IDT IDT72V821L20TF 3.3 volt dual cmos syncfifoâ ¢ Datasheet

IDT72V801
IDT72V811
IDT72V821
IDT72V831
IDT72V841
IDT72V851
3.3 VOLT DUAL CMOS SyncFIFO™
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:
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Each of the two FIFOs (designated FIFO A and FIFO B) contained in the
IDT72V801/72V811/72V821/72V831/72V841/72V851 has a 9-bit input data
port (DA0 - DA8, DB0 - DB8) and a 9-bit output data port (QA0 - QA8,
QB0 - QB8). Each input port is controlled by a free-running clock (WCLKA,
WCLKB), and two Write Enable pins (WENA1, WENA2, WENB1, WENB2).
Data is written into each of the two arrays on every rising clock edge of the Write
Clock (WCLKA, WCLKB) when the appropriate Write Enable pins are
asserted.
The output port of each FIFO bank is controlled by its associated clock pin
(RCLKA, RCLKB) and two Read Enable pins (RENA1, RENA2, RENB1,
RENB2). The Read Clock can be tied to the Write Clock for single clock operation
or the two clocks can run asynchronous of one another for dual clock operation.
An Output Enable pin (OEA, OEB) is provided on the read port of each FIFO
for three-state output control.
Each of the two FIFOs has two fixed flags, Empty (EFA, EFB) and Full (FFA,
FFB). Two programmable flags, Almost-Empty (PAEA, PAEB) and Almost-Full
(PAFA, PAFB), are provided for each FIFO bank to improve memory utilization.
If not programmed, the programmable flags default to Empty+7 for PAEA and
PAEB, and Full-7 for PAFA and PAFB.
The IDT72V801/72V811/72V821/72V831/72V841/72V851 architecture
lends itself to many flexible configurations such as:
• 2-level priority data buffering
• Bidirectional operation
• Width expansion
• Depth expansion
This FIFO is fabricated using IDT's high-performance submicron CMOS
technology.
The IDT72V801 is equivalent to two IDT72V201 256 x 9 FIFOs
The IDT72V811 is equivalent to two IDT72V211 512 x 9 FIFOs
The IDT72V821 is equivalent to two IDT72V221 1,024 x 9 FIFOs
The IDT72V831 is equivalent to two IDT72V231 2,048 x 9 FIFOs
The IDT72V841 is equivalent to two IDT72V241 4,096 x 9 FIFOs
The IDT72V851 is equivalent to two IDT72V251 8,192 x 9 FIFOs
Offers optimal combination of large capacity, high speed,
design flexibility and small footprint
Ideal for prioritization, bidirectional, and width expansion
applications
10 ns read/write cycle time
5V input tolerant
Separate control lines and data lines for each FIFO
Separate Empty, Full, programmable Almost-Empty and
Almost-Full flags for each FIFO
Enable puts output data lines in high-impedance state
Space-saving 64-pin plastic Thin Quad Flat Pack (TQFP/
STQFP)
Industrial temperature range (–40°°C to +85°°C) is available
DESCRIPTION:
The IDT72V801/72V811/72V821/72V831/72V841/72V851/72V851 are
dual synchronous (clocked) FIFOs. The device is functionally equivalent to
two IDT72V201/72V211/72V221/72V231/72V241/72V251 FIFOs in a single
package with all associated control, data, and flag lines assigned to separate
pins.
FUNCTIONAL BLOCK DIAGRAM
WCLKA
WENA1
WENA2
INPUT REGISTER
WRITE CONTROL
LOGIC
WRITE POINTER
WCLKB
EFA
PAEA
WENB1
PAFA
WENB2
FFA
DA0 - DA8
RAM ARRAY
256 x 9, 512 x 9,
1,024 x 9, 2,048 x 9,
4,096 x 9, 8,192 x 9
DB0 - DB8
LDA
OFFSET REGISTER
INPUT REGISTER
FLAG
LOGIC
WRITE CONTROL
LOGIC
READ POINTER
WRITE POINTER
OFFSET REGISTER
FLAG
LOGIC
RAM ARRAY
256 x 9, 512 x 9,
1,024 x 9, 2,048 x 9,
4,096 x 9, 8,192 x 9
READ CONTROL
LOGIC
EFB
PAEB
PAFB
FFB
READ POINTER
READ CONTROL
LOGIC
OUTPUT REGISTER
OUTPUT REGISTER
RESET LOGIC
RSA
LDB
RESET LOGIC
OEA
QA0 - QA8
RSB
RCLKA
RENA1
RENA2
OEB
QB0 - QB8
RCLKB
RENB1
RENB2
4093 drw 01
The IDT logo is a registered trademark and the SyncFIFO is a trademark of Integrated Device Technology, Inc.
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
APRIL 2001
1
 2001 Integrated Device Technology, Inc.
DSC-4093/1
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
QA0
FFA
EFA
OEA
RENA2
RCLKA
RENA1
GND
QB8
QB7
QB6
QB5
QB4
QB3
QB2
QB1
PIN CONFIGURATION
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
DA5
DA4
DA3
DA2
DA1
DA0
PAFA
PAEA
WENB2/LDB
WCLKB
WENB1
RSB
DB8
DB7
DB6
DB5
QA1
QA2
QA3
QA4
QA5
QA6
QA7
QA8
VCC
WENA2/LDA
WCLKA
WENA1
RSA
DA8
DA7
DA6
TQFP (PN64-1, order code: PF)
STQFP (PP64-1, order code: TF)
TOP VIEW
2
QB0
FFB
EFB
OEB
RENB2
RCLKB
RENB1
GND
Vcc
PAEB
PAFB
DB0
DB1
DB2
DB3
DB4
4093 drw 02
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
PIN DESCRIPTIONS
The IDT72V801/72V811/72V821/72V831/72V841/72V851's two FIFOs,
referred to as FIFO A and FIFO B, are identical in every respect. The following
Symbol
Name
I/O
description defines the input and output signals for FIFO A. The corresponding
signal names for FIFO B are provided in parentheses.
Description
DA0-DA8
A Data Inputs
I
9-bit data inputs to RAM array A.
DB0-DB8
B Data Inputs
I
9-bit data inputs to RAM array B.
RSA, RSB
Reset
I
When RSA (RSB) is set LOW, the associated internal read and write pointers of array A (B) are set to the first
location; FFA (FFB) and PAFA (PAFB) go HIGH, and PAEA (PAEB) and EFA (EFB) go LOW. After powerup, a reset of both FIFOs A and B is required before an initial WRITE.
WCLKA
WCLKB
Write Clock
I
Data is written into the FIFO A (B) on a LOW-to-HIGH transition of WCLKA (WCLKB) when the write enable(s)
are asserted.
WENA1
WENB1
Write Enable 1
I
If FIFO A (B) is configured to have programmable flags, WENA1 (WENB1) is the only write enable pin that can be
used. When WENA1 (WENB1) is LOW, data A (B) is written into the FIFO on every LOW-to-HIGH transition
WCLKA (WCLKB). If the FIFO is configured to have two write enables, WENA1 (WENB1) must be LOW and
WENA2 (WENB2) must be HIGH to write data into the FIFO. Data will not be written into the FIFO if FFA (FFB) is
LOW.
WENA2/LDA
WENB2/LDB
Write Enable 2/
Load
I
FIFO A (B) is configured at reset to have either two write enables or programmable flags. If LDA (LDB) is HIGH at
reset, this pin operates as a second Write Enable. If WENA2/LDA (WENB2/LDB) is LOW at reset this pin operates
as a control to load and read the programmable flag offsets for its respective array. If the FIFO is configured to have
two write enables, WENA1 (WENB1) must be LOW and WENA2 (WENB2) must be HIGH to write data into FIFO
A (B). Data will not be written into FIFO A (B) if FFA (FFB) is LOW. If the FIFO is configured to have programmable
flags, LDA (LDB) is held LOW to write or read the programmable flag offsets.
QA0-QA8
A Data Outputs
O 9-bit data outputs from RAM array A.
QB0-QB8
B Data Outputs
O 9-bit data outputs from RAM array B.
RCLKA
RCLKB
Read Clock
I
Data is read from FIFO A (B) on a LOW-to-HIGH transition of RCLKA (RCLKB) when RENA1(RENB1) and
RENA2 (RENB2) are asserted.
RENA1
RENB1
Read Enable 1
I
When RENA1 (RENB1) and RENA2 (RENB2) are LOW, data is read from FIFO A (B) on every LOW-to-HIGH
transition of RCLKA (RCLKB). Data will not be read from Array A (B) if EFA (EFB) is LOW.
RENA2
RENB2
Read Enable 2
I
When RENA1 (RENB1) and RENA2 (RENB2) are LOW, data is read from the FIFO A (B) on every LOW-toHIGH transition of RCLKA (RCLKB). Data will not be read from array A (B) if the EFA (EFB) is LOW.
OEA
Output Enable
I
When OEA (OEB) is LOW, outputs DA0-DA8 (DB0-DB8) are active. If OEA (OEB) is HIGH, the OEB outputs DA0DA8 (DB0-DB8) will be in a high-impedance state.
EFA
EFB
Empty Flag
O When EFA (EFB) is LOW, FIFO A (B) is empty and further data reads from the output are inhibited. When EFA
(EFB) is HIGH, FIFO A (B) is not empty. EFA (EFB) is synchronized to RCLKA (RCLKB).
PAEA
PAEB
Programmable
Almost-Empty Flag
O When PAEA (PAEB) is LOW, FIFO A (B) is Almost-Empty based on the offset programmed into the appropriate
offset register. The default offset at reset is Empty+7. PAEA (PAEB) is synchronized to RCLKA (RCLKB).
PAFA
PAFB
Programmable
Almost-Full Flag
O When PAFA (PAFB) is LOW, FIFO A (B) is Almost-Full based on the offset programmed into the appropriate offset
register. The default offset at reset is Full-7. PAFA (PAFB) is synchronized to WCLKA (WCLKB).
FFA
FFB
Full Flag
O When FFA (FFB) is LOW, FIFO A (B) is full and further data writes into the input are inhibited. When FFA (FFB) is
HIGH, FIFO A (B) is not full. FFA (FFB) is synchronized to WCLKA (WCLKB).
V CC
Power
+3.3V power supply pin.
GND
Ground
0V ground pin.
3
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
RECOMMENDED OPERATING
CONDITIONS
ABSOLUTE MAXIMUM RATINGS
Symbol
VTERM
TSTG
IOUT
Rating
Terminal Voltage with
Respect to GND
Storage Temperature
DC Output Current
Commercial
Unit
–0.5 to +5
V
–55 to +125
–50 to +50
°C
mA
Symbol
Min
Typ.
Max
Unit
Supply Voltage(Com’l & Ind’l)
3.0
3.3
3.6
V
GND
Supply Voltage(Com’l & Ind’l)
0
0
—
V
VIH
Input High Voltage
(Com’l & Ind’l)
2.0
—
5.0
V
Input Low Voltage
(Com’l & Ind’l)
—
—
0.8
V
VCC
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 the specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect reliability.
VIL
Parameter
TA
Operating Temperature
Commercial
0
—
70
°C
TA
Operating Temperature
Industrial
-40

85
°C
DC ELECTRICAL CHARACTERISTICS
(Commercial: VCC = 3.3V ± 0.3V, TA = 0°C to +70°C; Industrial :VCC = 3.3V ± 0.3V, TA = -40°C to +85°C)
Min.
IDT72V801
IDT72V811
IDT72V821
IDT72V831
IDT72V841
IDT72V851
Commercial and Industrial (1)
tCLK = 10, 15, 20 ns
Typ.
Max.
Unit
Input Leakage Current (Any Input)
–1
—
–1
µA
Output Leakage Current
–10
—
10
µA
VOH
Output Logic “1” Voltage, IOH = –2 mA
2.4
—
—
V
VOL
Output Logic “0” Voltage, IOL = 8 mA
—
—
0.4
V
Active Power Supply Current (both FIFOs)
—
—
40
mA
Standby Current
—
—
10
mA
Symbol
ILI
(2)
ILO
(3)
ICC1(4,5,6)
(3,7)
ICC2
Parameter
NOTES:
1. Industrial temperature range product for the 15ns speed grade is available as a standard device.
2. Measurements with 0.4 ≤ V IN ≤ VCC.
3. OEA, OEB ≥ VIH, 0.4 ≤ V OUT ≤ VCC.
4. Tested with outputs disabled (IOUT = 0).
5. RCLK and WCLK toggle at 20 MHz and data inputs switch at 10 MHz.
6. Typical ICC1 = 2[0.17 + 0.48*fS + 0.02*CL*fS] (in mA).
These equations are valid under the following conditions:
V CC = 3.3V, T A = 25°C, fS = WCLK frequency = RCLK frequency (in MHz, using TTL levels), data switching at fS/2, CL = capacitive load (in pF).
7. All Inputs = V CC - 0.2V or GND + 0.2V, except RCLK and WCLK, which toggle at 20 MHz.
CAPACITANCE (TA = +25°C, f = 1.0MHz)
Symbol
(2)
CIN
COUT
Parameter
Input Capacitance
(1,2)
Output Capacitance
Conditions
Max.
Unit
VIN = 0V
10
pF
VOUT = 0V
10
pF
NOTE:
1. With output deselected (OEA, OEB ≥ VIH).
2. Characterized values, not currently tested.
4
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
AC ELECTRICAL CHARACTERISTICS(1)
(Commercial: VCC = 3.3V ± 0.3V, TA = 0°C to +70°C; Industrial: VCC = 3.3V± 0.3V, TA = -40°C to +85°C)
Symbol
Parameter
Commercial
Com’l & Ind’l
Commercial
IDT72V801L10
IDT72V811L10
IDT72V821L10
IDT72V831L10
IDT72V841L10
IDT72V851L10
IDT72V801L15
IDT72V811L15
IDT72V821L15
IDT72V831L15
IDT72V841L15
IDT72V851L15
IDT72V801L20
IDT72V811L20
IDT72V821L20
IDT72V831L20
IDT72V841L20
IDT72V851L20
Min.
Max.
Min.
Max.
Min.
—
100
—
66.7
—
50
MHz
Max.
Unit
fS
Clock Cycle Frequency
tA
Data Access Time
2
6.5
2
10
2
12
ns
tCLK
Clock Cycle Time
10
—
15(1)
—
20
—
ns
tCLKH
Clock High Time
4.5
—
6
—
8
—
ns
tCLKL
Clock Low Time
4.5
—
6
—
8
—
ns
tDS
Data Set-up Time
3
—
4
—
5
—
ns
tDH
Data Hold Time
0.5
—
1
—
1
—
ns
tENS
Enable Set-up Time
3
—
4
—
5
—
ns
tENH
Enable Hold Time
0.5
—
1
—
1
—
ns
tRS
Reset Pulse Width(2)
10
—
15
—
20
—
ns
tRSS
Reset Set-up Time
8
—
10
—
12
—
ns
tRSR
Reset Recovery Time
8
—
10
—
12
—
ns
tRSF
Reset to Flag Time and Output Time
—
10
—
15
—
20
ns
tOLZ
Output Enable to Output in Low-Z(3)
0
—
0
—
0
—
ns
tOE
Output Enable to Output Valid
3
6
3
8
3
10
ns
tOHZ
Output Enable to Output in High-Z(3)
3
6
3
8
3
10
ns
tWFF
Write Clock to Full Flag
—
6.5
—
10
—
12
ns
tREF
Read Clock to Empty Flag
—
6.5
—
10
—
12
ns
tPAF
Write Clock to Programmable Almost-Full Flag
—
6.5
—
10
—
12
ns
tPAE
Read Clock to Programmable Almost-Empty Flag
—
6.5
—
10
—
12
ns
tSKEW1
Skew Time Between Read Clock and Write Clock
for Empty Flag and Full Flag
5
—
6
—
8
—
ns
tSKEW2
Skew Time Between Read Clock and Write Clock for
Programmable Almost-Empty Flag and Programmable
Almost-Full Flag
14
—
18
—
20
—
ns
NOTES:
1. Industrial temperature range product for the 15ns speed grade is available as a standard device.
2. Pulse widths less than minimum values are not allowed.
3. Values guaranteed by design, not currently tested.
3.3V
330Ω
D.U.T.
AC TEST CONDITIONS
In Pulse Levels
Input Rise/Fall Times
3ns
Input Timing Reference Levels
1.5V
Output Reference Levels
1.5V
Output Load
510Ω
GND to 3.0V
30pF*
4093 drw 03
or equivalent circuit
Figure 1. Output Load
See Figure 1
*Includes jig and scope capacitances.
5
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
SIGNAL DESCRIPTIONS
When either of the two Read Enable, RENA1, RENA2 (RENB1, RENB2)
associated with FIFO A (B) is HIGH, the output register holds the previous data
and no new data is allowed to be loaded into the register.
When all the data has been read from FIFO A (B), the Empty Flag, EFA
(EFB) will go LOW, inhibiting further read operations. Once a valid write
operation has been accomplished, EFA (EFB) will go HIGH after tREF and a
valid read can begin. The Read Enables, RENA1, RENA2 (RENB1, RENB2)
are ignored when FIFO A (B) is empty.
FIFO A and FIFO B are identical in every respect. The following description
explains the interaction of input and output signals for FIFO A. The corresponding signal names for FIFO B are provided in parentheses.
INPUTS:
Data In (DA0 – DA8, DB0 – DB8) — DA0 - DA8 are the nine data inputs
for memory array A. DB0 - DB8 are the nine data inputs for memory array B.
Output Enable (OEA, OEB) — When Output Enable, OEA (OEB) is
enabled (LOW), the parallel output buffers of FIFO A (B) receive data from their
respective output register. When Output Enable, OEA (OEB) is disabled
(HIGH), the QA (QB) output data bus is in a high-impedance state.
CONTROLS:
Reset (RSA, RSB) — Reset of FIFO A (B) is accomplished whenever RSA
(RSB) input is taken to a LOW state. During reset, the internal read and write
pointers associated with the FIFO are set to the first location. A reset is required
after power-up before a write operation can take place. The Full Flag, FFA
(FFB) and Programmable Almost-Full Flag, PAFA (PAFB) will be reset to HIGH
after tRSF. The Empty Flag, EFA (EFB) and Programmable Almost-Empty Flag,
PAEA (PAEB) will be reset to LOW after tRSF. During reset, the output register
is initialized to all zeros and the offset registers are initialized to their default
values.
Write Enable 2/Load (WENA2/LDA, WENB2/LDB) — This is a dualpurpose pin. FIFO A (B) is configured at Reset to have programmable flags
or to have two write enables, which allows depth expansion. If WENA2/LDA
(WENB2/LDB) is set HIGH at Reset, RSA = LOW (RSB = LOW), this pin operates
as a second Write Enable pin.
If FIFO A (B) is configured to have two write enables, when Write Enable
1, WENA1 (WENB1) is LOW and WENA2/LDA (WENB2/LDB) is HIGH, data can
be loaded into the input register and RAM array on the LOW-to-HIGH transition
of every Write Clock, WCLKA (WCLKB). Data is stored in the array sequentially
and independently of any on-going read operation.
In this configuration, when WENA1 (WENB1) is HIGH and/or WENA2/LDA
(WENB2/LDB) is LOW, the input register of Array A holds the previous data
and no new data is allowed to be loaded into the register.
To prevent data overflow, the Full Flag, FFA (FFB) will go LOW, inhibiting
further write operations. Upon the completion of a valid read cycle, FFA (FFB)
will go HIGH after tWFF, allowing a valid write to begin. WENA1, (WENB1) and
WENA2/LDA (WENB2/LDB) are ignored when the FIFO is full.
FIFO A (B) is configured to have programmable flags when the WENA2/
LDA (WENB2/LDB) is set LOW at Reset, RSA = LOW (RSB = LOW). Each FIFO
Write Clock (WCLKA, WCLKB) — A write cycle to Array A (B) is initiated
on the LOW-to-HIGH transition of WCLKA (WCLKB). Data set-up and hold
times must be met with respect to the LOW-to-HIGH transition of WCLKA
(WCLKB). The Full Flag, FFA (FFB) and Programmable Almost-Full Flag,
PAFA (PAFB) are synchronized with respect to the LOW-to-HIGH transition of
the Write Clock, WCLKA (WCLKB).
The Write and Read clock can be asynchronous or coincident.
Write Enable 1 (WENA1, WENB1) — If FIFO A (B) is configured for
programmable flags, WENA1 (WENB1) is the only enable control pin. In this
configuration, when WENA1 (WENB1) is LOW, data can be loaded into the input
register of RAM Array A (B) on the LOW-to-HIGH transition of every Write
Clock, WCLKA (WCLKB). Data is stored in Array A (B) sequentially and
independently of any on-going read operation.
In this configuration, when WENA1 (WENB1) is HIGH, the input register
holds the previous data and no new data is allowed to be loaded into the
register.
If the FIFO is configured to have two write enables, which allows for depth
expansion. See Write Enable 2 paragraph below for operation in this
configuration.
To prevent data overflow, FFA (FFB) will go LOW, inhibiting further write
operations. Upon the completion of a valid read cycle, the FFA (FFB) will go
HIGH after tWFF, allowing a valid write to begin. WENA1 (WENB1) is ignored
when FIFO A (B) is full.
LDA
WENA1
WCLKA
OPERATION ON FIFO A
LDB
WENB1
WCLKB
OPERATION ON FIFO B
0
0
Empty Offset (LSB)
Empty Offset (MSB)
Full Offset (LSB)
Full Offset (MSB)
Read Clock (RCLKA, RCLKB) — Data can be read from Array A (B)
on the LOW-to-HIGH transition of RCLKA (RCLKB). The Empty Flag, EFA
(EFB) and Programmable Almost-Empty Flag, PAEA (PAEB) are synchronized
with respect to the LOW-to-HIGH transition of RCLKA (RCLKB).
The Write and Read Clock can be asynchronous or coincident.
0
1
No Operation
1
0
Write Into FIFO
1
1
No Operation
NOTE:
4093 tbl 08
1. For the purposes of this table, WENA2 and WENB2 = VIH.
2. The same selection sequence applies to reading from the registers. RENA1 and RENA2
(RENB1 and RENB2) are enabled and read is performed on the LOW-to-HIGH transition
of RCLKA (RCLKB).
Read Enables (RENA1, RENA2, RENB1, RENB2) — When both Read
Enables, RENA1, RENA2 (RENB1, RENB2) are LOW, data is read from Array
A (B) to the output register on the LOW-to-HIGH transition of the Read Clock,
RCLKA (RCLKB).
Figure 2. Writing to Offset Registers for FIFOs A and B
6
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
contains four 8-bit offset registers which can be loaded with data on the inputs,
or read on the outputs. See Figure 3 for details of the size of the registers and
the default values.
If FIFO A (B) is configured to have programmable flags, when the WENA1
(WENB1) and WENA2/LDA (WENB2/LDB) are set LOW, data on the DA (DB)
inputs are written into the Empty (Least Significant Bit) Offset register on the first
LOW-to-HIGH transition of the WCLKA (WCLKB). Data are written into the
Empty (Most Significant Bit) Offset register on the second LOW-to-HIGH
transition of WCLKA (WCLKB), into the Full (Least Significant Bit) Offset register
on the third transition, and into the Full (Most Significant Bit) Offset register on
the fourth transition. The fifth transition of WCLKA (WCLKB) again writes to the
Empty (Least Significant Bit) Offset register.
72V801 - 256 x 9 x 2
8
0
8
0
7
7
0
8
8
8
(MSB)
0
00
0
8
7
0
0
8
8
(MSB)
0
00
72V851 - 8,192 x 9 x 2
0
7
8
0
7
Empty Offset (LSB) Reg.
Empty Offset (LSB)
Empty Offset (LSB)
Default Value 007H
Default Value 007H
Default Value 007H
0
2
3
8
0
1
(MSB)
72V841 - 4,096 x 9 x 2
0
0
Full Offset (LSB) Reg.
Default Value 007H
1
8
0
1
Default Value 007H
0
4
8
0
(MSB)
(MSB)
(MSB)
000
0000
00000
7
0
8
Full Offset (LSB) Reg.
Default Value 007H
8
8
(MSB)
7
72V831 - 2,048 x 9 x 2
7
Default Value 007H
0
Full Offset (LSB)
0
0
Empty Offset (LSB) Reg.
1
Full Offset (LSB) Reg.
Default Value 007H
8
7
Default Value 007H
0
8
8
Empty Offset (LSB)
Default Value 007H
8
8
72V821 - 1,024 x 9 x 2
72V811 - 512 x 9 x 2
7
Empty Offset (LSB) Reg.
8
However, writing all offset registers does not have to occur at one time. One
or two offset registers can be written and then by bringing LDA (LDB) HIGH,
FIFO A (B) is returned to normal read/write operation. When LDA (LDB) is set
LOW, and WENA1 (WENB1) is LOW, the next offset register in sequence is
written.
The contents of the offset registers can be read on the QA (QB) outputs when
WENA2/LDA (WENB2/LDB) is set LOW and both Read Enables RENA1,
RENA2 (RENB1, RENB2) are set LOW. Data can be read on the LOW-to-HIGH
transition of the Read Clock RCLKA (RCLKB).
A read and write should not be performed simultaneously to the offset
registers.
0
2
0
7
8
0
7
Full Offset (LSB)
Full Offset (LSB)
Default Value 007H
Default Value 007H
3
8
0
8
4
0
(MSB)
(MSB)
(MSB)
000
0000
00000
4093 drw 05
Figure 3. Offset Register Formats and Default Values for the A and B FIFOs
7
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
OUTPUTS:
the IDT72V831's FIFO A (B), (4,096-m) writes to the IDT72V841's FIFO A
(B), or (8,1912-m) writes to the IDT72V851's FIFO A (B).
FFA (FFB) is synchronized with respect to the LOW-to-HIGH transition of
the Write Clock WCLKA (WCLKB). The offset “m” is defined in the Full Offset
Registers.
If there is no Full offset specified, PAFA (PAFB) will go LOW at Full-7 words.
PAFA (PAFB) is synchronized with respect to the LOW-to-HIGH transition
of the Write Clock WCLKA (WCLKB).
Full Flag (FFA, FFB) — FFA (FFB) will go LOW, inhibiting further write
operations, when Array A (B) is full. If no reads are performed after reset,
FFA (FFB) will go LOW after 256 writes to the IDT72V801's FIFO A (B), 512
writes to the IDT72V811's FIFO A (B), 1,024 writes to the IDT72V821's FIFO
A (B), 2,048 writes to the IDT72V831's FIFO A (B), 4,096 writes to the
IDT72V841's FIFO A (B), or 8,192 writes to the IDT72V851's FIFO A (B).
FFA (FFB) is synchronized with respect to the LOW-to-HIGH transition of
the Write Clock WCLKA (WCLKB).
Programmable Almost–Empty Flag (PAEA, PAEB) — PAEA (PAEB) will
go LOW when the read pointer is "n+1" locations less than the write pointer.
The offset "n" is defined in the Empty Offset Registers. If no reads are performed
after reset, PAEA (PAEB) will go HIGH after "n+1" writes to FIFO A (B).
If there is no Empty offset specified, PAEA (PAEB) will go LOW at Empty+7
words.
PAEA (PAEB) is synchronized with respect to the LOW-to-HIGH transition
of the Read Clock RCLKA (RCLKB).
Empty Flag (EFA, EFB) — EFA (EFB) will go LOW, inhibiting further read
operations, when the read pointer is equal to the write pointer, indicating that
Array A (B) is empty.
EFA (EFB) is synchronized with respect to the LOW-to-HIGH transition of
the Read Clock RCLKA (RCLKB).
Programmable Almost–Full Flag (PAFA, PAFB) — PAFA (PAFB) will go
LOW when the amount of data in Array A (B) reaches the Almost-Full condition.
If no reads are performed after reset, PAFA (PAFB) will go LOW after (256-m)
writes to the IDT72V801's FIFO A (B), (512-m) writes to the IDT72V811's FIFO
A (B), (1,024-m) writes to the IDT72V821's FIFO A (B), (2,048-m) writes to
Data Outputs (QA0 – QA8, QB0 – QB8 ) — QA0 - QA8 are the nine data
outputs for memory array A, QB0 - QB8 are the nine data outputs for memory
array B.
TABLE 1: STATUS FLAGS FOR A AND B FIFOS
NUMBER OF WORDS IN ARRAY A
FFA
PAFA
PAEA
EFA
NUMBER OF WORDS IN ARRAY B
FFB
PAFB
PAEB
EFB
L
IDT72V801
IDT72V811
IDT72V821
0
0
0
H
H
1 to n(1)
1 to n(1)
1 to n(1)
H
H
L
H
(n+1) to (256-(m+1))
(n+1) to (512-(m+1))
(n+1) to (1,024-(m+1))
H
H
H
H
(256-m)(2) to 255
(512-m)(2) to 511
(1,024-m)(2) to 1,023
H
L
H
H
256
512
1,024
L
L
H
H
FFA
PAFA
PAEA
EFA
FFB
PAFB
PAEB
EFB
NUMBER OF WORDS IN ARRAY A
NUMBER OF WORDS IN ARRAY B
IDT72V831
IDT72V841
L
IDT72V851
0
0
0
H
H
L
L
1 to n(1)
1 to n(1)
1 to n(1)
H
H
L
H
(n+1) to (2,048-(m+1))
(n+1) to (4,096-(m+1))
(n+1) to (8,192-(m+1))
H
H
H
H
(2,048-m)(2) to 2,047
(4,096-m)(2) to 4,095
(8,192-m)(2) to 8,191
H
L
H
H
2,048
4,096
8,192
L
L
H
H
NOTES:
1. n = Empty Offset (n = 7 default value)
2. m = Full Offset (m = 7 default value)
8
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
tRS
RSA (RSB)
tRSS
tRSR
tRSS
tRSR
tRSS
tRSR
RENA1, RENA2
(RENB1, RENB2)
WENA1
(WENB1)
WENA2/LDA (1)
(WENB2/LDB)
tRSF
EFA, PAEA
(EFB, PAEB)
tRSF
FFA, PAFA
(FFA, PAFA)
tRSF
(2)
OEA (OEB) = 1
QA0 - QA8
(QB0 - QB8)
OEA (OEB) = 0
4093 drw 06
NOTES:
1. Holding WENA2/LDA (WENB2/LDB) HIGH during reset will make the pin act as a second Write Enable pin. Holding WENA2/LDA (WENB2/LDB) LOW during reset will make
the pin act as a load enable for the programmable flag offset registers.
2. After reset, QA0 - QA8 (QB0 - QB8) will be LOW if OEA (OEB) = 0 and tri-state if OEA (OEB) = 1.
3. The clocks RCLKA, WCLKA (RCLKB, WCLKB) can be free-running during reset.
Figure 4. Reset Timing
tCLK
tCLKH
tCLKL
WCLKA (WCLKB)
tDH
tDS
(DA0 - DA8
DB0 - DB8)
DATA IN VALID
tENS
WENA1
(WENB1)
tENH
NO OPERATION
tENS
tENH
WENA2 (WENB2)
(If Applicable)
NO OPERATION
tWFF
tWFF
FFA
(FFB)
tSKEW1(1)
RCLKA (RCLKB)
RENA1, RENA2
(RENB1, RENB2)
4093 drw 07
NOTE:
1. tSKEW1 is the minimum time between a rising RCLKA (RCLKB) edge and a rising WCLKA (WCLKB) edge for FFA (FFB) to change during the current clock cycle. If the time
between the rising edge of RCLKA (RCLKB) and the rising edge of WCLKA (WCLKB) is less than tSKEW1, then FFA (FFB) may not change state until the next WCLKA (WCLKB)
edge.
Figure 5. Write Cycle Timing
9
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
RCLKA (RCLKB)
tENH
tENS
RENA1, RENA2
(RENB1, RENB2)
NO OPERATION
tREF
tREF
EFA (EFB)
tA
QA0 - QA8
(QB0 - QB8)
VALID DATA
tOLZ
tOHZ
tOE
OEA (OEB)
(1)
tSKEW1
WCLKA, WCLKB
WENA1 (WENB1)
WENA2 (WENB2)
4093 drw 08
NOTE:
1. tSKEW1 is the minimum time between a rising WCLKA (WCLKB) edge and a rising RCLKA (RCLKB) edge for EFA (EFB) to change during the current clock cycle. If the time
between the rising edge of RCLKA (RCLKB) and the rising edge of WCLKA (WCLKB) is less than tSKEW1, then EFA (EFB) may not change state until the next RCLKA (RCLKB)
edge.
Figure 6. Read Cycle Timing
WCLKA
(WCLKB)
tDS
DA0 - DA8
(DB0 - DB8)
D1
tENS
D2
D3
D0 (First Valid
WENA1
(WENB1)
tENS
WENA2 (WENB2)
(If Applicable)
tSKEW1
tFRL(1)
RCLKA
(RCLKB)
tREF
EFA (EFB)
tENS
RENA1, RENA2
(RENB1, RENB2)
tA
QA0 - QA8
(QB0 - QB8)
tA
D0
D1
tOLZ
tOE
OEA (OEB)
4093 drw 09
NOTE:
1. When tSKEW1 ≥ minimum specification, tFRL = tCLK + tSKEW1
When tSKEW1 < minimum specification, tFRL = 2tCLK + tSKEW1 or tCLK + tSKEW1
The Latency Timings apply only at the Empty Boundary (EFA, EFB = LOW).
Figure 7. First Data Word Latency Timing
10
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
NO WRITE
WCLKA
(WCLKB)
NO WRITE
tSKEW1
tDS
NO WRITE
tSKEW1
tDH
DA0 - DA8
(DB0 - DB8)
tWFF
tWFF
tWFF
FFA (FFB)
(1)
tENS
tENH
tENS
tENS
tENH
tENS
WENA1
(WENB1)
(1)
WENA2
(WENB2)
(If Applicable)
RCLKA
(RCLKB)
tENS
tENH
tENS
tENH
RENA1
(RENB2)
tA
OEA LOW
(OEB)
QA0 - QA8
(QB0 - QB8)
tA
DATA READ
DATA IN OUTPUT REGISTER
NEXT DATA READ
4093 drw 10
NOTE:
1. Only one of the two Write Enable inputs, WEN1 or WEN2, needs to go inactive to inhibit writes to the FIFO.
Figure 8. Full Flag Timing
WCLKA (WCLKB)
tDS
tDS
DA0 - DA8
(DB0 - DB8)
DATA WRITE 1
tENS
tENH
tENS
tENH
DATA WRITE 2
tENS
tENH
WENA1, (WENB1)
tENS
tENH
WENA2 (WENB2)
(If Applicable)
(1)
(1)
tSKEW1
tFRL
tSKEW1
tFRL
RCLKA (RLCKB)
tREF
tREF
tREF
EFA (EFB)
RENA1, RENA2
(RENB1, RENB2)
OEA (OEB)
LOW
tA
QA0 - QA8
(QB0 - QB8)
DATA READ
DATA IN OUTPUT REGISTER
4093 drw 11
NOTE:
1. When tSKEW1 ≥ minimum specification, tFRL maximum = tCLK + tSKEW1
When tSKEW1 < minimum specification, tFRL maximum = 2tCLK + tSKEW1 or tCLK + tSKEW1
The Latency Timings apply only at the Empty Boundary (EFA, EFB = LOW).
Figure 9. Empty Flag Timing
11
IDT72V801/72V811/72V821/72V831/72V841/72V851
tCLKH
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
tCLKL
WCLKA
(WCLKB)
(4)
tENS
tENH
tENS
tENH
WENA1
(WENB1
WENA2
(WENB2)
(If Applicable)
tPAF
PAFA
(PAFB)
Full - (m+1) words in FIFO
(1)
Full - m words in FIFO
(2)
(3)
tSKEW2
tPAF
RCLKA
(RCLKB)
tENS
tENH
RENA1, RENA2
(RENB1, RENB2)
4093 drw 12
NOTES:
1. m = PAF offset.
2. (256-m) words for the IDT72V801, (512-m) words the IDT72V811, (1,024-m) words for the IDT72V821, (2,048-m) words for the IDT72V831, (4,096-m) words for the IDT72V841,
or (8,192-m) words for the IDT72V851.
3. tSKEW2 is the minimum time between a rising RCLKA (RCLKB) edge and a rising WCLKA (WCLKB) edge for PAFA (PAFB) to change during that clock cycle. If the time between
the rising edge of RCLKA (RCLKB) and the rising edge of WCLKA (WCLKB) is less than tSKEW2, then PAFA (PAFB) may not change state until the next WCLKA (WCLKB)
rising edge.
4. If a write is performed on this rising edge of the Write Clock, there will be Full - (m-1) words in FIFO A (B) when PAFA (PAFB) goes LOW.
Figure 10. Programmable Full Flag Timing
tCLKH
tCLKL
WCLKA
(WCLKB)
tENS
tENH
tENS
tENH
WENA1
(WENB1)
WENA2
(WENB2)
(If Applicable)
PAEA,
PAEB
n words in FIFO
(1)
tSKEW2 (2)
n+1 words in FIFO
tPAE
tPAE
(3)
RCLKA
(RCLKB)
tENS
RENA1, RENA2
(RENB1, RENB2)
tENH
4093 drw 13
NOTES:
1. n = PAE offset.
2. tSKEW2 is the minimum time between a rising WCLKA (WCLKB) edge and a rising RCLKA (RCLKB) edge for PAEA (PAEB) to change during that clock cycle. If the time between
the rising edge of WCLKA (WCLKB) and the rising edge of RCLKA (RCLKB) is less than tSKEW2, then PAEA (PAEB) may not change state until the next RCLKA (RCLKB)
rising edge.
3. If a read is performed on this rising edge of the Read Clock, there will be Empty + (n-1) words in FIFO A (B) when PAEA (PAEB) goes LOW.
Figure 11. Programmable Empty Flag Timing
12
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
WCLKA (WCLKB)
tENH
tENS
LDA (LDB)
tENS
WENA1 (WENB1)
tDS
tDH
DA0 - DA7
(DB0 - DB7)
PAE OFFSET
(LSB)
PAE OFFSET
(MSB)
PAF OFFSET
(LSB)
PAF OFFSET
(MSB)
4093 drw 14
Figure 12. Write Offset Register Timing
tCLK
tCLKH
tCLKL
RCLKA (RCLKB)
tENS
tENH
LDA (LDB)
tENS
RENA1, RENA2
(RENB1, RENB2)
tA
QA0 - QA7
(QB0 - QB7)
DATA IN OUTPUT REGISTER
EMPTY OFFSET
(LSB)
EMPTY OFFSET
(MSB)
FULL OFFSET
(LSB)
FULL OFFSET
(MSB)
4093 drw 15
Figure 13. Read Offset Register Timing
13
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
OPERATING CONFIGURATIONS
be grounded (see Figure 14). In this configuration, the Write Enable 2/Load
WENA2/LDA (WENB2/LDB) pin is set LOW at Reset so that the pin operates
as a control to load and read the programmable flag offsets.
SINGLE DEVICE CONFIGURATION — When FIFO A (B) is in a Single
Device Configuration, the Read Enable 2 RENA2 (RENB2) control input can
RSA (RSB)
WCLKA (WCLKB)
RCLKA (RCLKB)
IDT
72V801
72V811
72V821
72V831
72V841
72V851
FIFO
A (B)
WENA1 (WENB1)
WENA2/LDA (WENB2/LDB)
DA0 - DA8 (DB0 - DB8)
FFA (FFB)
PAFA (PAFB)
RENA1 (RENB1)
OEA (OEB)
QA0 - QA8 (QB0 - QB8)
EFA (EFB)
PAEA (PAEB)
RENA2 (RENB2)
4093 drw 16
Figure 14. Block Diagram of One of the IDT72V801/72V811/72V821/72V831/72V841/72V851's
two FIFOs configured as a single device
WIDTH EXPANSION CONFIGURATION — Word width may be increased simply by connecting the corresponding input control signals of
FIFOs A and B. A composite flag should be created for each of the endpoint status flags EFA and EFB, also FFAand FFB). The partial status flags PAEA,
PAFB, PAEA and PAFB can be detected from any one device. Figure 15
demonstrates an 18-bit word width using the two FIFOs contained in one
IDT72V801/72V811/72V821/72V831/72V841/72V851. Any word width can
be attained by adding additional IDT72V801/72V811/72V821/72V831/
72V841/72V851s.
When these devices are in a Width Expansion Configuration, the Read
Enable 2 (RENA2 and RENB2) control inputs can be grounded (see Figure
15). In this configuration, the Write Enable 2/Load (WENA2/LDA, WENB2/LDB)
pins are set LOW at Reset so that the pin operates as a control to load and read
the programmable flag offsets.
9
RESET
RSA
DATA IN
18
9
DA0 - DA8
WRITE CLOCK
WCLKA
WRITE ENABLE
WENA1
WRITE ENABLE/LOAD
WENA2/LDA
FULL FLAG
FFA
FFB
DB0 - DB8
RAM
ARRAY RCLKA
WCLKB
A
256x9 RENA1
WENB1
512x9
1,024x9 OEA1
2,048x9 2WENB2/LDB
4,096x9
8,192x9
RENA2
RSB
RAM
ARRAY
B
256x9
512x9
1,024x9
2,048x9
4,096x9
8,192x9
EFA
EFB
EMPTY FLAG
RCLKB
READ CLOCK
RENB1
READ ENABLE
OEB
QB0 - QB8
OUTPUT ENABLE
9
18
DATA OUT
QA0 - QA8 RENB2
9
Figure 15. Block diagram of the two FIFOs contained in one IDT72V801/72V811/72V821/72V831/72V841/72V851
configured for an 18-bit width-expansion
14
4093 drw 17
IDT72V801/72V811/72V821/72V831/72V841/72V851
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE
TWO PRIORITY DATA BUFFER
CONFIGURATION
the intermixed data according to type, sending one kind to FIFO A and the other
kind to FIFO B. Then, at the outputs, each data type is transferred to its
appropriate destination. Additional IDT72V801/72V811/72V821/72V831/
72V841/72V851s permit more than two priority levels. Priority buffering is
particularly useful in network applications.
The two FIFOs contained in the IDT72V801/72V811/72V821/72V831/
72V841/72V851 can be used to prioritize two different types of data shared
on a system bus. When writing from the bus to the FIFO, control logic sorts
Image
Processing
Card
RAM ARRAY A
RCLKA
WCLKA
OEA
WENA1 RENA
Control
Logic
9
Clock
DA0-DA8
Data
9
Voice
Processing
Card
RAM ARRAY B
WCLKB RCLKB
WENB1
RAM
9
Clock
OEB2
RENB1
Control
Logic
Control
9-bit bus
Address
I/O Data
Data
IDT
72V801
72V811
72V821
72V831
72V841
72V851
Control
Logic
Processor
Clock
Control
9
QA0-QA8
WENA2 RENA2
VCC
Address
DB0-DB8
QB0-QB8
WENB2 RENB2
9
9
Address
Control
I/O Data
Data
4093 drw 18
VCC
Figure 16. Block Diagram of Two Priority Configuration
BIDIRECTIONAL CONFIGURATION
The two FIFOs of the IDT72V801/72V811/72V821/72V831/72V841/
72V851 can be used to buffer data flow in two directions. In the example that
RAM ARRAY A
WENA2 RENA2
VCC
WCLKA
WENA1
9
DMA Clock
Control
Logic
9-bit bus
Data
Peripheral
Controller
9
9-bit bus
Control
OEA
IDT
72V801
72V811
72V821
72V831
72V841
72V851
Control
Logic
Address
RCLKA
RENA1
DA0-DA8
QA0-QA8
9
Processor
Clock
follows, a processor can write data to a peripheral controller via FIFO A, and,
in turn, the peripheral controller can write the processor via FIFO B.
RAM ARRAY B
RCLKB
WENB1
RENB1
RAM
9
9
WCLKB
OEB
QB0-QB8
DB0-DB8
RENB2 WENB2
Address
Control
I/O Data
Data
9
9
4093 drw 19
VCC
Figure 17. Block Diagram of Bidirectional Configuration
15
DEPTH EXPANSION — These FIFOs can be adapted to applications that
require greater than 256/512/1,024/2,048/4,096/8,192 words. The existence of double enable pins on the read and write ports allow depth expansion.
The Write Enable 2/Load (WENA2, WENB2) pins are used as a second write
enables in a depth expansion configuration, thus the Programmable flags are
set to the default values. Depth expansion is possible by using one enable
input for system control while the other enable input is controlled by expansion
logic to direct the flow of data. A typical application would have the expansion
logic alternate data access from one device to the next in a sequential manner.
The IDT72V801/72V811/72V821/72V831/72V841/72V851 operates in the
Depth Expansion configuration when the following conditions are met:
1. WENA2/LDA and WENB2/LDB pins are held HIGH during Reset so that
these pins operate as second Write Enables.
2. External logic is used to control the flow of data.
Please see the Application Note "DEPTH EXPANSION OF IDT'S SYNCHRONOUS FIFOs USING THE RING COUNTER APPROACH" for
details of this configuration.
ORDERING INFORMATION
IDT
XXXXX
Device Type
L
Power
XX
Speed
PF
Package
Process/
Temperature
Range
BLANK
I(1)
PF
TF
Commercial (0°C to +70°C)
Industrial (-40°C to +85°C)
Thin Quad Flatpack (TQFP, PN64-1)
Slim Thin Plastic Quad Flatpack (STQFP, PP64-1)
10
15
20
Commercial Only
Commercial And Industrial
Commercial Only
L
Low Power
72V801
72V811
72V821
72V831
72V841
72V851
256 x 9  3.3 Volt DUAL SyncFIFO
512 x 9  3.3 Volt DUAL SyncFIFO
1,024 x 9  3.3 Volt DUAL SyncFIFO
2,048 x 9  3.3 Volt DUAL SyncFIFO
4,096 x 9  3.3 Volt DUAL SyncFIFO
8,192 x 9  3.3 Volt DUAL SyncFIFO
Clock Cycle Time
(tCLK), speed in
Nanoseconds
4093 drw 20
NOTE:
1. Industrial temperature range product for the 15ns speed grade is available as a standard device.
DATASHEET DOCUMENT HISTORY
04/24/2001
pgs. 4, 5 and 16
CORPORATE HEADQUARTERS
2975 Stender Way
Santa Clara, CA 95054
for SALES:
800-345-7015 or 408-727-6116
fax: 408-492-8674
www.idt.com
for TECH SUPPORT:
(408) 330-1753
[email protected]
PF Pkg: www.idt.com/docs/PSC4036.pdf
TF Pkg: www.idt.com/docs/PSC4046.pdf
The SyncFIFO is a trademark and the IDT logo is a registered trademark of Integrated Device Technology, Inc.
16
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