CY7C4261, CY7C4271
16K/32K x 9 Deep Sync FIFOs
Features
Functional Description
■
High speed, low power, first-in first-out (FIFO) memories
■
16K × 9 (CY7C4261)
■
32K × 9 (CY7C4271)
■
0.5 micron CMOS for optimum speed and power
■
High speed 100 MHz operation (10 ns read/write cycle times)
■
Low power — ICC = 35 mA
The CY7C4261/71 are high speed, low power FIFO memories
with clocked read and write interfaces. All are nine bits wide. The
CY7C4261/71 are pin compatible to the CY7C42X1
Synchronous FIFO family. The CY7C4261/71 can be cascaded
to increase FIFO width. Programmable features include Almost
Full/Almost Empty flags. These FIFOs provide solutions for a
wide variety of data buffering needs, including high speed data
acquisition, multiprocessor interfaces, and communications
buffering.
■
Fully asynchronous and simultaneous read and write operation
■
Empty, Full, Half Full, and programmable Almost Empty and
Almost Full status flags
■
TTL compatible
■
Output Enable (OE) pins
■
Independent read and write enable pins
■
Center power and ground pins for reduced noise
■
Supports free running 50% duty cycle clock inputs
■
Width Expansion Capability
■
Military temp SMD Offering – CY7C4271-15LMB
■
32-pin PLCC/LCC and 32-pin TQFP
■
Pin compatible density upgrade to CY7C42X1 family
■
Pin compatible density upgrade to IDT72201/11/21/31/41/51
■
Pb-Free Packages Available
These FIFOs have 9-bit input and output ports that are controlled
by separate clock and enable signals. The input port is controlled
by a free-running clock (WCLK) and two write-enable pins
(WEN1, WEN2/LD).
When WEN1 is LOW and WEN2/LD is HIGH, data is written into
the FIFO on the rising edge of the WCLK signal. While WEN1,
WEN2/LD is held active, data is continually written into the FIFO
on each WCLK cycle. The output port is controlled in a similar
manner by a free running read clock (RCLK) and two read enable
pins (REN1, REN2). In addition, the CY7C4261/71 has an output
enable pin (OE). The read (RCLK) and write (WCLK) clocks may
be tied together for single-clock operation or the two clocks may
be run independently for asynchronous read/write applications.
Clock frequencies up to 100 MHz are achievable. Depth
expansion is possible using one enable input for system control,
while the other enable is controlled by expansion logic to direct
the flow of data.
Selection Guide
Parameter
7C4261/71-10
7C4261/71-15
7C4261/71-25
7C4261/71-35
Unit
100
66.7
40
28.6
MHz
Maximum Access Time
8
10
15
20
ns
Minimum Cycle Time
10
15
25
35
ns
Maximum Frequency
Minimum Data or Enable Setup
3
4
6
7
ns
Minimum Data or Enable Hold
0.5
1
1
2
ns
Maximum Flag Delay
8
10
15
20
ns
Active Power Supply Commercial
Current (ICC1)
Industrial/
Military
35
35
35
35
mA
40
40
40
40
Parameter
CY7C4261
CY7C4271
Density
16K × 9
32K × 9
Package
32-pin PLCC, TQFP
32-pin LCC, PLCC, TQFP
Cypress Semiconductor Corporation
Document #: 38-06015 Rev. *D
•
198 Champion Court
•
San Jose, CA 95134-1709
•
408-943-2600
Revised August 22, 2008
[+] Feedback
CY7C4261, CY7C4261
Logic Block Diagram
D0–8
INPUT
REGISTER
WCLK WEN1 WEN2/LD
FLAG
PROGRAM
REGISTER
WRITE
CONTROL
FLAG
LOGIC
WRITE
POINTER
RS
RAM
ARRAY
16K x 9
32K x 9
EF
PAE
PAF
FF
READ
POINTER
RESET
LOGIC
THREE-STATE
OUTPUT REGISTER
READ
CONTROL
OE
Q0–8
Document #: 38-06015 Rev. *D
RCLK REN1 REN2
Page 2 of 19
[+] Feedback
CY7C4261, CY7C4261
Pinouts
D8
RS
D7
D6
D5
32 31 30 29 28 27 26 25
RS
WEN1
WCLK
WEN2/LD
VCC
Q8
Q7
Q6
Q5
D1
1
24
WEN1
D0
2
23
WCLK
PAF
3
22
WEN2/LD
PAE
4
21
GND
5
REN1
6
19
VCC
Q8
Q7
RCLK
7
18
Q6
REN2
8
17
Q5
CY7C4261
CY7C4271
20
9 10 11 12 13 14 15 16
Q3
Q4
Q2
Q1
Q0
FF
EF
OE
Q3
Q4
EF
FF
Q0
Q1
Q2
REN1
RCLK
REN2
OE
4 3 2 1 32 31 30
29
5
28
6
27
7
8
CY7C4261 26
9
25
CY7C4271 24
10
11
23
22
12
21
13
14 15 16 17 18 19 20
D4
D2
D3
D4
D5
D6
D7
D8
D1
D0
PAF
PAE
GND
D3
Figure 2. Pin Diagram - 32-Pin TQFP (Top View)
D2
Figure 1. Pin Diagram - 32-Pin PLCC/LCC (Top View)
Table 1. Pin Definitions - 32-Pin Device
Signal Name
Description
IO
Description
D0−8
Data Inputs
I
Data Inputs for 9-bit bus.
Q0−8
Data Outputs
O
Data Outputs for 9-bit bus.
WEN1
Write Enable 1
I
The only write enable when device is configured to have programmable flags. Data is written
on a LOW-to-HIGH transition of WCLK when WEN1 is asserted and FF is HIGH. If the FIFO
is configured to have two write enables, data is written on a LOW-to-HIGH transition of WCLK
when WEN1 is LOW and WEN2/LD and FF are HIGH.
Write Enable 2
WEN2/LD
Dual Mode Pin Load
I
If HIGH at reset, this pin operates as a second write enable. If LOW at reset, this pin operates
as a control to write or read the programmable flag offsets. WEN1 must be LOW and WEN2
must be HIGH to write data into the FIFO. Data is not written into the FIFO if the FF is LOW.
If the FIFO is configured to have programmable flags, WEN2/LD is held LOW to write or read
the programmable flag offsets.
REN1, REN2
Read Enable
Inputs
I
Enables the device for Read operation. Both REN1 and REN2 must be asserted to allow a
read operation.
WCLK
Write Clock
I
The rising edge clocks data into the FIFO when WEN1 is LOW and WEN2/LD is HIGH and
the FIFO is not Full. When LD is asserted, WCLK writes data into the programmable
flag-offset register.
RCLK
Read Clock
I
The rising edge clocks data out of the FIFO when REN1 and REN2 are LOW and the FIFO
is not Empty. When WEN2/LD is LOW, RCLK reads data out of the programmable flag-offset
register.
EF
Empty Flag
O
When EF is LOW, the FIFO is empty. EF is synchronized to RCLK.
FF
Full Flag
O
When FF is LOW, the FIFO is full. FF is synchronized to WCLK.
PAE
Programmable
Almost Empty
O
When PAE is LOW, the FIFO is almost empty based on the almost empty offset value
programmed into the FIFO. PAE is synchronized to RCLK.
PAF
Programmable
Almost Full
O
When PAF is LOW, the FIFO is almost full based on the almost full offset value programmed
into the FIFO. PAF is synchronized to WCLK.
RS
Reset
I
Resets device to empty condition. A reset is required before an initial read or write operation
after power up.
OE
Output Enable
I
When OE is LOW, the FIFO’s data outputs drive the bus to which they are connected. If OE
is HIGH, the FIFO’s outputs are in High Z (high impedance) state.
Document #: 38-06015 Rev. *D
Page 3 of 19
[+] Feedback
CY7C4261, CY7C4261
Functional Description
The CY7C4261/71 provides four status pins: Empty, Full,
Programmable Almost Empty, and Programmable Almost Full.
The Almost Empty/Almost Full flags are programmable to single
word granularity. The programmable flags default to Empty + 7
and Full – 7.
The flags are synchronous, that is, they change state relative to
either the read clock (RCLK) or the write clock (WCLK). When
entering or exiting the Empty and Almost Empty states, the flags
are updated exclusively by the RCLK. The flags denoting Almost
Full, and Full states are updated exclusively by WCLK. The
synchronous flag architecture guarantees that the flags maintain
their status for at least one cycle.
All configurations are fabricated using an advanced 0.5μ CMOS
technology. Input ESD protection is greater than 2001V, and
latch-up is prevented by the use of guard rings.
Architecture
The CY7C4261/71 consists of an array of 16K to 32K words of
nine bits each (implemented by a dual port array of SRAM cells),
a read pointer, a write pointer, control signals (RCLK, WCLK,
REN1, REN2, WEN1, WEN2, RS), and flags (EF, PAE, PAF, FF).
Resetting the FIFO
Upon power up, the FIFO must be reset with a Reset (RS) cycle.
This causes the FIFO to enter the Empty condition signified by
EF being LOW. All data outputs (Q0−8) go LOW tRSF after the
rising edge of RS. For the FIFO to reset to its default state, a
falling edge must occur on RS and the user must not read or write
while RS is LOW. All flags are guaranteed to be valid tRSF after
RS is taken LOW.
FIFO Operation
When the WEN1 signal is active LOW, WEN2 is active HIGH,
and FF is active HIGH, data present on the D0−8 pins is written
into the FIFO on each rising edge of the WCLK signal. Similarly,
when the REN1 and REN2 signals are active LOW and EF is
active HIGH, data in the FIFO memory is presented on the Q0−8
outputs. New data is presented on each rising edge of RCLK
while REN1 and REN2 are active. REN1 and REN2 must set up
tENS before RCLK for it to be a valid read function. WEN1 and
WEN2 must occur tENS before WCLK for it to be a valid write
function.
An output enable (OE) pin is provided to three-state the Q0−8
outputs when OE is asserted. When OE is enabled (LOW), data
in the output register is available to the Q0−8 outputs after tOE. If
devices are cascaded, the OE function only outputs data on the
FIFO that is read enabled.
The FIFO contains overflow circuitry to disallow additional writes
when the FIFO is full, and underflow circuitry to disallow
additional reads when the FIFO is empty. An empty FIFO
maintains the data of the last valid read on its Q0−8 outputs even
after additional reads occur.
Document #: 38-06015 Rev. *D
Write Enable 1 (WEN1). If the FIFO is configured for
programmable flags, Write Enable 1 (WEN1) is the only write
enable control pin. In this configuration, when Write Enable 1
(WEN1) is LOW, data can be loaded into the input register and
RAM array on the LOW-to-HIGH transition of every write clock
(WCLK). Data is stored is the RAM array sequentially and
independently of any on-going read operation.
Write Enable 2/Load (WEN2/LD). This is a dual purpose pin.
The FIFO is configured at Reset to have programmable flags or
to have two write enables, which allows for depth expansion. If
Write Enable 2/Load (WEN2/LD) is set active HIGH at Reset (RS
= LOW), this pin operates as a second write enable pin.
If the FIFO is configured to have two write enables, when Write
Enable (WEN1) is LOW and Write Enable 2/Load (WEN2/LD) is
HIGH, data can be loaded into the input register and RAM array
on the LOW-to-HIGH transition of every write clock (WCLK).
Data is stored in the RAM array sequentially and independently
of any ongoing read operation.
Programming
When WEN2/LD is held LOW during Reset, this pin is the load
(LD) enable for flag offset programming. In this configuration,
WEN2/LD can be used to access the four 8-bit offset registers
contained in the CY7C4261/71 for writing or reading data to
these registers.
When the device is configured for programmable flags and both
WEN2/LD and WEN1 are LOW, the first LOW-to-HIGH transition
of WCLK writes data from the data inputs to the empty offset least
significant bit (LSB) register. The second, third, and fourth
LOW-to-HIGH transitions of WCLK store data in the empty offset
most significant bit (MSB) register, full offset LSB register, and
full offset MSB register, respectively, when WEN2/LD and WEN1
are LOW. The fifth LOW-to-HIGH transition of WCLK while
WEN2/LD and WEN1 are LOW writes data to the empty LSB
register again. Figure 3 shows the register sizes and default
values for the various device types.
Figure 3. Offset Register Location and Default Values
16K × 9
8
32K × 9
0
7
8
Empty Offset (LSB) Reg.
Default Value = 007h
Empty Offset (LSB) Reg.
Default Value = 007h
0
5
8
0
7
(MSB)
000000
8
(MSB)
0000000
0
7
8
Full Offset (LSB) Reg
Default Value = 007h
8
(MSB)
000000
0
7
Full Offset (LSB) Reg
Default Value = 007h
0
5
0
6
8
8
0
6
(MSB)
0000000
Page 4 of 19
[+] Feedback
CY7C4261, CY7C4261
It is not necessary to write to all the offset registers at one time.
A subset of the offset registers can be written, and then by
bringing the WEN2/LD input HIGH, the FIFO is returned to
normal read and write operation. The next time WEN2/LD is
brought LOW, a write operation stores data in the next offset
register in sequence.
The contents of the offset registers can be read to the data
outputs when WEN2/LD is LOW and both REN1 and REN2 are
LOW. LOW-to-HIGH transitions of RCLK read register contents
to the data outputs. Writes and reads must not be performed
simultaneously on the offset registers.
Programmable Flag (PAE, PAF) Operation
Whether the flag offset registers are programmed as described
in Table 2 or the default values are used, the programmable
almost-empty flag (PAE) (PAF) states are determined by their
corresponding offset registers and the difference between the
read and write pointers.
Table 2. Writing the Offset Registers
LD
WEN
0
0
WCLK[1]
Selection
Empty Offset (LSB)
Empty Offset (MSB)
Full Offset (LSB)
Full Offset (MSB)
0
1
No Operation
1
0
Write Into FIFO
1
1
No Operation
Table 3. Status Flags
Number of Words in FIFO
CY7C4261
0
CY7C4271
FF PAF PAE EF
H
H
L
L
H
H
L
H
H
H
H
H
(16384 − m)[3] to 16383 (32768 − m)[3] to 32767 H
L
H
H
16384
L
H
H
1 to n
0
[2]
(n + 1) to
(16384 − (m + 1))
1 to n
[2]
(n + 1) to
(32768 − (m + 1))
32768
L
Width Expansion Configuration
Word width may be increased by simply connecting the
corresponding input controls signals of multiple devices. A
composite flag must be created for each of the end-point status
flags (EF and FF). The partial status flags (PAE and PAF) can be
detected from any one device. Figure 4 on page 6 demonstrates
a 18-bit word width by using two CY7C4261/71s. Any word width
can be attained by adding additional CY7C4261/71s.
When the CY7C4261/71 is in a Width Expansion Configuration,
the Read Enable (REN2) control input can be grounded (see
Figure 4 on page 6). In this configuration, the Write Enable
2/Load (WEN2/LD) pin is set to LOW at Reset so that the pin
operates as a control to load and read the programmable flag
offsets.
Flag Operation
The CY7C4261/71 devices provide four flag pins to indicate the
condition of the FIFO contents. Empty, Full, PAE, and PAF are
synchronous.
Full Flag
The number formed by the empty offset least significant bit
register and empty offset most significant bit register is referred
to as n and determines the operation of PAE. PAF is synchronized
to the LOW-to-HIGH transition of RCLK by one flip-flop and is
LOW when the FIFO contains n or fewer unread words. PAE is
set HIGH by the LOW-to-HIGH transition of RCLK when the
FIFO contains (n+1) or greater unread words.
The number formed by the full offset least significant bit register
and full offset most significant bit register is referred to as m and
determines the operation of PAF. PAE is synchronized to the
LOW-to-HIGH transition of WCLK by one flip-flop and is set LOW
when the number of unread words in the FIFO is greater than or
equal to CY7C4261 (16K-m) and CY7C4271 (32K-m). PAF is set
HIGH by the LOW-to-HIGH transition of WCLK when the number
of available memory locations is greater than m.
The Full Flag (FF) goes LOW when the device is full. Write
operations are inhibited whenever FF is LOW regardless of the
state of WEN1 and WEN2/LD. FF is synchronized to WCLK, that
is, it is exclusively updated by each rising edge of WCLK.
Empty Flag
The Empty Flag (EF) goes LOW when the device is empty. Read
operations are inhibited whenever EF is LOW, regardless of the
state of REN1 and REN2. EF is synchronized to RCLK, that is, it
is exclusively updated by each rising edge of RCLK.
Notes
1. The same selection sequence applies to reading from the registers. REN1 and REN2 are enabled and a read is performed on the LOW-to-HIGH transition of RCLK.
2. n = Empty Offset (n = 7 default value).
3. m = Full Offset (m = 7 default value).
Document #: 38-06015 Rev. *D
Page 5 of 19
[+] Feedback
CY7C4261, CY7C4261
Figure 4. Block Diagram of 16K × 18/32K × 18 Deep Sync FIFO Memory Used in a Width Expansion Configuration
RESET (RS)
DATAIN (D) 18
RESET (RS)
9
9
READ CLOCK (RCLK)
WRITECLOCK (WCLK)
READ ENABLE 1 (REN1)
WRITE ENABLE 1(WEN1)
OUTPUT ENABLE (OE)
WRITE ENABLE 2/LOAD
(WEN2/LD)
PROGRAMMABLE(PAF)
CY7C4261/71
CY7C4261/71
EMPTY FLAG (EF) #2
FULL FLAG (FF) # 1
FF
FF
EF
EF
9
FULL FLAG (FF) # 2
DATA OUT (Q)
18
9
Read Enable 2 (REN2)
Document #: 38-06015 Rev. *D
PROGRAMMABLE(PAE)
EMPTY FLAG (EF) #1
Read Enable 2 (REN2)
Page 6 of 19
[+] Feedback
CY7C4261, CY7C4261
Maximum Ratings
Static Discharge Voltage............................................ >2001V
(per MIL-STD-883, Method 3015)
Exceeding maximum ratings[4] may impair the useful life of the
device. These user guidelines are not tested.
Latch-up Current...................................................... >200 mA
Operating Range
Storage Temperature .......................................−65°C to +150°C
Ambient Temperature with
Power Applied....................................................−55°C to +125°C
Ambient Temperature
VCC
Commercial
Range
0°C to +70°C
5V ± 10%
Supply Voltage to Ground Potential .................−0.5V to +7.0V
Industrial[5]
−40°C to +85°C
5V ± 10%
DC Voltage Applied to Outputs
in High-Z State ........................................... −0.5V to VCC + 0.5V
Military
−55°C to +125°C
5V ± 10%
DC Input Voltage ....................................... −0.5V to VCC + 0.5V
Output Current into Outputs (LOW) ............................. 20 mA
Electrical Characteristics
Over the Operating Range [6]
Parameter
Description
Test Conditions
7C4261/71-10 7C4261/71-15 7C4261/71-25 7C4261/71-35
Min
Max
2.4
Min
Max
2.4
Min
Max
2.4
Min
Max
VOH
Output HIGH Voltage
VCC = Min,
IOH = −2.0 mA
VOL
Output LOW Voltage
VCC = Min,
IOL = 8.0 mA
VIH
Input HIGH Voltage
(Commercial/Industrial)
2.0
VCC
2.0
VCC
2.0
VCC
VIH
Input HIGH Voltage
(Military)
2.2
VCC
2.2
VCC
2.2
VIL
Input LOW Voltage
−0.5
0.8
−0.5
0.8
IIX
Input Leakage Current
VCC = Max.
−10
+10
−10
+10
IOZL
IOZH
Output OFF,
High Z Current
OE > VIH,
VSS < VO< VCC
−10
+10
−10
+10
ICC1[7]
Active Power Supply
Current
Com’l
Ind/Mil
40
40
40
40
mA
ISB[8]
Average Standby Current
Com’l
10
10
10
10
mA
Ind/Mil
15
15
15
15
mA
0.4
0.4
35
2.4
Unit
0.4
V
0.4
V
2.0
VCC
V
VCC
2.2
VCC
V
−0.5
0.8
−0.5
0.8
V
−10
+10
−10
+10
μA
−10
+10
−10
+10
μA
35
mA
35
35
Capacitance
Parameter[9]
Description
CIN
Input Capacitance
COUT
Output Capacitance
Test Conditions
TA = 25°C, f = 1 MHz,
VCC = 5.0V
Max
Unit
5
pF
7
pF
Notes
4. The voltage on any input or IO pin cannot exceed the power pin during power up.
5. TA is the “instant on” case temperature.
6. See the last page of this specification for Group A subgroup testing information.
7. Input signals switch from 0V to 3V with a rise/fall time of less than 3 ns, clocks and clock enables switch at maximum frequency 20 MHz, while data inputs switch at
10 MHz. Outputs are unloaded. ICC1(typical) = (20 mA + (freq – 20 MHz) * (0.7 mA/MHz)).
8. All inputs = VCC – 0.2V, except WCLK and RCLK (which are switching at frequency = 20 MHz). All outputs are unloaded.
9. Tested initially and after any design or process changes that may affect these parameters.
Document #: 38-06015 Rev. *D
Page 7 of 19
[+] Feedback
CY7C4261, CY7C4261
Figure 5. AC Test Loads and Waveforms [10, 11]
R1 1.1KΩ
ALL INPUT PULSES
5V
OUTPUT
3.0V
GND
≤3 ns
R2
680Ω
INCLUDING CL
JIG AND
SCOPE
90%
10%
90%
10%
≤ 3 ns
Equivalent to:
THÉVENIN EQUIVALENT
420Ω
OUTPUT
1.91V
Switching Characteristics
Over the Operating Range
Parameter
Description
7C4261/71-10
7C4261/71-15
7C4261/71-25
Min
Min
Min
Max
Max
Max
7C4261/71- 35
Min
Max
Unit
tS
Clock Cycle Frequency
tA
Data Access Time
2
tCLK
Clock Cycle Time
10
15
25
35
ns
tCLKH
Clock HIGH Time
4.5
6
10
14
ns
tCLKL
Clock LOW Time
4.5
6
10
14
ns
tDS
Data Setup Time
3
4
6
7
ns
tDH
Data Hold Time
0.5
1
1
2
ns
tENS
Enable Setup Time
3
4
6
7
ns
tENH
Enable Hold Time
0.5
1
1
2
ns
10
15
25
35
ns
100
Width[12]
8
66.7
2
10
40
2
15
28.6
2
20
MHz
ns
tRS
Reset Pulse
tRSS
Reset Setup Time
8
10
15
20
ns
tRSR
Reset Recovery Time
8
10
15
20
ns
tRSF
Reset to Flag and Output Time
tOLZ
Output Enable to Output in Low
tOE
Output Enable to Output Valid
10
Z[13]
Z[13]
0
15
0
25
0
35
0
ns
ns
3
7
3
8
3
12
3
15
ns
3
7
3
8
3
12
3
15
ns
tOHZ
Output Enable to Output in High
tWFF
Write Clock to Full Flag
8
10
15
20
ns
tREF
Read Clock to Empty Flag
8
10
15
20
ns
tPAF
Clock to Programmable Almost Full Flag
8
10
15
20
ns
tPAE
Clock to Programmable Almost Full Flag
8
10
15
20
ns
tSKEW1
Skew Time between Read Clock and Write
Clock for Empty Flag and Full Flag
5
6
10
12
ns
tSKEW2
Skew Time between Read Clock and Write Clock
for Almost Empty Flag and Almost Full Flag
10
15
18
20
ns
Notes
10. 5CL = 30 pF for all AC parameters except for tOHZ.
11. 5CL = 5 pF for tOHZ.
12. Pulse widths less than minimum values are not allowed.
13. Values guaranteed by design, not currently tested.
Document #: 38-06015 Rev. *D
Page 8 of 19
[+] Feedback
CY7C4261, CY7C4261
Switching Waveforms
Figure 6. Write Cycle Timing
tCLK
tCLKH
tCLKL
WCLK
tDS
tDH
D0 –D17
tENS
tENH
WEN1
NO OPERATION
NO OPERATION
WEN2
(if applicable)
tWFF
tWFF
FF
tSKEW1
[14]
RCLK
REN1, REN2
Figure 7. Read Cycle Timing
tCKL
tCLKH
tCLKL
RCLK
tENS
tENH
REN1, REN2
NO OPERATION
tREF
tREF
EF
tA
Q0 –Q17
VALID DATA
tOLZ
tOHZ
tOE
OE
tSKEW1[15]
WCLK
WEN1
WEN2
Notes
14. tSKEW1 is the minimum time between a rising RCLK edge and a rising WCLK edge to guarantee that FF goes HIGH during the current clock cycle. If the time between
the rising edge of RCLK and the rising edge of WCLK is less than tSKEW1, then FF may not change state until the next WCLK rising edge.
15. tSKEW1 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that EF goes HIGH during the current clock cycle. It the time between
the rising edge of WCLK and the rising edge of RCLK is less than tSKEW2, then EF may not change state until the next RCLK rising edge.
Document #: 38-06015 Rev. *D
Page 9 of 19
[+] Feedback
CY7C4261, CY7C4261
Switching Waveforms
(continued)
Figure 8. Reset Timing [16]
tRS
RS
tRSS
tRSR
tRSS
tRSR
tRSS
tRSR
REN1,
REN2
WEN1
WEN2/LD [18]
tRSF
EF,PAE
tRSF
FF,PAF
tRSF
OE = 1[17]
Q0 - Q8
OE = 0
Figure 9. First Data Word Latency after Reset with Read and Write
WCLK
tDS
D0 –D8
D0(FIRST VALID WRITE)
D1
D2
D3
D4
tENS
tFRL [19]
WEN1
WEN2
(if applicable)
tSKEW1
RCLK
tREF
EF
tA
[20]
tA
REN1,
REN2
Q0 –Q8
D0
D1
tOLZ
tOE
OE
Notes
16. The clocks (RCLK, WCLK) can be free running during reset.
17. After reset, the outputs are LOW if OE = 0 and three-state if OE = 1.
18. Holding WEN2/LD HIGH during reset makes the pin act as a second enable pin. Holding WEN2/LD LOW during reset makes the pin act as a load enable for the
programmable flag offset registers.
19. When tSKEW1 > minimum specification, tFRL (maximum) = tCLK + tSKEW2. When tSKEW2 < minimum specification, tFRL (maximum) = either 2*tCLK + tSKEW1 or tCLK +
tSKEW1. The Latency Timing applies only at the Empty Boundary (EF = LOW).
20. The first word is available the cycle after EF goes HIGH, always.
Document #: 38-06015 Rev. *D
Page 10 of 19
[+] Feedback
CY7C4261, CY7C4261
Switching Waveforms
(continued)
Figure 10. Empty Flag Timing
WCLK
tDS
tDS
DATA WRITE 2
DATA WRITE 1
D0 –D8
tENH
tENS
tENH
tENS
WEN1
tENS
tENH
tENH
tENS
WEN2
(if applicable)
tFRL
[19]
tFRL
[19]
RCLK
tREF
tREF
tSKEW1
tREF
tSKEW1
EF
REN1,
REN2
LOW
OE
tA
DATA IN OUTPUT REGISTER
Q0 –Q8
DATA READ
Figure 11. Full Flag Timing
NO WRITE
NO WRITE
WCLK
tSKEW1[14]
[14]
tDS
DATA WRITE
tSKEW1
DATA WRITE
D0 –D8
tWFF
tWFF
tWFF
FF
WEN1
WEN2
(if applicable)
RCLK
tENH
OE
tENH
tENS
REN1,
REN2
tENS
LOW
tA
tA
Q0 –Q8
DATA IN OUTPUT REGISTER
Document #: 38-06015 Rev. *D
DATA READ
NEXT DATA READ
Page 11 of 19
[+] Feedback
CY7C4261, CY7C4261
Switching Waveforms
(continued)
Figure 12. Programmable Almost Empty Flag Timing
tCLKL
tCLKH
WCLK
tENS tENH
WEN1
WEN2
(if applicable)
tENS tENH
22
PAE
tESKEW2[21]
N + 1 WORDS
IN FIFO
23 t
PAE
tPAE
RCLK
tENS
tENS tENH
REN1,
REN2
Figure 13. Programmable Almost Full Flag Timing
tCLKH
tCLKL
Note
24
WCLK
tENS tENH
WEN1
WEN2
(if applicable)
25
tENS tENH
PAF
tPAF
FULL − M WORDS
IN FIFO [26]
FULL − (M + 1) WORDS
IN FIFO
tSKEW2 [27]
tPAF
RCLK
tENS
tENS tENH
REN1,
REN2
Notes
21. tSKEW2 is the minimum time between a rising WCLK and a rising RCLK edge for PAE to change state during that clock cycle. If the time between the edge of WCLK
and the rising RCLK is less than tSKEW2, then PAE may not change state until the next RCLK.
22. PAE offset= n.
23. If a read is preformed on this rising edge of the read clock, there are Empty + (n−1) words in the FIFO when PAE goes LOW
24. If a write is performed on this rising edge of the write clock, there are Full − (m−1) words of the FIFO when PAF goes LOW.
25. PAF offset = m.
26. 16,384 − m words for CY7C4261, 32,768 − m words for CY7C4271.
27. tSKEW2 is the minimum time between a rising RCLK edge and a rising WCLK edge for PAF to change during that clock cycle. If the time between the rising edge of
RCLK and the rising edge of WCLK is less than tSKEW2, then PAF may not change state until the next WCLK.
Document #: 38-06015 Rev. *D
Page 12 of 19
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CY7C4261, CY7C4261
Switching Waveforms
(continued)
Figure 14. Write Programmable Registers
tCLK
tCLKL
tCLKH
WCLK
tENS
tENH
WEN2/LD
tENS
WEN1
tDS
tDH
D0 –D8
PAE OFFSET
LSB
PAE OFFSET
MSB
PAF OFFSET
LSB
PAF OFFSET
MSB
Figure 15. Read Programmable Registers
tCLK
tCLKL
tCLKH
RCLK
tENS
tENH
WEN2/LD
tENS
PAF OFFSET
MSB
REN1,
REN2
tA
Q0 –Q15
Document #: 38-06015 Rev. *D
UNKNOWN
PAE OFFSET LSB
PAE OFFSET MSB
PAF OFFSET
LSB
Page 13 of 19
[+] Feedback
CY7C4261, CY7C4261
Figure 16. Typical AC and DC Characteristics
NORMALIZED tA vs. AMBIENT
TEMPERATURE
NORMALIZED tA vs. SUPPLY
VOLTAGE
1.60
NORMALIZED tA
NORMALIZED tA
1.20
1.10
1.00
0.90
TA = 25°C
0.80
4.00
4.50
5.00
6.00
5.50
1.40
1.20
1.00
0.60
−55.00
1.00
VIN = 3.0V
TA = 25°C
f = 28 MHz
0.80
4.50
5.00
5.50
SUPPLY VOLTAGE (V)
Document #: 38-06015 Rev. *D
6.00
125.00
1.75
NORMALIZED ICC
NORMALIZED ICC
NORMALIZED ICC
1.20
1.20
65.00
NORMALIZED SUPPLY CURRENT
vs. FREQUENCY
NORMALIZED SUPPLY CURRENT
vs. AMBIENT TEMPERATURE
1.40
0.60
4.00
5.00
AMBIENT TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
NORMALIZED SUPPLY CURRENT
vs. SUPPLY VOLTAGE
VCC = 5.0V
0.80
1.10
1.00
VIN = 3.0V
VCC = 5.0V
f = 28 MHz
0.90
0.80
−55.00
5.00
65.00
125.00
AMBIENT TEMPERATURE (°C)
1.50
1.25
1.00
VCC = 5.0V
TA = 25°C
VIN = 3.0V
0.75
0.50
20.00
30.00
40.00
50.00
60.00
FREQUENCY (MHz)
Page 14 of 19
[+] Feedback
CY7C4261, CY7C4261
Ordering Information
16Kx9 Deep Sync FIFO
Speed (ns)
10
Ordering Code
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4261-10JC
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4261-10AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4261-10JXI
CY7C4261-15AC
CY7C4261-15JC
25
35
Package Type
CY7C4261-10AC
CY7C4261-10JI
15
Package Diagram
CY7C4261-15JXC
51-85002
51-85063
51-85002
32-Pin Plastic Leaded Chip Carrier
Operating Range
Commercial
Industrial
32-Pin Plastic Leaded Chip Carrier (Pb-Free)
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
32-Pin Plastic Leaded Chip Carrier
Commercial
32-Pin Plastic Leaded Chip Carrier (Pb-Free)
CY7C4261-15AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4261-15JI
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4261-25AC
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4261-25JC
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4261-25AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4261-25JI
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4261-35AC
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4261-35JC
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4261-35AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4261-35JI
51-85002
32-Pin Plastic Leaded Chip Carrier
Industrial
Commercial
Industrial
Commercial
Industrial
32Kx9 Deep Sync FIFO
Speed (ns)
10
15
Ordering Code
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4271-10JC
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4271-10AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4271-10JI
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4271-15AC
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4271-15AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4271-15JI
51-85002
32-Pin Plastic Leaded Chip Carrier
51-80068
32-Pin Rectangular Leadless Chip Carrier
CY7C4271-25AC
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4271-25JC
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4271-25AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4271-25JI
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4271-35AC
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4271-35JC
51-85002
32-Pin Plastic Leaded Chip Carrier
CY7C4271-35AI
51-85063
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm)
CY7C4271-35JI
51-85002
32-Pin Plastic Leaded Chip Carrier
5962-9736101QYA
Document #: 38-06015 Rev. *D
Operating Range
Commercial
Industrial
Commercial
32-Pin Thin Quad Flat Pack (7 x 7 x 1.0 mm) (Pb-Free)
CY7C4271-15JC
CY7C4271-15LMB
35
Package Type
51-85063
CY7C4271-15AXC
25
Package Diagram
CY7C4271-10AC
Industrial
Military
Commercial
Industrial
Commercial
Industrial
Page 15 of 19
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CY7C4261, CY7C4261
Table 5. Switching Characteristics (continued)
Table 4. DC Characteristics
Parameters
Subgroups
Parameters
Subgroups
VOH
1, 2, 3
tRFF
9, 10, 11
VOL
1, 2, 3
tWEF
9, 10, 11
VIH
1, 2, 3
tWFF
9, 10, 11
VIL Max.
1, 2, 3
tWHF
9, 10, 11
IIX
1, 2, 3
tRHF
9, 10, 11
ICC
1, 2, 3
tRAE
9, 10, 11
ICC1
1, 2, 3
tRPE
9, 10, 11
ISB1
1, 2, 3
tWAF
9, 10, 11
ISB2
1, 2, 3
tWPF
9, 10, 11
IOS
1, 2, 3
tXOL
9, 10, 11
tXOH
9, 10, 11
Table 5. Switching Characteristics
Parameters
Subgroups
tRC
9, 10, 11
tA
9, 10, 11
tRR
9, 10, 11
tPR
9, 10, 11
tDVR
9, 10, 11
tWC
9, 10, 11
tPW
9, 10, 11
tWR
9, 10, 11
tSD
9, 10, 11
tHD
9, 10, 11
tMRSC
9, 10, 11
tPMR
9, 10, 11
tRMR
9, 10, 11
tRPW
9, 10, 11
tWPW
9, 10, 11
tRTC
9, 10, 11
tPRT
9, 10, 11
tRTR
9, 10, 11
tEFL
9, 10, 11
tHFH
9, 10, 11
tFFH
9, 10, 11
tREF
9, 10, 11
Document #: 38-06015 Rev. *D
Page 16 of 19
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CY7C4261, CY7C4261
Package Diagrams
Figure 17. 32-Pin Thin Plastic Quad Flatpack (7 × 7 × 1.0 mm)
51-85063 *B
Figure 18. 32-Pin Plastic Leaded Chip Carrier
51-85002 *B
Document #: 38-06015 Rev. *D
Page 17 of 19
[+] Feedback
CY7C4261, CY7C4261
Package Diagrams (continued)
Figure 19. 32-Pin Rectangular Leadless Chip Carrier
MIL-STD-1835 C-12
51-80068-**
Document #: 38-06015 Rev. *D
Page 18 of 19
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CY7C4261, CY7C4261
Document History Page
Document Title: CY7C4261/CY7C4271, 16K/32K x 9 Deep Sync FIFOs
Document Number: 38-06015
REV.
ECN
Orig. of
Change
Submission
Date
**
106476
SZV
09/10/01
Changed from Spec number: 38-00658 to 38-06015
*A
122267
RBI
12/26/02
Added power up requirements Maximum Ratings Information
*B
127853
FSG
08/22/03
Switching Waveforms section: fixed misplaced footnote in tA in “First Data
Word Latency after Reset with Read and Write” drawing
Switching Waveforms section: changed tSKEW2 to tSKEW1 (typo) in “Empty Flag
Timing” drawing
*C
393437
ESH
See ECN
Added Pb-Free Logo to top of front page
Added CY7C4261-10JXI, CY7C4261-15JXC to ordering information
*D
2556036
VKN/AESA
08/22/2008
Description of Change
Updated ordering information and data sheet template. Removed Pb-Free
Logo.
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United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create derivative works of,
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Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not
assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where
a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer
assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Use may be limited by and subject to the applicable Cypress software license agreement.
Document #: 38-06015 Rev. *D
Revised August 22, 2008
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