深圳市锐鹏翔电子

a high speed synchronous dynamic random access memory SDRAM organized as words 4 banks 32 bitsThe default power up state of the mode register is unspecified. The following power up andinitialization sequence need to be followed to guarantee the device being preconditioned to each userspecific needs.During power up, all VDD and VDDQ pins must be ramp up simultaneously to the specified voltagewhen the input signals are held in the “NOP” state. The power up voltage must not exceed VDD +0.3Von any of the input pins or VDD supplies. After power up, an initial pause of 200 µS is requiredfollowed by a precharge of all banks using the precharge command. To prevent data contention on theDQ bus during power up, it is required that the DQM and CKE pins be held high during the initialpause period. Once all banks have been precharged, the Mode Register Set Command must beissued to initialize the Mode Register. An additional eight Auto Refresh cycles (CBR) are also requiredbefore or after programming the Mode Register to ensure proper subsequent operation