CY7C1241V18, CY7C1256V18
CY7C1243V18, CY7C1245V18
Document Number: 001-06365 Rev. *D
Page 7 of 28
CQ
Echo Clock
Synchronous Echo Clock Outputs
. This is a free running clock and is synchronized to the
input clock (K) of the QDR-II+. The timing for the echo clocks is shown in
“Switching Character-
istics” on page 23
.
CQ
Echo Clock
Synchronous Echo Clock Outputs
. This is a free running clock and is synchronized to the
input clock (K) of the QDR-II+. The timing for the echo clocks is shown in
“Switching Character-
istics” on page 23
.
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. Alternatively, this pin can be connected directly to
V
DDQ
, 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 turns off the DLL inside the device.
The timing in the DLL turned off operation is different from that listed in this data sheet. For
normal operation, this pin can be connected to a pull up through a 10 Kohm or less pull up
resistor. The device behaves in QDR-I mode when the DLL is turned off. In this mode, the device
can be operated at a frequency of up to 167 MHz with QDR-I timing.
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.
NC/72M
N/A
Not Connected to the Die
. Can be tied to any voltage level.
NC/144M
N/A
Not Connected to the Die
. Can be tied to any voltage level.
NC/288M
N/A
Not Connected to the Die
. Can be tied to any voltage level.
V
REF
Input-
Reference
Reference Voltage Input
. Static input used to set the reference level for HSTL inputs, outputs,
and AC measurement points.
V
DD
Power Supply
Power Supply Inputs to the Core of the Device
.
V
SS
Ground
Ground for the Device
.
V
DDQ
Power Supply
Power Supply Inputs for the Outputs of the Device
.
Pin Definitions
(continued)
Pin Name
IO
Pin Description
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