K5D5657ACM Datasheet, PDF (39/74 Pages) Samsung semiconductor – 256Mb NAND and 256Mb Mobile SDRAM

K5D5657ACM-F015
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MCP MEMORY
Partial Array Self Refresh
1. In order to save power consumption, Mobile SDRAM has PASR option.
2. Mobile SDRAM supports 3 kinds of PASR in self refresh mode : 4 Banks, 2 Banks and 1 Bank.
BA1=0 BA1=0
BA0=0 BA0=1
BA1=0 BA1=0
BA0=0 BA0=1
BA1=0 BA1=0
BA0=0 BA0=1
BA1=1 BA1=1
BA0=0 BA0=1
BA1=1 BA1=1
BA0=0 BA0=1
BA1=1 BA1=1
BA0=0 BA0=1
- 4 Banks
- 2 Banks
- 1 Bank
Partial Self Refresh Area
Internal Temperature Compensated Self Refresh (TCSR)
Note :
1. In order to save power consumption, Mobile DDR SDRAM includes the internal temperature sensor and control units to control the
self refresh cycle automatically according to the two temperature range ; Max. 40 °C, Max. 85 °C.
2. If the EMRS for external TCSR is issued by the controller, this EMRS code for TCSR is ignored.
Self Refresh Current (Icc 6)
Temperature Range
Unit
4 Banks
2 Banks
1 Bank
Max. 40 °C
200
160
130
uA
Max. 85 °C
480
300
220
B. POWER UP SEQUENCE
1. Apply power and attempt to maintain CKE at a high state and all other inputs may be undefined.
- Apply VDD before or at the same time as VDDQ.
2. Maintain stable power, stable clock and NOP input condition for a minimum of 200us.
3. Issue precharge commands for all banks of the devices.
4. Issue 2 or more auto-refresh commands.
5. Issue a mode register set command to initialize the mode register.
6. Issue a extended mode register set command to define DS or PASR operating type of the device after normal MRS.
EMRS cycle is not mandatory and the EMRS command needs to be issued only when DS or PASR is used.
The default state without EMRS command issued is half driver strength, all 4 banks refreshed.
The device is now ready for the operation selected by EMRS.
For operating with DS or PASR , set DS or PASR mode in EMRS setting stage.
In order to adjust another mode in the state of DS or PASR mode, additional EMRS set is required but power up sequence is not
needed again at this time. In that case, all banks have to be in idle state prior to adjusting EMRS set.
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Revision 0.1
September 2003