHARGE command will be
treated as a NOP if there is no open row in that bank, or if the
previously open row is already in the process of precharging.
HY[B/E]18M1G16[0/1]BF
1-Gbit DDR Mobile-RAM
FIGURE 32
PRECHARGE Command
CK
CK
CKE
CS
RAS
CAS
WE
A0-A9
A11,A12
A10
BA0,BA1
(High)
All Banks
One Bank
BA
= Don't Care
BA = Bank Address
(if A10 = L, otherwise Don't Care)
Parameter
TABLE 13
Timing Parameters for PRECHARGE Command
Symbol
-6
- 7.5
Unit Note
min. max. min. max.
ACTIVE to PRECHARGE command period
t_RAS
42
70,000 45
70,000 ns
1)
PRECHARGE command period
t_RP
18 –
22.5 –
ns
1)
WRITE recovery time
t_WR
15 –
15 –
ns
1)
1) These parameters account for the number of clock cycles and depend on the operating frequency, as follows:
no. of clock cycles = specified delay / clock period; round to the next higher integer.
Rev.1.0, 2007-03
41
10242006-Y557-TZXW