
 PRELIMINARY
CY7C1416BV18
CY7C1427BV18
CY7C1418BV18
CY7C1420BV18
Document Number: 001-07033  Rev. *B
Page 6 of 28
Pin Definitions 
Pin Name
I/O
Pin Description
DQ
[x:0]
Input/Output-
Synchronous
Data Input/Output signals
. Inputs are sampled on the rising edge of K and K clocks during valid 
Write operations. These pins drive out the requested data during a Read operation. Valid data is 
driven out on the rising edge of both the C and C clocks during Read operations or K and K when 
in single clock mode. When read access is deselected, Q
[x:0]
 are automatically tri-stated.
CY7C1416BV18 
 DQ
[7:0]
CY7C1427BV18 
 DQ
[8:0]
CY7C1418BV18 
 DQ
[17:0]
CY7C1420BV18 
 DQ
[35:0]
Synchronous Load
. This input is brought LOW when a bus cycle sequence is to be defined. 
This definition includes address and Read/Write direction. All transactions operate on a burst of 
2 data. LD must meet the set-up and hold times around edge of K.
Nibble Write Select 0, 1 
 active LOW
(CY7C1416BV18 only)
. Sampled on the rising edge of 
the K and K clocks during Write operations. Used to select which nibble is written into the device 
during the current portion of the Write operations. Nibbles not written remain unaltered.
NWS
0
 controls D
[3:0] 
and NWS
1
 controls D
[7:4]
.
All the Nibble Write Selects are sampled on the same edge as the data. Deselecting a Nibble 
Write Select will cause the corresponding nibble of data to be ignored and not written into the 
device.
Byte Write Select 0, 1, 2, and 3 - active LOW
. Sampled on the rising edge of the K and K clocks 
during Write operations. Used to select which byte is written into the device during the current 
portion of the Write operations. Bytes not written remain unaltered.
CY7C1427BV18 
 BWS
0
 controls D
[8:0] 
CY7C1418BV18
 
 BWS
0
 controls D
[8:0]
 and BWS
1
 controls D
[17:9].
CY7C1420BV18
 
 BWS
0
 controls D
[8:0]
, BWS
1
 controls D
[17:9]
, BWS
2
 controls D
[26:18]
 and BWS
3
controls D
[35:27]
.
All the Byte Write Selects are sampled on the same edge as the data. Deselecting a Byte Write 
Select will cause the corresponding byte of data to be ignored and not written into the device.
Address Inputs
. These address inputs are multiplexed for both Read and Write operations. 
Internally, the device is organized as 4M x 8 (2 arrays each of 2M x 8) for CY7C1416BV18 and 
4M x 9 (2 arrays each of 2M x 9) for CY7C1420BV18, a single 2M x 18 array for CY7C1427BV18, 
and a single array of 1M x 36 for CY7C1418BV18.
CY7C1416BV18 – Since the least significant bit of the address internally is a “0,” only 21 external 
address inputs are needed to access the entire memory array. 
CY7C1420BV18 – Since the least significant bit of the address internally is a “0,” only 21 external 
address inputs are needed to access the entire memory array. 
CY7C1427BV18 – A0 is the input to the burst counter. These are incremented in a linear fashion 
internally. 21 address inputs are needed to access the entire memory array.
CY7C1418BV18 – A0 is the input to the burst counter. These are incremented in a linear fashion 
internally. 20 address inputs are needed to access the entire memory array. All the address inputs 
are ignored when the appropriate port is deselected. 
Synchronous Read/Write Input
. When LD is LOW, this input designates the access type (Read 
when R/W is HIGH, Write when R/W is LOW) for loaded address. R/W must meet the set-up and 
hold times around edge of K.
Positive Input Clock for Output Data
. C is used in conjunction with C to clock out the Read data 
from the device. C and C can be used together to deskew the flight times of various devices on 
the board back to the controller. See application example for further details.
Negative Input Clock for Output Data
. C is used in conjunction with C to clock out the Read 
data from the device. C and C can be used together to deskew the flight times of various devices 
on the board back to the controller. See application example for further details.
Positive Input Clock Input
. The rising edge of K is used to capture synchronous inputs to the 
device and to drive out data through Q
[x:0] 
when in single clock mode. All accesses are initiated 
on the rising edge of K. 
LD
Input-
Synchronous
NWS
0
, NWS
1
Input-
Synchronous
BWS
0
, BWS
1
, 
BWS
2
, BWS
3
Input-
Synchronous
A, A0
Input-
Synchronous
R/W
Input-
Synchronous
C
Input-
Clock
C
Input-
Clock
K
Input-
Clock
K
Input-
Clock
Negative Input Clock Input
. K is used to capture synchronous data being presented to the device 
and to drive out data through Q
[x:0]
 when in single clock mode.
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