CY7C1568V18-400BZXCT Cypress Semiconductor Corp, CY7C1568V18-400BZXCT Datasheet - Page 19

• Manufacturer Part Number: CY7C1568V18-400BZXCT
• Description: IC SRAM 72MBIT 400MHZ 165TFBGA
• Manufacturer: Cypress Semiconductor Corp

Specifications of CY7C1568V18-400BZXCT

• Format - Memory: RAM
• Memory Type: SRAM - Synchronous, DDR II
• Memory Size: 72M (2M x 36)
• Speed: 400MHz
• Interface: Parallel
• Voltage - Supply: 1.7 V ~ 1.9 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 165-TFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Power Up Sequence in DDR-II+ SRAM
DDR-II+ SRAMs must be powered up and initialized in a
predefined manner to prevent undefined operations. During
power up, when the DOFF is tied HIGH, the DLL is locked after
2048 cycles of stable clock.
Power Up Sequence
■
■
Power Up Waveforms
Document Number: 001-06551 Rev. *E
Apply power with DOFF tied HIGH (All other inputs can be
HIGH or LOW)
❐
❐
Provide stable power and clock (K, K) for 2048 cycles to lock
the DLL.
Apply V
Apply V
V DD /V DDQ
DOFF
DD
DDQ
before V
before V
K
K
DDQ
REF
or at the same time as V
Clock Start (Clock Starts after V DD /V DDQ is Stable)
Unstable Clock
V DD /V DDQ Stable (< + 0.1V DC per 50 ns)
Fix HIGH (tie to V DDQ )
Figure 3. Power Up Waveforms
REF
> 2048 Stable Clock
DLL Constraints
■
■
■
DLL uses K clock as its synchronizing input. The input must
have low phase jitter, which is specified as t
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 on to an incorrect frequency, causing unstable
SRAM behavior. To avoid this, provide 2048 cycles stable clock
to relock to the desired clock frequency.
CY7C1566V18, CY7C1577V18
CY7C1568V18, CY7C1570V18
Start Normal
Operation
KC Var
Page 19 of 28
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