CY62157DV20

The CY62157DV20 is a high-performance CMOS static RAM organized as 512K words by 16 bits. This device features advanced circuit design to provide ultra-low active current. This is ideal for providing More Battery Life™ (MoBL™) in portable applications such as cellular telephones. The CY62157DV20 also has an automatic power-down feature that significantly reduces power consumption by 99% when addresses are not toggling. The CY62157DV20 can also be put into standby mode when deselected Chip Enable 1 (CE₁) HIGH or Chip Enable 2 (CE₂) LOW or both BHE and BLE are HIGH. The input/output pins (I/O₀ through I/O₁₅) are placed in a high-impedance state when: deselected Chip Enable 1 (CE₁) HIGH or Chip Enable 2 (CE₂) LOW, outputs of CY62157DV20 are disabled (OE HIGH), both Byte High Enable and Byte Low Enable are disabled (BHE, BLE HIGH) or during a write operation (Chip Enable 1 (CE₁) LOW and Chip Enable 2 (CE₂) HIGH and WE LOW).

Writing to the CY62157DV20 is accomplished by taking Chip Enable 1 (CE₁) LOW and Chip Enable 2 (CE₂) HIGH and Write Enable (WE) input LOW. If Byte Low Enable (BLE) is LOW, then data from I/O pins (I/O₀ through I/O₇), is written into the location specified on the address pins (A₀ through A₁₈). If Byte High Enable (BHE) is LOW, then data from I/O pins of CY62157DV20 (I/O₈ through I/O₁₅) is written into the location specified on the address pins (A₀ through A₁₈).

Reading from the CY62157DV20 is accomplished by taking Chip Enable 1 (CE₁) LOW and Chip Enable 2 (CE₂) HIGH and Output Enable (OE) LOW while forcing the Write Enable (WE) HIGH. If Byte Low Enable (BLE) is LOW, then data from the memory location specified by the address pins of CY62157DV20 will appear on I/O0 to I/O7. If Byte High Enable (BHE) is LOW, then data from memory will appear on I/O₈ to I/O₁₅. See the truth table at the back of this data sheet for a complete description of read and write modes.