CY7C4255-25AC Cypress Semiconductor Corp, CY7C4255-25AC Datasheet - Page 18

• Manufacturer Part Number: CY7C4255-25AC
• Manufacturer: Cypress Semiconductor Corp

Specifications of CY7C4255-25AC

• Density: 128Kb
• Word Size: 18b
• Sync/async: Synchronous
• Expandable: Yes
• Package Type: TQFP
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 64
• Lead Free Status / Rohs Status: Not Compliant

Document #: 38-06004 Rev. *C
Depth Expansion Configuration
(with Programmable Flags)
The CY7C4255/65 can easily be adapted to applications
requiring more than 8192/16384 words of buffering. Figure 2
shows Depth Expansion using three CY7C42X5s. Maximum
depth is limited only by signal loading. Follow these steps:
1. The first device must be designated by grounding the First
2. All other devices must have FL in the HIGH state.
DATA IN(D)
Load (FL) control input.
LOAD (LD)
FF
PAF
Figure 2. Block Diagram of 8Kx18/16Kx18 Synchronous FIFO Memory
WRITE CLOCK(WCLK)
WRITE ENABLE(WEN)
RESET (RS)
with Programmable Flags used in Depth Expansion Configuration
FIRST LOAD (FL)
V
V
CC
CC
FF
PAF
FF
PAF
FF
PAF
FL
FL
WXO RXO
WXO RXO
WXO RXO
7C4255
7C4265
WXI RXI
7C4255
7C4265
WXI RXI
7C4255
7C4265
WXI RXI
3. The Write Expansion Out (WXO) pin of each device must
4. The Read Expansion Out (RXO) pin of each device must
5. All Load (LD) pins are tied together.
6. The Half-Full Flag (HF) is not available in the Depth
7. EF, FF, PAE, and PAF are created with composite flags by
PAE
PAE
PAE
EF
EF
EF
be tied to the Write Expansion In (WXI) pin of the next
device.
be tied to the Read Expansion In (RXI) pin of the next
device.
Expansion Configuration.
ORing together these respective flags for monitoring. The
composite PAE and PAF flags are not precise.
READ CLOCK(RCLK)
READ ENABLE(REN)
OUTPUT ENABLE(OE)
PAE
EF
DATA OUT (Q)
CY7C4255
CY7C4265
Page 18 of 22
[+] Feedback