MT48V16M16LFFG Datasheet, PDF (9/58 Pages) Micron Technology – MOBILE SDRAM

ADVANCE
256Mb: x16
MOBILE SDRAM
EXTENDED MODE REGISTER
BA1 BA0 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 Address Bus
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 0 All have to be set to "0" DS TCSR PASR
Extended Mode
Register (Ex)
A5 Driver Strength
0 ^{Half Strength}
1 Full Strength
A4 A3 Maximum Case Temp
11
00
85˚C
70˚C
01
45˚C
10
15˚C
A2
A1
A0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Self Refresh Coverage
Four Banks
Two Banks (BA1=0)
One Bank (BA1=BA0=0)
RFU
RFU
Half Bank (BA1=BA0=0)
Quarter Bank (BA1=BA0=0)
RFU
NOTE: 1. E14 and E13 (BA1 and BA0) must be “1, 0” to select the
Extended Mode Register (vs. the base Mode Register).
EXTENDED MODE REGISTER
The Extended Mode Register controls the functions
beyond those controlled by the Mode Register. These
additional functions are special features of the
BATRAM device. They include Temperature Compen-
sated Self Refresh (TCSR) Control, and Partial Array
Self Refresh (PASR).
The Extended Mode Register is programmed via
the Mode Register Set command (BA1=1,BA0=0) and
retains the stored information until it is programmed
again or the device loses power.
The Extended Mode Register must be programmed
with M6 through M12 set to “0”. The Extended Mode
Register must be loaded when all banks are idle and no
bursts are in progress, and the controller must wait the
specified time before before initiating any subsequent
operation. Violating either of these requirements re-
sults in unspecified operation.
TEMPERATURE COMPENSATED SELF REFRESH
Temperature Compensated Self Refresh allows the
controller to program the Refresh interval during SELF
REFRESH mode, according to the case temperature of
the BATRAM device. This allows great power savings
during SELF REFRESH during most operating tempera-
ture ranges. Only during extreme temperatures would
the controller have to select a TCSR level that will guar-
antee data during SELF REFRESH.
Every cell in the DRAM requires refreshing due to
the capacitor losing its charge over time. The refresh
rate is dependent on temperature. At higher tempera-
tures a capacitor loses charge quicker than at lower
temperatures, requiring the cells to be refreshed more
often. Historically, during Self Refresh, the refresh rate
has been set to accomodate the worst case, or highest
temperature range expected.
256Mb: x16 Mobile SDRAM
MobileRamY26L_A.p65 – Pub. 5/02
9
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2002, Micron Technology, Inc.