IDT IDT7285L12PA

IDT7280
IDT7281
IDT7282
IDT7283
IDT7284
IDT7285
CMOS DUAL ASYNCHRONOUS FIFO
DUAL 256 x 9, DUAL 512 x 9,
DUAL 1,024 x 9, DUAL 2,048 x 9,
DUAL 4,096 x 9, DUAL 8,192 x 9
FEATURES:
DESCRIPTION:
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•
The IDT7280/7281/7282/7283/7284/7285 are dual-FIFO memories that
load and empty data on a first-in/first-out basis. These devices are functional
and compatible to two IDT7200/7201/7202/7203/7204/7205 FIFOs in a single
package with all associated control, data, and flag lines assigned to separate
pins. The devices use Full and Empty flags to prevent data overflow and
underflow and expansion logic to allow for unlimited expansion capability in both
word size and depth.
The reads and writes are internally sequential through the use of ring pointers,
with no address information required to load and unload data. Data is toggled
in and out of the devices through the use of the Write (W) and Read (R) pins.
The devices utilize a 9-bit wide data array to allow for control and parity bits
at the user’s option. This feature is especially useful in data communications
applications where it is necessary to use a parity bit for transmission/reception
error checking. It also features a Retransmit (RT) capability that allows for reset
of the read pointer to its initial position when RT is pulsed LOW to allow for
retransmission from the beginning of data. A Half-Full Flag is available in the
single device mode and width expansion modes.
These FIFOs are fabricated using IDT’s high-speed CMOS technology.
They are designed for those applications requiring asynchronous and simultaneous read/writes in multiprocessing and rate buffer applications.
•
•
•
•
•
•
•
•
•
•
•
•
•
The IDT7280 is equivalent to two IDT7200 256 x 9 FIFOs
The IDT7281 is equivalent to two IDT7201 512 x 9 FIFOs
The IDT7282 is equivalent to two IDT7202 1,024 x 9 FIFOs
The IDT7283 is equivalent to two IDT7203 2,048 x 9 FIFOs
The IDT7284 is equivalent to two IDT7204 4,096 x 9 FIFOs
The IDT7285 is equivalent to two IDT7205 8,192 x 9 FIFOs
Low power consumption
— Active: 685 mW (max.)
— Power-down: 83 mW (max.)
Ultra high speed—12 ns access time
Asynchronous and simultaneous read and write
Offers optimal combination of data capacity, small foot print
and functional flexibility
Ideal for bi-directional, width expansion, depth expansion,
bus-matching, and data sorting applications
Status Flags: Empty, Half-Full, Full
Auto-retransmit capability
High-performance CMOS technology
Space-saving TSSOP
Industrial temperature range (–40°°C to +85°°C) is available
FUNCTIONAL BLOCK DIAGRAM
DATA INPUTS
(DA0-DA8)
WA
WRITE
CONTROL
RAM
ARRAY A
256 x 9
512 x 9
1,024 x 9
2,048 x 9
4,096 x 9
8,192 x 9
WRITE
POINTER
RSA
DATA INPUTS
(DB0-DB8)
WB
WRITE
CONTROL
WRITE
POINTER
READ
POINTER
READ
CONTROL
READ
CONTROL
RESET
LOGIC
FLAG
LOGIC
XOA/HFA
RESET
LOGIC
FLAG
LOGIC
EXPANSION
LOGIC
XIA
READ
POINTER
THREESTATE
BUFFERS
THREESTATE
BUFFERS
RA
RAM
ARRAY B
256 x 9
512 x 9
1,024 x 9
2,048 x 9
4,096 x 9
8,192 x 9
RSB
EXPANSION
LOGIC
FFA
EFA
DATA
OUTPUTS
(QA0-QA8)
RB
FLA/RTA
XIB
XOB/HFB
FFB
EFB
DATA
OUTPUTS
(QB0-QB8)
FLB/RTB
3208 drw 01
IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
SEPTEMBER 2002
1
2002 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.
DSC-3208/5
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
PIN CONFIGURATION
FFA
QA0
QA1
QA2
QA3
QA8
GND
RA
QA4
QA5
QA6
QA7
XOA/HFA
EFA
FFB
QB0
QB1
QB2
QB3
QB8
GND
RB
QB4
QB5
QB6
QB7
XOB/HFB
EFB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
COMMERCIAL TEMPERATURE RANGE
ABSOLUTE MAXIMUM RATINGS
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
Symbol
VTERM
XIA
DA0
DA1
DA2
DA3
DA8
WA
VCC
DA4
DA5
DA6
DA7
FLA/RTA
RSA
XIB
DB0
DB1
DB2
DB3
DB8
WB
VCC
DB4
DB5
DB6
DB7
FLB/RTB
RSB
TSTG
IOUT
Rating
Terminal Voltage with
Respect to GND
Storage Temperature
DC Output Current
Com'l & Ind'l
–0.5 to +7.0
Unit
V
–55 to +125
–50 to +50
°C
mA
NOTE:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause
permanent damage to the device. This is a stress rating only and functional operation
of the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect reliability.
RECOMMENDED DC OPERATING
CONDITIONS
Symbol
VCC
GND
VIH(1)
VIL(2)
TA
TA
3208 drw 02
Parameter
Supply Voltage
Supply Voltage
Input High Voltage
Input Low Voltage
Operating Temperature
Commercial
Operating Temperature
Industrial
Min.
4.5
0
2.0
—
0
Typ.
5.0
0
—
—
—
Max.
5.5
0
—
0.8
70
Unit
V
V
V
V
°C
–40
—
85
°C
NOTES:
1. For RT/RS/XI input, VIH = 2.6V (commercial).
2. 1.5V undershoots are allowed for 10ns once per cycle.
TSSOP (SO56-2, order code: PA)
TOP VIEW
DC ELECTRICAL CHARACTERISTICS
(Commercial: VCC = 5V ± 10%, TA = 0°C to +70°C; Industrial: VCC = 5V ± 10%, TA = –40°C to +85°C)
Symbol
ILI(2)
ILO(3)
VOH
VOL
ICC1(4,5)
ICC2(4,7)
IDT7280L
IDT7281L
IDT7282L
Commercial & Industrial(1)
tA = 12, 15 ns
Min.
Max.
–1
1
–10
10
2.4
—
—
0.4
—
125(6)
—
15
Parameter
Input Leakage Current (Any Input)
Output Leakage Current
Output Logic “1” Voltage
IOH = –2mA
Output Logic “0” Voltage
IOL = 8mA
Active Power Supply Current (both FIFOs)
Standby Current (R=W=RS=FL/RT=VIH)
NOTES:
1. Industrial temperature range product for the 15ns speed grade is available as a standard
device.
2. Measurements with 0.4 ≤ VIN ≤ VCC.
3. R ≥ VIH, 0.4 ≤ VOUT ≤ VCC.
4. Tested with outputs open (IOUT = 0).
5. Tested at f = 20 MHz.
6. Typical ICC1 = 2*[15 + 2*fS + 0.02*CL*fS] (in mA) with VCC = 5V, TA = 25oC, fS = WCLK
frequency = RCLK frequency (in MHz, using TTL levels), data switching at fS/2,
CL = capacitive load (in pF).
7. All Inputs = VCC - 0.2V or GND + 0.2V.
AC TEST CONDITIONS
Input Pulse Levels
Input Rise/Fall Times
Input Timing Reference Levels
Output Reference Levels
Output Load
Parameter
Input Capacitance
Output Capacitance
Condition
VIN = 0V
VOUT = 0V
TO
OUTPUT
PIN
Max.
8
8
GND to 3.0V
5ns
1.5V
1.5V
See Figure 1
5V
CAPACITANCE (TA = +25oC, f = 1.0 MHz)
Symbol
CIN
COUT
IDT7283L
IDT7284L
IDT7285lL
Commercial & Industrial(1)
tA = 12, 15 ns
Min.
Max.
–1
—
–10
10
2.4
—
—
0.4
—
150
—
15
Unit
pF
pF
680Ω
1.1K
30pF*
3208 drw 03
or equivalent circuit
Figure 1. Output Load
NOTE:
1. Characterized values, not currently tested.
* Includes scope and jig capacitances.
2
Unit
µA
µA
V
V
mA
mA
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
COMMERCIAL TEMPERATURE RANGE
AC ELECTRICAL CHARACTERISTICS(1)
(Commercial: VCC = 5V ± 10%, TA = 0°C to +70°C; Industrial: VCC = 5V ± 10%, TA = –40°C to +85°C)
Symbol
Commercial
IDT7280L12
IDT7281L12
IDT7282L12
IDT7283L12
IDT7284L12
IDT7285L12
Min.
Max.
Parameter
Commercial & Industrial(2)
IDT7280L15
IDT7281L15
IDT7282L15
IDT7283L15
IDT7284L15
IDT7285L15
Min.
Max.
Unit
tS
Shift Frequency
—
50
—
40
MHz
tRC
Read Cycle Time
20
—
25
—
ns
tA
Access Time
—
12
—
15
ns
tRR
Read Recovery Time
8
—
10
—
ns
tRPW
Read Pulse Width(3)
12
—
15
—
ns
tRLZ
Read Pulse Low to Data Bus at Low Z(4)
3
—
3
—
ns
(4,5)
tWLZ
Write Pulse High to Data Bus at Low Z
5
—
5
—
ns
tDV
Data Valid from Read Pulse High
5
—
5
—
ns
(4)
tRHZ
Read Pulse High to Data Bus at High Z
—
12
—
15
ns
tWC
Write Cycle Time
20
—
25
—
ns
tWPW
Write Pulse Width(3)
12
—
15
—
ns
tWR
Write Recovery Time
8
—
10
—
ns
tDS
Data Set-up Time
9
—
11
—
ns
tDH
Data Hold Time
0
—
0
—
ns
tRSC
Reset Cycle Time
20
—
25
—
ns
tRS
Reset Pulse Width(3)
12
—
15
—
ns
tRSS
Reset Set-up Time(4)
12
—
15
—
ns
tRSR
Reset Recovery Time
8
—
10
—
ns
tRTC
Retransmit Cycle Time
20
—
25
—
ns
tRT
Retransmit Pulse Width(3)
12
—
15
—
ns
tRTS
Retransmit Set-up Time(4)
12
—
15
—
ns
tRTR
Retransmit Recovery Time
8
—
10
—
ns
tEFL
Reset to Empty Flag Low
—
12
—
25
ns
tHFH,FFH
Reset to Half-Full and Full Flag High
—
17
—
25
ns
tRTF
Retransmit Low to Flags Valid
—
20
—
25
ns
tREF
Read Low to Empty Flag Low
—
12
—
15
ns
tRFF
Read High to Full Flag High
—
14
—
15
ns
tRPE
Read Pulse Width after EF High
12
—
15
—
ns
tWEF
Write High to Empty Flag High
—
12
—
15
ns
tWFF
Write Low to Full Flag Low
—
14
—
15
ns
tWHF
Write Low to Half-Full Flag Low
—
17
—
25
ns
tRHF
Read High to Half-Full Flag High
—
17
—
25
ns
tWPF
Write Pulse Width after FF High
12
—
15
—
ns
tXOL
Read/Write to XO Low
—
12
—
15
ns
tXOH
Read/Write to XO High
—
12
—
15
ns
tXI
XI Pulse Width(3)
12
—
15
—
ns
tXIR
XI Recovery Time
8
—
10
—
ns
tXIS
XI Set-up Time
8
—
10
—
ns
NOTES:
1. Timings referenced as in AC Test Conditions.
2. Industrial temperature range product for the 15ns speed grade is available as a standard device.
3. Pulse widths less than minimum value are not allowed.
4. Values guaranteed by design, not currently tested.
5. Only applies to read data flow-through mode.
3
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
COMMERCIAL TEMPERATURE RANGE
Device Mode, this pin acts as the retransmit input. The Single Device Mode is
initiated by grounding the Expansion In (XI).
These devices can be made to retransmit data when the Retransmit Enable
control (RT) input is pulsed LOW. A retransmit operation will set the internal read
pointer to the first location and will not affect the write pointer. Read Enable (R)
and Write Enable (W) must be in the HIGH state during retransmit. This feature
is useful when less than 256/512/1,024/2,048/4,096/8,192 writes are performed between resets. The retransmit feature is not compatible with the Depth
Expansion Mode and will affect the Half-Full Flag (HF), depending on the
relative locations of the read and write pointers.
SIGNAL DESCRIPTIONS
INPUTS:
DATA IN (D0 – D8)
Data inputs for 9-bit wide data.
CONTROLS:
RESET (RS)
Reset is accomplished whenever the Reset (RS) input is taken to a LOW state.
During reset, both internal read and write pointers are set to the first location.
A reset is required after power up before a write operation can take place. Both
the Read Enable (R) and Write Enable (W) inputs must be in the HIGH
state during the window shown in Figure 2, (i.e., tRSS before the rising
edge of RS) and should not change until tRSR after the rising edge of
RS. Half-Full Flag (HF) will be reset to HIGH after Reset (RS).
EXPANSION IN (XI)
This input is a dual-purpose pin. Expansion In (XI) is grounded to indicate
an operation in the single device mode. Expansion In (XI) is connected to
Expansion Out (XO) of the previous device in the Depth Expansion or Daisy
Chain Mode.
WRITE ENABLE (W)
A write cycle is initiated on the falling edge of this input if the Full Flag (FF)
is not set. Data set-up and hold times must be adhered to with respect to the rising
edge of the Write Enable (W). Data is stored in the RAM array sequentially and
independently of any on-going read operation.
After half of the memory is filled and at the falling edge of the next write
operation, the Half-Full Flag (HF) will be set to LOW and will remain set until the
difference between the write pointer and read pointer is less than or equal to
one half of the total memory of the device. The Half-Full Flag (HF) is then reset
by the rising edge of the read operation.
To prevent data overflow, the Full Flag (FF) will go LOW, inhibiting further
write operations. Upon the completion of a valid read operation, the Full Flag
(FF) will go HIGH after tRFF, allowing a valid write to begin. When the FIFO is
full, the internal write pointer is blocked from W, so external changes in W will
not affect the FIFO when it is full.
OUTPUTS:
FULL FLAG (FF)
The Full Flag (FF) will go LOW, inhibiting further write operation, when the
write pointer is one location less than the read pointer, indicating that the
device is full. If the read pointer is not moved after Reset (RS), the Full-Flag (FF)
will go LOW after 256 writes for IDT7280, 512 writes for the IDT7281, 1,024
writes for the IDT7282, 2,048 writes for the IDT7283, 4,096 writes for the
IDT7284 and 8,192 writes for the IDT7285.
EMPTY FLAG (EF)
The Empty Flag (EF) will go LOW, inhibiting further read operations, when
the read pointer is equal to the write pointer, indicating that the device is
empty.
EXPANSION OUT/HALF-FULL FLAG (XO/HF)
This is a dual-purpose output. In the single device mode, when Expansion In (XI) is grounded, this output acts as an indication of a half-full memory.
After half of the memory is filled and at the falling edge of the next write
operation, the Half-Full Flag (HF) will be set LOW and will remain set until the
difference between the write pointer and read pointer is less than or equal
to one half of the total memory of the device. The Half-Full Flag (HF) is then reset
by using rising edge of the read operation.
In the Depth Expansion Mode, Expansion In (XI) is connected to Expansion
Out (XO) of the previous device. This output acts as a signal to the next device
in the Daisy Chain by providing a pulse to the next device when the previous
device reaches the last location of memory.
READ ENABLE (R)
A read cycle is initiated on the falling edge of the Read Enable (R) provided
the Empty Flag (EF) is not set. The data is accessed on a First-In/First-Out basis,
independent of any ongoing write operations. After Read Enable (R) goes
HIGH, the Data Outputs (Q0 – Q8) will return to a high impedance condition until
the next Read operation. When all data has been read from the FIFO, the Empty
Flag (EF) will go LOW, allowing the “final” read cycle but inhibiting further read
operations with the data outputs remaining in a high impedance state. Once a
valid write operation has been accomplished, the Empty Flag (EF) will go HIGH
after tWEF and a valid Read can then begin. When the FIFO is empty, the internal
read pointer is blocked from R so external changes in R will not affect the FIFO
when it is empty.
DATA OUTPUTS (Q0 – Q8)
Data outputs for 9-bit wide data. This data is in a high impedance
condition whenever Read (R) is in a HIGH state.
FIRST LOAD/RETRANSMIT (FL/RT)
This is a dual-purpose input. In the Depth Expansion Mode, this pin is
grounded to indicate that it is the first loaded (see Operating Modes). In the Single
4
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
COMMERCIAL TEMPERATURE RANGE
tRSC
tRS
RS
tRSS
tRSR
W
tRSS
R
tEFL
EF
tHFH , tFFH
HF, FF
3208 drw 04
NOTES:
1. EF, FF, HF may change status during Reset, but flags will be valid at tRSC.
2. W and R = VIH around the rising edge of RS.
Figure 2. Reset
t RC
t RPW
tRR
tA
tA
R
t DV
t RLZ
Q0-Q8
t RHZ
DATA OUT VALID
t WPW
t WC
DATA OUT VALID
t WR
W
t DS
D0-D8
t DH
DATA IN VALID
DATA IN VALID
3208 drw 05
Figure 3. Asynchronous Write and Read Operation
LAST WRITE
IGNORED
WRITE
FIRST READ
ADDITIONAL
READS
FIRST
WRITE
R
W
tWFF
t RFF
FF
3208 drw 06
Figure 4. Full Flag From Last Write to First Read
5
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
LAST READ
IGNORED
READ
COMMERCIAL TEMPERATURE RANGE
FIRST WRITE
ADDITIONAL
WRITES
FIRST
READ
W
R
t WEF
t REF
EF
tA
DATA OUT
VALID
VALID
3208 drw 07
Figure 5. Empty Flag From Last Read to First Write
tRTC
tRT
RT
tRTS
t RTR
W,R
t RTF
HF, EF, FF
FLAG VALID
3208 drw 08
Figure 6. Retransmit
W
tWEF
EF
tRPE
R
3208 drw 09
Figure 7. Minimum Timing for an Empty Flag Coincident Read Pulse
R
t RFF
FF
t WPF
W
3208 drw 10
Figure 8. Minimum Timing for a Full Flag Coincident Write Pulse
6
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
COMMERCIAL TEMPERATURE RANGE
W
t RHF
R
t WHF
HF
HALF-FULL OR LESS
HALF-FULL OR LESS
MORE THAN HALF-FULL
3208 drw 11
Figure 9. Half-Full Flag Timing
WRITE TO
LAST PHYSICAL
LOCATION
W
READ FROM
LAST PHYSICAL
LOCATION
R
tXOL
tXOH
tXOH
tXOL
3208 drw 12
XO
Figure 10. Expansion Out
t XI
tXIR
XI
t XIS
W
WRITE TO
FIRST PHYSICAL
LOCATION
tXIS
R
READ FROM
FIRST PHYSICAL
LOCATION
3208 drw 13
Figure 11. Expansion In
14 demonstrates a four-FIFO Depth Expansion using two IDT7280/7281/
7282/7283/7284/7285s. Any depth can be attained by adding additional
IDT7280/7281/7282/7283/7284/7285s. These FIFOs operate in the Depth
Expansion mode when the following conditions are met:
OPERATING MODES:
Care must be taken to assure that the appropriate flag is monitored by
each system (i.e. FF is monitored on the device where Wis used; EF is monitored
on the device where R is used).
1. The first FIFO must be designated by grounding the First Load (FL) control
input.
2. All other FIFOs must have FL in the HIGH state.
3. The Expansion Out (XO) pin of each device must be tied to the Expansion
In (XI) pin of the next device. See Figure 14.
4. External logic is needed to generate a composite Full Flag (FF) and Empty
Flag (EF). This requires the ORing of all EFs and ORing of all FFs (i.e. all
must be set to generate the correct composite FF or EF). See Figure 14.
5. The Retransmit (RT) function and Half-Full Flag (HF) are not available in
the Depth Expansion Mode.
SINGLE DEVICE MODE
A single IDT7280/7281/7282/7283/7284/7285 may be used when the
application requirements are for 256/512/1,024/2,048/4,096/8,192 words or
less. These FIFOs are in a Single Device Configuration when the Expansion
In (XI) control input is grounded (see Figure 12).
DEPTH EXPANSION
These devices can easily be adapted to applications when the requirements are for greater than 256/512/1,024/2,048/4,096/8,192 words. Figure
7
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
USAGE MODES:
the FIFO permits a reading of a single word after writing one word of data into
an empty FIFO. The data is enabled on the bus in (tWEF + tA) ns after the rising
edge of W, called the first write edge, and it remains on the bus until the R line
is raised from LOW-to-HIGH, after which the bus would go into a three-state
mode after tRHZ ns. The EF line would have a pulse showing temporary
deassertion and then would be asserted.
In the write flow-through mode (Figure 18), the FIFO permits the writing
of a single word of data immediately after reading one word of data from a
full FIFO. The R line causes the FF to be deasserted but the W line being LOW
causes it to be asserted again in anticipation of a new data word. On the rising
edge of W, the new word is loaded in the FIFO. The W line must be toggled when
FF is not asserted to write new data in the FIFO and to increment the write pointer.
WIDTH EXPANSION
Word width may be increased simply by connecting the corresponding input
control signals of multiple FIFOs. Status flags (EF, FF and HF) can be detected
from any one FIFO. Figure 13 demonstrates an 18-bit word width by using the
two FIFOs contained in the IDT7280/7281/7282/7283/7284/7285s. Any word
width can be attained by adding FIFOs (Figure 13).
BIDIRECTIONAL OPERATION
Applications which require data buffering between two systems (each
system capable of Read and Write operations) can be achieved by pairing
IDT7280/7281/7282/7283/7384/7285s as shown in Figure 16. Both Depth
Expansion and Width Expansion may be used in this mode.
COMPOUND EXPANSION
The two expansion techniques described above can be applied together
in a straightforward manner to achieve large FIFO arrays (see Figure 15).
DATA FLOW-THROUGH
Two types of flow-through modes are permitted, a read flow-through
and write flow-through mode. For the read flow-through mode (Figure 17),
(HALF-FULL FLAG)
WRITE (W)
(HF)
FIFO
A or B
IDT
7280
7281
7282
7283
7284
7285
9
DATA IN (D)
FULL FLAG (FF)
RESET (RS)
COMMERCIAL TEMPERATURE RANGE
READ (R)
9
DATA OUT (Q)
EMPTY FLAG (EF)
RETRANSMIT (RT)
3208 drw 14
EXPANSION IN (XI)
Figure 12. Block Diagram of One 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9, 8,192 x 9 FIFO Used in Single Device Mode
9
18
DATA
IN
(D)
HFA
HFB
FIFO A
FIFO B
9
WRITE (W)
READ (R)
EMPTY FLAG (EFB)
FULL FLAG (FFA)
RESET (RS)
RETRANSMIT (RT)
9
XIA
7280/7281/7282/
9 7283/7284/7285
XIB
18
DATA
OUT (Q)
3208 drw 15
Figure 13. Block Diagram of 256 x 18, 512 x 18, 1,024 x 18, 2,048 x 18, 4,096 x 18, 8,192 x 18 FIFO Memory Used in Width Expansion Mode
8
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
COMMERCIAL TEMPERATURE RANGE
TABLE 1 — RESET AND RETRANSMIT
Single Device Configuration/Width Expansion Mode
RS
Inputs
RT
XI
Reset
Retransmit
0
1
X
0
0
0
Location Zero
Location Zero
Location Zero
Unchanged
0
X
1
X
1
X
Read/Write
1
1
0
Increment(1)
Increment(1)
X
X
X
Mode
Read Pointer
Internal Status
Write Pointer
EF
Outputs
FF
HF
NOTE:
1. Pointer will increment if flag is High.
TABLE 2 — RESET AND FIRST LOAD TRUTH TABLE
Depth Expansion/Compound Expansion Mode
Mode
Reset First Device
Reset All Other Devices
Read/Write
RS
Inputs
FL
XI
Read Pointer
0
0
1
0
1
X
(1)
(1)
(1)
Location Zero
Location Zero
X
Internal Status
Write Pointer
Location Zero
Location Zero
X
Outputs
EF
FF
0
0
X
1
1
X
NOTE:
1. XI is connected to XO of previous device. See Figure 14. RS = Reset Input, FL/RT = First Load/Retransmit, EF = Empty Flag Output, FF = Full Flag Output,
XI = Expansion Input, HF = Half-Full Flag Output
XOA
EFA
FFA
FIFO A
FLA
XIA
7280/7281/
7282/7283/
7284/7285
XOB
W
D
9
9
R
EFB
FFB
FIFO B
9
FLB
Q
V CC
XIB
XOA
FFA
FULL
EFA
EMPTY
FIFO A
9
FLA
7280/7281/
7282/7283/
7284/7285
FFB
9
XIA
XOB
EFB
FIFO B
RSA
FLB
XIB
3208 drw 16
Figure 14. Block Diagram of 1,024 x 9, 2,048 x 9, 4,096 x 9, 8,192 x 9, 16,384 x 9, 32,768 x 9 FIFO Memory (Depth Expansion)
9
10
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
R, W, RS
COMMERCIAL TEMPERATURE RANGE
Q0-Q8
Q9-Q17
Q(N-8)-QN
Q0-Q8
Q9-Q17
Q(N-8)-QN
IDT7280/7281/
7282/7283/
7284/7285
DEPTH
EXPANSION
BLOCK
IDT7280/7281/
7282/7283/
7284/7285
DEPTH
EXPANSION
BLOCK
D0-D8
IDT7280/7281/
7282/7283/
7284/7285
DEPTH
EXPANSION
BLOCK
D(N-8)-DN
D9-D17
D0-DN
D18-DN
D9-DN
D(N-8)-DN
3208 drw 17
NOTES:
1. For depth expansion block see section on Depth Expansion and Figure 14.
2. For Flag detection see section on Width Expansion and Figure 13.
Figure 15. Compound FIFO Expansion
WA
FFA
D A0-8
SIDE 1
FIFO
IDTA
7201A
QA0-8
IDT
7280
7281
7282
7283
7284
7285
QB0-8
RB
HF B
EFB
RA
EFA
HFA
SIDE 2
D B0-8
FIFO B
WB
FFB
Figure 16. Bidirectional FIFO Mode
10
3208 drw 18
IDT7280/7281/7282/7283/7284/7285 5V ASYNCHRONOUS FIFO
DUAL 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9
COMMERCIAL TEMPERATURE RANGE
DATA IN
W
t RPE
R
EF
t WLZ
t WEF
tA
t REF
DATA OUT
DATA
OUT VALID
3208 drw 19
Figure 17. Read Data Flow-Through Mode
R
t WPF
W
tRFF
FF
tDH
t WFF
DATA
DATA IN
tA
DATA OUT
IN
VALID
t DS
DATA
OUT
VALID
3208 drw 20
Figure 18. Write Data Flow-Through Mode
11
ORDERING INFORMATION
IDT
XXXX
X
XXX
X
X
Device Type
Power
Speed
Package
Process/
Temperature
Range
Blank
I(1)
Commercial (0°C to +70°C)
Industrial (-40°C to +85°C)
PA
Thin Shrink SOIC (TSSOP, SO56-2)
12
15
Commercial Only
Commercial and Industrial
L
Low Power
7280
7281
7282
7283
7284
7285
256 x 9  CMOS Dual Asynchronous FIFO
512 x 9  CMOS Dual Asynchronous FIFO
1,024 x 9  CMOS Dual Asynchronous FIFO
2,048 x 9  CMOS Dual Asynchronous FIFO
4,096 x 9  CMOS Dual Asynchronous FIFO
8,192 x 9  CMOS Dual Asynchronous FIFO
NOTE:
1. Industrial temperature range product for the 15ns speed grade is available as a standard device.
Access Time (tA) Speed
in Nanoseconds
3208 drw 21
DATASHEET DOCUMENT HISTORY
07/13/2001
pgs. 2, 3 and 12.
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12
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