K4S51153PF - Y(P)F

September 2004

11

Mobile SDRAM

1. In order to save power consumption, Mobile SDRAM has PASR option.

2. Mobile SDRAM supports 3 kinds of PASR in self refresh mode : Full Array, 1/2 of Full Array and 1/4 of Full Array.

BA1=0

Partial Self Refresh Area

BA0=0

BA1=0

BA0=0

BA1=0

BA0=1

BA1=1

BA0=1

BA1=1

BA0=0

BA1=1

BA0=1

BA1=1

BA0=0

BA1=0

BA0=1

BA1=0

BA0=0

BA1=0

BA0=1

BA1=1

BA0=1

BA1=1

BA0=0

Partial Array Self Refresh

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 the half driver strength and full array 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.

- Full Array

- 1/2 Array

- 1/4 Array

Note :

1. In order to save power consumption, Mobile-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. 70 °C.

2. If the EMRS for external TCSR is issued by the controller, this EMRS code for TCSR is ignored.

Temperature Range

Self Refresh Current (Icc 6)

Unit

Full Array

1/2 of Full Array

1/4 of Full Array

Max. 40

°C

400

320

280

uA

Max. 70

°C

900

600

500

Internal Temperature Compensated Self Refresh (TCSR)