Cypress CY7C1321CV18, CY7C1319CV18, CY7C1317CV18 Power Up Sequence in DDR-II Sram, DLL Constraints

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CY7C1317CV18, CY7C1917CV18 CY7C1319CV18, CY7C1321CV18

Power Up Sequence in DDR-II SRAM

DDR-II SRAMs must be powered up and initialized in a predefined manner to prevent undefined operations.

Power Up Sequence

■Apply power and drive DOFF either HIGH or LOW (all other inputs can be HIGH or LOW).

❐Apply VDD before VDDQ.

❐Apply VDDQ before VREF or at the same time as VREF.

❐Drive DOFF HIGH.

DLL Constraints

■DLL uses K clock as its synchronizing input. The input must have low phase jitter, which is specified as tKC Var.

■The DLL functions at frequencies down to 120 MHz.

■If the input clock is unstable and the DLL is enabled, then the DLL may lock onto an incorrect frequency, causing unstable SRAM behavior. To avoid this, provide1024 cycles stable clock to relock to the desired clock frequency.

■Provide stable DOFF (HIGH), power, and clock (K, K) for 1024 cycles to lock the DLL.

K

K

VDD/ VDDQ

DOFF

Figure 3. Power Up Waveforms

~ ~

	~ ~
Unstable Clock	> 1024 Stable clock	Start Normal
		Operation

Clock Start (Clock Starts after VDD/ V DDQ Stable)

VDD/ V DDQ Stable (< +/- 0.1V DC per 50ns )

Fix High (or tie to VDDQ)

Document Number: 001-07161 Rev. *D

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Contents Features ConfigurationsFunctional Description Selection GuideLogic Block Diagram CY7C1317CV18 Logic Block Diagram CY7C1917CV18Doff CLKBWS Logic Block Diagram CY7C1319CV18Logic Block Diagram CY7C1321CV18 Pin Configuration Ball Fbga 13 x 15 x 1.4 mm PinoutCY7C1317CV18 2M x CY7C1917CV18 2M xCY7C1319CV18 1M x CY7C1321CV18 512K xSynchronous Read/Write Input. When Pin DefinitionsPin Name Pin Description Power Supply Inputs to the Core of the Device Power Supply Inputs for the Outputs of the DeviceReferenced with Respect to TDO for JtagFunctional Overview Echo Clocks Depth ExpansionProgrammable Impedance Application Example SRAM#1 ZQSRAM#2 OperationWrite Cycle Descriptions CommentsWrite cycle description table for CY7C1321CV18 follows DeviceInto the device. D359 remains unaltered Device. D80 and D3518 remains unalteredIeee 1149.1 Serial Boundary Scan Jtag Idcode TAP Controller State Diagram State diagram for the TAP controller followsTAP Controller Block Diagram TAP Electrical Characteristics TAP AC Switching Characteristics TAP Timing and Test ConditionsIdentification Register Definitions Scan Register SizesInstruction Codes Register Name Bit SizeBoundary Scan Order Bit # Bump IDDLL Constraints Power Up Sequence in DDR-II SramPower Up Sequence Maximum Ratings Electrical CharacteristicsDC Electrical Characteristics Input LOW Voltage Vref Document Number 001-07161 Rev. *D AC Electrical CharacteristicsInput High Voltage Vref + Capacitance Thermal ResistanceParameter Description Test Conditions Max Unit Parameter Description Test Conditions Fbga UnitParameter Min Max Parameter Min Max Output Times DLL TimingSwitching Waveforms DON’T Care UndefinedOrdering Information 250 167 Package Diagram Ball Fbga 13 x 15 x 1.4 mmSales, Solutions, and Legal Information Worldwide Sales and Design Support Products PSoC Solutions