PRELIMINARY
CY7C1510V18
CY7C1525V18
CY7C1512V18
CY7C1514V18
Document #: 38-05489 Rev. *A
Page 7 of 24
Functional Overview
The CY7C1510V18,CY7C1525V18,CY7C1512V18 and
CY7C1514V18 are synchronous pipelined Burst SRAMs
equipped with both a Read port and a Write port. The Read
port is dedicated to Read operations and the Write port is
dedicated to Write operations. Data flows into the SRAM
through the Write port and out through the Read Port. These
devices multiplex the address inputs in order to minimize the
number of address pins required. By having separate Read
and Write ports, the QDR-II completely eliminates the need to
“turn-around” the data bus and avoids any possible data
contention, thereby simplifying system design. Each access
consists of two 8-bit data transfers in the case of
CY7C1510V18, two 9-bit data transfers in the case of
CY7C1525V18,two 18-bit data transfers in the case of
CY7C1512V18 and two 36-bit data transfers in the case of
CY7C1514V18, in one clock cycle.
Accesses for both ports are initiated on the rising edge of the
positive Input Clock (K). All synchronous input timings are
referenced from the rising edge of the input clocks (K and K)
and all output timings are referenced to the rising edge of
output clocks (C and C or K and K when in single clock mode).
All synchronous data inputs (D[x:0]) inputs pass through input
registers controlled by the input clocks (K and K). All
synchronous data outputs (Q[x:0]) outputs pass through output
registers controlled by the rising edge of the output clocks (C
and C or K and K when in single clock mode).
All synchronous control (RPS, WPS, BWS[x:0]) inputs pass
through input registers controlled by the rising edge of the
input clocks (K and K).
CY7C1512V18 is described in the following sections. The
same
basic
descriptions
apply
to
CY7C1510V18
CY7C1525V18 and CY7C1514V18.
Read Operations
The CY7C1512V18 is organized internally as 2 arrays of
2Mx18. Accesses are completed in a burst of two sequential
18-bit data words. Read operations are initiated by asserting
RPS active at the rising edge of the Positive Input Clock (K).
The address is latched on the rising edge of the K Clock. The
address presented to Address inputs is stored in the Read
address register. Following the next K clock rise the corre-
sponding lowest order 18-bit word of data is driven onto the
Q[17:0] using C as the output timing reference. On the subse-
quent rising edge of C, the next 18-bit data word is driven onto
the Q[17:0]. The requested data will be valid 0.45 ns from the
K
Input-Clock
Negative Input Clock Input. K is used to capture synchronous inputs being presented
to the device and to drive out data through Q[x:0] when in single clock mode.
CQ
Echo Clock
CQ is referenced with respect to C. This is a free running clock and is synchronized
to the output clock (C) of the QDR-II. In the single clock mode, CQ is generated with
respect to K. The timings for the echo clocks are shown in the AC timing table.
CQ
Echo Clock
CQ is referenced with respect to C. This is a free running clock and is synchronized
to the output clock (C) of the QDR-II. In the single clock mode, CQ is generated with
respect to K. The timings for the echo clocks are shown in the AC timing table.
ZQ
Input
Output Impedance Matching Input. This input is used to tune the device outputs to the
system data bus impedance. CQ,CQ and Q[x:0] output impedance are set to 0.2 x RQ,
where RQ is a resistor connected between ZQ and ground. Alternately, this pin can be
connected directly to VDD, which enables the minimum impedance mode. This pin cannot
be connected directly to GND or left unconnected.
DOFF
Input
DLL Turn Off - Active LOW. Connecting this pin to ground will turn off the DLL inside
the device. The timings in the DLL turned off operation will be different from those listed
in this data sheet. More details on this operation can be found in the application note,
“DLL Operation in the QDR-II.”
TDO
Output
TDO for JTAG.
TCK
Input
TCK pin for JTAG.
TDI
Input
TDI pin for JTAG.
TMS
Input
TMS pin for JTAG.
NC
N/A
Not connected to the die. Can be tied to any voltage level.
VSS/144M
Input
Address expansion for 144M. This must be tied LOW on the 72M devices.
VSS/288M
Input
Address expansion for 288M. This must be tied LOW on the 72M devices.
VREF
Input-
Reference
Reference Voltage Input. Static input used to set the reference level for HSTL inputs
and Outputs as well as AC measurement points.
VDD
Power Supply
Power supply inputs to the core of the device.
VSS
Ground
Ground for the device.
VDDQ
Power Supply
Power supply inputs for the outputs of the device.
Pin Definitions (continued)
Pin Name
I/O
Pin Description