IDT IDT72V3612 3.3 volt cmos syncbififo-tm 64 x 36 x 2 Datasheet

3.3 VOLT CMOS SyncBiFIFOTM
64 x 36 x 2
•
FEATURES:
•
•
•
•
•
•
•
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Two independent clocked FIFOs (64 x 36 storage capacity each)
buffering data in opposite directions
Supports clock frequencies up to 83 MHz
Fast access times of 8ns
Free-running CLKA and CLKB can be asynchronous or
coincident (simultaneous reading and writing of data on a
single clock edge is permitted)
Mailbox bypass Register for each FIFO
Programmable Almost-Full and Almost-Empty Flags
Microprocessor interface control logic
EFA , FFA , AEA , and AFA flags synchronized by CLKA
EFB , FFB , AEB , and AFB flags synchronized by CLKB
•
•
IDT72V3612
Passive parity checking on each port
Parity generation can be selected for each port
Available in 132-pin plastic quad flat package (PQF), or space
saving 120-pin thin quad flat package (TQFP)
Pin and functionally compatible version of the 5V operating
IDT723612
Industrial temperature range (–40°°C +85°°C) is available
DESCRIPTION:
The IDT72V3612 is a pin and functionally compatible version of the
IDT723612, designed to run off a 3.3V supply for exceptionally low-power
consumption. This device is a monolithic high-speed, low-power CMOS bidirectional clocked FIFO memory. It supports clock frequencies up to 83 MHz
FUNCTIONAL BLOCK DIAGRAM
Port-A
Control
Logic
MBF1
RAM
ARRAY
64 x 36
Device
Control
Write
Pointer
FFA
AFA
EFA
AEA
Read
Pointer
EFB
AEB
Status Flag
Logic
36
FS0
FS1
A0 - A35
FIFO1
Programmable Flag
Offset Register
B0 - B36
FIFO2
FFB
AFB
Status Flag
Logic
Parity
Generation
Output
Register
Read
Pointer
PGA
PEFA
36
Write
Pointer
RAM
ARRAY
64 x 36
36
Input
Register
ODD/
EVEN
PGB
Parity
Generation
Input
Register
RST
PEFB
Parity
Gen/Check
Mail 1
Register
Output
Register
CLKA
CSA
W/RA
ENA
MBA
Mail 2
Register
Parity
Gen/Check
Port-B
Control
Logic
MBF2
CLKB
CSB
W/RB
ENB
MBB
4659 drw 01
IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc. SyncBiFIFO is a trademark of Integrated Device Technology, Inc.
COMMERCIAL TEMPERATURE RANGE
MAY 2003
1
2003 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.
DSC-4659/1
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
and has read access times as fast as 8ns. The FIFO operates in IDT Standard
mode. Two independent 64 x 36 dual-port SRAM FIFOs on board the chip
buffer data in opposite directions. Each FIFO has flags to indicate empty and
full conditions and two programmable flags (Almost-Full and Almost-Empty) to
indicate when a selected number of words is stored in memory. Communication
between each port can bypass the FIFOs via two 36-bit mailbox registers. Each
mailbox register has a flag to signal when new mail has been stored. Parity is
checked passively on each port and may be ignored if not desired. Parity
generation can be selected for data read from each port. Two or more devices
can be used in parallel to create wider data paths.
This device is a clocked FIFO, which means each port employs a
synchronous interface. All data transfers through a port are gated to the
LOW-to-HIGH transition of a port clock by enable signals. The clocks for
each port are independent of one another and can be asynchronous or
coincident. The enables for each port are arranged to provide a simple bidirectional interface between microprocessors and/or buses with synchronous control.
The Full Flag (FFA, FFB) and Almost-Full (AFA, AFB) flag of a FIFO
are two-stage synchronized to the port clock that writes data to its array.
The Empty Flag (EFA, EFB) and Almost-Empty (AEA, AEB) flag of a
FIFO are two stage synchronized to the port clock that reads data from
its array.
The IDT72V3612 is characterized for operation from 0°C to 70°C.
Industrial temperature range (–40°C to +85°C) is available by special order.
This device is fabricated using IDT's high speed, submicron CMOS
technology.
*
116
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35
36
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43
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45
46
47
48
49
50
GND
AEB
EFB
B0
B1
B2
GND
B3
B4
B5
B6
VCC
B7
B8
B9
GND
B10
B11
VCC
B12
B13
B14
GND
B15
B16
B17
B18
B19
B20
GND
B21
B22
B23
VCC
A24
A25
A26
GND
A27
A28
A29
VCC
A30
A31
A32
GND
A33
A34
A35
GND
B35
B34
B33
GND
B32
B31
B30
VCC
B29
B28
B27
GND
B26
B25
B24
VCC
GND
AEA
EFA
A0
A1
A2
GND
A3
A4
A5
A6
VCC
A7
A8
A9
GND
A10
A11
VCC
A12
A13
A14
GND
A15
A16
A17
A18
A19
A20
GND
A21
A22
A23
17
16
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9
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6
5
4
3
2
1
132
131
130
129
128
127
126
125
124
123
122
121
120
119
118
117
AFA
FFA
CSA
ENA
CLKA
W/RA
VCC
PGA
PEFA
GND
MBF2
MBA
FS1
FS0
ODD/EVEN
RST
GND
NC
NC
NC
NC
MBB
MBF1
GND
PEFB
PGB
VCC
W/RB
CLKB
ENB
CSB
FFB
AFB
PIN CONFIGURATIONS
*
4659 drw 02
Electrical pin 1 in center of beveled edge. Pin 1 identifier in corner.
NOTES:
1. NC - No internal connection
2. Uses Yamaichi socket IC51-1324-828
PQFP(2) (PQ132-1, order code: PQF)
TOP VIEW
2
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
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A24
A25
A26
VCC
A27
A28
A29
GND
A30
A31
A32
A33
A34
A35
GND
B35
B34
B33
B32
B31
B30
GND
B29
B28
B27
VCC
B26
B25
B24
B23
PIN CONFIGURATIONS (CONTINUED)
1
2
3
4
5
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63
62
61
B22
B21
GND
B20
B19
B18
B17
B16
B15
B14
B13
B12
B11
B10
GND
B9
B8
B7
VCC
B6
B5
B4
B3
GND
B2
B1
B0
EFB
AEB
AFB
NOTE:
1. NC - No internal connection
AFA
FFA
CSA
ENA
CLKA
W/RA
VCC
PGA
PEFA
MBF2
MBA
FS1
FS0
ODD/EVEN
RST
GND
NC
NC
NC
NC
MBB
MBF1
PEFB
PGB
VCC
W/RB
CLKB
ENB
CSB
FFB
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
A23
A22
A21
GND
A20
A19
A18
A17
A16
A15
A14
A13
A12
A11
A10
GND
A9
A8
A7
VCC
A6
A5
A4
A3
GND
A2
A1
A0
EFA
AEA
TQFP (PN120-1, order code: PF)
TOP VIEW
3
4659 drw 03
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTION
Symbol
Name
I/O
I/O
Description
A0-A35
Port A Data
36-bit bidirectional data port for side A.
AEA
Port A Almost-Empty
Flag
O
(Port A)
Programmable Almost-Empty flag synchronized to CLKA. It is LOW when the number of words in
the FIFO2 is less than or equal to the value in the offset register, X.
AEB
Port B Almost-Empty
Flag
O
(PortB)
Programmable Almost-Empty flag synchronized to CLKB. It is LOW when the number of words in
FIFO1 is less than or equal to the value in the offset register, X.
AFA
Port A Almost-Full
Flag
O
Programmable Almost-Full flag synchronized to CLKA. It is LOW when the number of empty
(Port A) locations in FIFO1 is less than or equal to the value in the offset register, X.
AFB
Port B Almost-Full
Flag
O
Programmable Almost-Full flag synchronized to CLKB. It is LOW when the number of empty
(Port B) locations in FIFO2 is less than or equal to the value in the offset register, X.
B0-B35
Port B Data.
I/O
CLKA
Port A Clock
I
CLKA is a continuous clock that synchronizes all data transfers through port A and can be
asynchronous or coincident to CLKB. EFA, FFA, AFA, and AEA are synchronized to the LOW-toHIGH transition of CLKA.
36-bit bidirectional data port for side B.
CLKB
Port B Clock
I
CLKB is a continuous clock that synchronizes all data transfers through port B and can be
asynchronous or coincident to CLKA. EFB, FFB, AFB, and AEB are synchronized to the LOW-toHIGH transition of CLKB.
CSA
Port A Chip Select
I
CSA must be LOW to enable a LOW-to-HIGH transition of CLKA to read or write data on port A.
The A0-A35 outputs are in the high-impedance state when CSA is HIGH.
CSB
Port B Chip Select
I
CSB must be LOW to enable a LOW-to-HIGH transition of CLKB to read or write data on port B.
The B0-B35 outputs are in the high-impedance state when CSB is HIGH.
EFA
Port A Empty Flag
O
EFA is synchronized to the LOW-to-HIGH transition of CLKA. When EFA is LOW, FIFO2 is empty,
(Port A) and reads from its memory are disabled. Data can be read from FIFO2 to the output register
when EFA is HIGH. EFA is forced LOW when the device is reset and is set HIGH by the second
LOW-to-HIGH transition of CLKA after data is loaded into empty FIFO2 memory.
EFB
Port B Empty Flag
O
EFB is synchronized to the LOW-to-HIGH transition of CLKB. When EFB is LOW, the FIFO1 is
(Port B) empty, and reads from its memory are disabled. Data can be read from FIFO1 to the output
register when EFB is HIGH. EFB is forced LOW when the device is reset and is set HIGH by the
second LOW-to-HIGH transition of CLKB after data is loaded into empty FIFO1 memory.
ENA
Port A Enable
I
ENA must be HIGH to enable a LOW-to-HIGH transition of CLKA to read or write data on port A.
ENB
Port B Enable
I
ENB must be HIGH to enable a LOW-to-HIGH transition of CLKB to read or write data on port B.
FFA
Port A Full Flag
O
FFA is synchronized to the LOW-to-HIGH transition of CLKA. When FFA is LOW, FIFO1 is full,
(Port A) and writes to its memory are disabled. FFA is forced LOW when the device is reset and is set
HIGH by the second LOW-to-HIGH transition of CLKA after reset.
FFB
Port B Full Flag
O
FFB is synchronized to the LOW-to-HIGH transition of CLKB. When FFB is LOW, FIFO2 is full,
(Port B) and writes to its memory are disabled. FFB is forced LOW when the device is reset and is set
HIGH by the second LOW-to-HIGH transition of CLKB after reset.
FS1, FS0
Flag Offset Selects
I
The LOW-to-HIGH transition of RST latches the values of FS0 and FS1, which selects one of four
preset values for the Almost-Full flag and Almost-Empty flag.
MBA
Port A Mailbox
Select
I
A HIGH level on MBA chooses a mailbox register for a port A read or write operation. When the
A0-A35 outputs are active, a HIGH level on MBA selects data from the mail2 register for output,
and a LOW level selects FIFO2 output register data for output.
MBB
Port B Mailbox
Select
I
A HIGH level on MBB chooses a mailbox register for a port B read or write operation. When the
B0-B35 outputs are active, a HIGH level on MBB selects data from the mail1 register for output,
and a LOW level selects FIFO1 output register data for output.
MBF1
Mail1 Register Flag
O
MBF1 is set LOW by a LOW-to-HIGH transition of CLKA that writes data to the mail1 register.
Writes to the mail1 register are inhibited while MBF1 is set LOW. MBF1 is set HIGH by a LOW-toHIGH transition of CLKB when a port B read is selected and MBB is HIGH. MBF1 is set HIGH
when the device is reset.
4
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTION (CONTINUED)
Symbol
Name
I/O
Description
MBF2
Mail2 Register Flag
O
MBF2 is set LOW by a LOW-to-HIGH transition of CLKB that writes data to the mail2 register.
Writes to the mail2 register are inhibited while MBF2 is set LOW. MBF2 is set HIGH by a LOW-toHIGH transition of CLKA when a port A read is selected and MBA is HIGH. MBF2 is set HIGH
when the device is reset.
ODD/
EVEN
Odd/Even Parity
Select
I
Odd parity is checked on each port when ODD/EVEN is HIGH, and even parity is checked when
ODD/EVEN is LOW. ODD/EVEN also selects the type of parity generated for each port if parity
generation is enabled for a read operation.
PEFA
Port A Parity Error
Flag
O
(Port A)
When any byte applied to terminals A0-A35 fails parity, PEFA is LOW. Bytes are organized as
A0-A8, A9-A17, A18-A26, and A27-A35, with the most significant bit of each byte serving as the
parity bit. The type of parity checked is determined by the state of the ODD/EVEN input. The
parity trees used to check the A0-A35 inputs are shared by the mail2 register to generate parity if
parity generation is selected by PGA. Therefore, if a mail2 read with parity generation is setup by
having W/RA LOW, MBA HIGH, and PGA HIGH, the PEFA flag is forced HIGH regardless of the
A0-A35 inputs.
PEFB
Port B Parity Error
Flag
O
(Port B)
When any byte applied to terminals B0-B35 fails parity, PEFB is LOW. Bytes are organized as
B0-B8, B9-B17, B18-B26, B27-B35 with the most significant bit of each byte serving as the parity
bit. The type of parity checked is determined by the state of the ODD/EVEN input. The parity trees
used to check the B0-B35 inputs are shared by the mail1 register to generate parity if parity
generation is selected by PGB. Therefore, if a mail1 read with parity generation is setup by having
W/RB LOW, MBB HIGH, and PGB HIGH, the PEFB flag is forced HIGH regardless of the state of
the B0-B35 inputs.
PGA
Port A Parity
Generation
I
Parity is generated for data reads from port A when PGA is HIGH. The type of parity generated is
selected by the state of the ODD/EVEN input. Bytes are organized as A0-A8, A9-A17, A18-A26,
and A27-A35. The generated parity bits are output in the most significant bit of each byte.
PGB
Port B Parity
Generation
I
Parity is generated for data reads from port B when PGB is HIGH. The type of parity generated is
selected by the state of the ODD/EVEN input. Bytes are organized as B0-B8, B9-B17, B18-B26,
and B27-B35. The generated parity bits are output in the most significant bit of each byte.
RST
Reset
I
To reset the device, four LOW-to-HIGH transitions of CLKA and four LOW-to-HIGH transitions of
CLKB must occur while RST is LOW. This sets the AFA, AFB, MBF1, and MBF2 flags HIGH and
the EFA, EFB, AEA, AEB, FFA, and FFB flags LOW. The LOW-to-HIGH transition of RST latches
the status of the FS1 and FS0 inputs to select Almost-Full and Almost-Empty flag offset.
W/RA
Port A Write/Read
Select
I
A HIGH selects a write operation and a LOW selects a read operation on port A for a LOW-toHIGH transition of CLKA. The A0-A35 outputs are in the high-impedance state when W/RA is
HIGH.
W/RB
Port B Write/Read
Select
I
A HIGH selects a write operation and a LOW selects a read operation on port B for a LOW-toHIGH transition of CLKB. The B0-B35 outputs are in the high-impedance state when W/RB is
HIGH.
5
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR
TEMPERATURE RANGE (Unless otherwise noted)(2)
Symbol
Rating
Commercial
Unit
VCC
Supply Voltage Range
–0.5 to +4.6
V
VI(2)
Input Voltage Range
–0.5 to VCC+0.5
V
VO(2)
Output Voltage Range
–0.5 to VCC+0.5
V
IIK
Input Clamp Current, (VI < 0 or VI > VCC)
±20
mA
IOK
Output Clamp Current, (VO < 0 or VO > VCC)
±50
mA
IOUT
Continuous Output Current, (VO = 0 to VCC)
±50
mA
ICC
Continuous Current Through VCC or GND
±500
mA
TSTG
Storage Temperature Range
–65 to 150
°C
NOTES:
1. Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at
these or any other conditions beyond those indicated under "Recommended Operating Conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended
periods may affect device reliability.
2. The input and output voltage ratings may be exceeded provided the input and output current ratings are observed.
RECOMMENDED OPERATING
CONDITIONS
Symbol
Parameter
Min. Typ.
Supply Voltage
VCC(1)
3.0
Max.
Unit
3.3
3.6
V
VIH
HIGH Level Input Voltage
2
—
VCC+0.5
V
VIL
LOW-Level Input Voltage
—
—
0.8
V
IOH
HIGH-Level Output Current
—
—
–4
mA
IOL
LOW-Level Output Current
—
—
8
mA
TA
Operating Free-air
Temperature
0
—
70
°C
NOTE:
1. For 12ns (83MHz operation), Vcc=3.3V +/-0.15V, JEDEC JESD8-A compliant
ELECTRICAL CHARACTERISTICS OVER RECOMMENDED OPERATING FREEAIR TEMPERATURE RANGE (Unless otherwise noted)
IDT72V3612
Commercial
tCLK = 12, 15, 20 ns
Symbol
Parameter
Test Conditions
Min.
Typ.(1)
Max.
Unit
VOH
Output Logic "1" Voltage
VCC = 3.0V,
IOH = –4 mA
2.4
—
—
V
VOL
Output Logic "0" Voltage
VCC = 3.0V,
IOL = 8 mA
—
—
0.5
V
ILI
Input Leakage Current (Any Input)
VCC = 3.6V,
VI = VCC or 0
—
—
±5
µA
Output Leakage Current
VCC = 3.6V,
VO = VCC or 0
—
—
±5
µA
Standby Current
VCC = 3.6V,
VI = VCC - 0.2V or 0
—
—
500
µA
CIN
Input Capacitance
VI = 0,
f = 1 MHz
—
4
—
pF
C OUT
Output Capacitance
VO = 0,
f = 1 MHZ
—
8
—
pF
ILO
ICC
(2)
NOTES:
1. All typical values are at VCC = 3.3V, TA = 25°C.
2. For additional ICC information, see Figure 1, Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS).
6
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
DETERMINING ACTIVE CURRENT CONSUMPTION AND POWER DISSIPATION
The ICC(f) current for the graph in Figure 1 was taken while simultaneously reading and writing the FIFO on the IDT72V3612 with CLKA and CLKB set to
fS. All data inputs and data outputs change state during each clock cycle to consume the highest supply current. Data outputs were disconnected to normalize
the graph to a zero-capacitance load. Once the capacitance load per data-output channel is known, the power dissipation can be calculated with the equation
below.
CALCULATING POWER DISSIPATION
With ICC(f) taken from Figure 1, the maximum power dissipation (PT) of the IDT72V3612 may be calculated by:
PT = VCC x ICC(f) + Σ(CL x (VOH - VOL)2 x fO)
N
where:
N
CL
fo
VOH
VOL
=
=
=
=
=
number of outputs = 36
output capacitance load
switching frequency of an output
output HIGH level voltage
output LOW level voltage
When no reads or writes are occurring on this device, the power dissipated by a single clock (CLKA or CLKB) input running at frequency fS is calculated
by:
PT = VCC x fS x 0.025 mA/MHz
175
150
ICC(f)
Supply Current
mA
fdata = 1/2 fS
TA = 25°C
125
CL = 0 pF
VCC = 3.6V
VCC = 3.3V
100
VCC = 3.0V
75
50
25
0
0
10
20
30
40
50
60
70
fS  Clock Frequency  MHz
Figure 1. Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS)
7
80
90
4663 drw 04
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
DC ELECTRICAL CHARACTERISTICS OVER RECOMMENDED RANGES OF
SUPPLY VOLTAGE AND OPERATING FREE-AIR TEMPERATURE
Commercial: Vcc=3.3V± 0.30V; for 12ns (83MHz) operation, Vcc=3.3V ±0.15V; TA = 0° C to +70°C; JEDEC JESD8-A compliant
Symbol
IDT72V3612L12
Min.
Max.
Parameter
IDT72V3612L15
Min.
Max.
IDT72V3612L20
Min.
Max.
Unit
fS
Clock Frequency, CLKA or CLKB
–
83
–
66.7
–
50
MHz
tCLK
Clock Cycle Time, CLKA or CLKB
12
–
15
–
20
–
ns
tCLKH
Pulse Duration, CLKA and CLKB HIGH
5
–
6
–
8
–
ns
tCLKL
Pulse Duration, CLKA and CLKB LOW
5
–
6
–
8
–
ns
tDS
Setup Time, A0-A35 before CLKA↑ and B0-B35 before
CLKB↑
4
–
4
–
5
–
ns
tENS1
Setup Time, CSA, W/RA before CLKA↑; CSB, W/RB
before CLKB↑
3.5
–
6
–
6
–
ns
tENS2
Setup Time, ENA, before CLKA↑; ENB before CLKB↑
3.5
–
4
–
5
–
ns
tENS3
Setup Time, MBA before CLKA↑: MBB before CLKB↑
3.5
–
4
–
5
–
ns
tPGS
Setup Time, ODD/EVEN and PGA before CLKA↑;
ODD/EVEN and PGB before CLKB↑(1)
3
–
4
–
5
–
ns
tRSTS
Setup Time, RST LOW before CLKA↑ or CLKB↑(2)
4
–
5
–
6
–
ns
tFSS
Setup Time, FS0/FS1 before RST HIGH
4
–
5
–
6
–
ns
tDH
Hold Time, A0-A35 after CLKA↑ and B0-B35 after CLKB↑
0.5
–
1
–
1
–
ns
tENH1
Hold Time, CSA W/RA after CLKA↑; CSB, W/RB after
CLKB↑
0.5
–
1
–
1
–
ns
tENH2
Hold Time, ENA, after CLKA↑; ENB after CLKB↑
1
–
1
–
1
–
ns
tENH3
Hold Time, MBA after CLKA↑; MBB after CLKB↑
1
–
1
–
1
–
ns
tPGH
Hold Time, ODD/EVEN and PGA after CLKA↑;
ODD/EVEN and PGB after CLKB↑(1)
0
–
1
–
1
–
ns
tRSTH
Hold Time, RST LOW after CLKA↑ or CLKB↑(2)
4
–
5
–
6
–
ns
Hold Time, FS0 and FS1 after RST HIGH
4
–
4
–
4
–
ns
tFSH
tSKEW1
Skew Time, between CLKA↑ and CLKB↑ for EFA, EFB,
FFA, and FFB
5.5
–
8
–
8
–
ns
tSKEW2(3,4)
Skew Time, between CLKA↑ and CLKB↑ for AEA, AEB,
AFA, and AFB
14
–
14
–
16
–
ns
(3)
NOTES:
1. Only applies for a clock edge that does a FIFO read.
2. Requirement to count the clock edge as one of at least four needed to reset a FIFO.
3. Skew time is not a timing constraint for proper device operation and is only included to illustrate the timing relationship between CLKA cycle and CLKB cycle.
4. Design simulated, not tested.
8
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
SWITCHING CHARACTERISTICS OVER RECOMMENDED RANGES OF
SUPPLY VOLTAGE AND OPERATING FREE-AIR TEMPERATURE, CL = 30pF
Commercial: Vcc=3.3V± 0.30V; for 12ns (83MHz) operation, Vcc=3.3V ±0.15V; TA = 0°C to +70°C; JEDEC JESD8-A compliant
Symbol
IDT72V3612L12
Min.
Max.
Parameter
IDT72V3612L15
Min.
Max.
IDT72V3612L20
Min.
Max.
Unit
tA
Access Time, CLKA↑ to A0-A35 and CLKB↑ to B0-B35
1
8
2
10
2
12
ns
tWFF
Propagation Delay Time, CLKA↑ to FFA and CLKB↑ to FFB
1
8
2
10
2
12
ns
tREF
Propagation Delay Time, CLKA↑ to EFA and CLKB↑ to EFB
1
8
2
10
2
12
ns
tPAE
Propagation Delay Time, CLKA↑ to AEA and CLKB↑ to AEB
1
8
2
10
2
12
ns
tPAF
Propagation Delay Time, CLKA↑ to AFA and CLKB↑ to AFB
1
8
2
10
2
12
ns
tPMF
Propagation Delay Time, CLKA↑ to MBF1 LOW or MBF2
HIGH and CLKB↑ to MBF2 LOW or MBF1 HIGH
1
8
1
9
1
12
ns
tPMR
Propagation Delay Time, CLKA↑ to B0-B35(1) and CLKB↑
to A0-A35(2)
2
8
2
10
2
12
ns
tMDV
Propagation Delay Time, MBA to A0-A35 valid and MBB to
B0-B35 valid
1
8
1
10
1
11.5
ns
tPDPE
Propagation Delay Time, A0-A35 valid to PEFA valid; B0-B35
valid to PEFB valid
2
8
2
10
2
11
ns
Propagation Delay Time, ODD/EVEN to PEFA and PEFB
2
8
2
10
2
12
ns
tPOPB
Propagation Delay Time, ODD/EVEN to parity bits (A8, A17,
A26, A35) and (B8, B17, B26, B35)
2
8
2
10
2
12
ns
tPEPE
Propagation Delay Time, W/RA, CSA, ENA, MBA or PGA to
PEFA; W/RB, CSB, ENB. MBB, PGB to PEFB
1
8
1
10
1
12
ns
tPEPB(3)
Propagation Delay Time, W/RA, CSA, ENA, MBA or PGA to
parity bits (A8, A17, A26, A35); W/RB, CSB, ENB. MBB or PGB
to parity bits (B8, B17, B26, B35)
2
8
2
10
2
12
ns
tRSF
Propagation Delay Time, RST to (AEA, AEB) LOW and
(AFA, AFB, MBF1, MBF2) HIGH
1
10
1
15
1
20
ns
tEN
Enable Time, CSA and W/RA LOW to A0-A35 active and
CSB LOW and W/RB HIGH to B0-B35 active
2
6
2
10
2
12
ns
tDIS
Disable Time, CSA or W/RA HIGH to A0-A35 at highimpedance and CSB HIGH or W/RB LOW to B0-B35 at
high impedance
1
6
1
8
1
9
ns
tPOPE
(3)
NOTES:
1. Writing data to the mail1 register when the B0-B35 outputs are active and MBB is HIGH.
2. Writing data to the mail2 register when the A0-A35 outputs are active and MBA is HIGH.
3. Only applies when reading data from a mail register.
9
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
Table 1. For the relevant Reset and preset value loading timing diagram, see
Figure 2.
SIGNAL DESCRIPTIONS
RESET
The IDT72V3612 is reset by taking the Reset (RST) input LOW for at
least four port A Clock (CLKA) and four port B Clock (CLKB) LOW-to-HIGH
transitions. The Reset input can switch asynchronously to the clocks. A
device reset initializes the internal read and write pointers of each FIFO and
forces the Full Flags (FFA, FFB) LOW, the Empty Flags (EFA, EFB) LOW,
the Almost-Empty flags (AEA, AEB) LOW and the Almost-Full flags (AFA,
AFB) HIGH. A reset also forces the Mailbox Flags (MBF1, MBF2) HIGH.
After a reset, FFA is set HIGH after two LOW-to-HIGH transitions of CLKA
and FFB is set HIGH after two LOW-to-HIGH transitions of CLKB. The
device must be reset after power up before data is written to its memory.
A LOW-to-HIGH transition on the RST input loads the Almost-Full and
Almost-Empty registers (X) with the values selected by the Flag Select (FS0,
FS1) inputs. The values that can be loaded into the registers are shown in
TABLE 1 – FLAG PROGRAMMING
FS1
FS0
RST
ALMOST-FULL AND
ALMOST-EMPTY FLAG
OFFSET REGISTER (X)
H
H
↑
16
H
L
↑
12
L
H
↑
8
L
L
↑
4
FIFO WRITE/READ OPERATION
The state of port A data A0-A35 outputs is controlled by the port A Chip
Select (CSA) and the port A Write/Read select (W/RA). The A0-A35 outputs
are in the high-impedance state when either CSA or W/RA is HIGH. The A0A35 outputs are active when both CSA and W/RA are LOW.
Data is loaded into FIFO1 from the A0-A35 inputs on a LOW-to-HIGH
transition of CLKA when CSA is LOW, W/RA is HIGH, ENA is HIGH, MBA
is LOW, and FFA is HIGH. Data is read from FIFO2 to the A0-A35 outputs
by a LOW-to-HIGH transition of CLKA when CSA is LOW, W/RA is LOW,
ENA is HIGH, MBA is LOW, and EFA is HIGH (see Table 2). Relevant Write
and Read timing diagrams for Port A can be found in Figure 3 and Figure
6.
The port B control signals are identical to those of port A. The state of
the port B data (B0-B35) outputs is controlled by the port B Chip Select
(CSB) and the port B Write/Read select (W/RB). The B0-B35 outputs are
in the high-impedance state when either CSB or W/RB is HIGH. The B0B35 outputs are active when both CSB and W/RB are LOW.
Data is loaded into FIFO2 from the B0-B35 inputs on a LOW-to-HIGH
transition of CLKB when CSB is LOW, W/RB is HIGH, ENB is HIGH, MBB
is LOW, and FFB is HIGH. Data is read from FIFO1 to the B0-B35 outputs
by a LOW-to-HIGH transition of CLKB when CSB is LOW, W/RB is LOW, ENB
is HIGH, MBB is LOW, and EFB is HIGH (see Table 3). Relevant Write and
Read timing diagrams for Port B can be found in Figure 4 and Figure 5.
The setup and hold time constraints to the port clocks for the port Chip Selects
(CSA, CSB) and Write/Read selects (W/RA, W/RB) are only for enabling write
TABLE 2 – PORT-A ENABLE FUNCTION TABLE
CSA
W/RA
ENA
MBA
CLKA
Data A (A0-A35) I/O
Port Functions
H
X
X
X
X
Input
None
L
H
L
X
X
Input
None
L
H
H
L
↑
Input
FIFO1 Write
L
H
H
H
↑
Input
Mail1 Write
L
L
L
L
X
Output
None
L
L
H
L
↑
Output
FIFO2 Read
L
L
L
H
X
Output
None
L
L
H
H
↑
Output
Mail2 Read (Set MBF2 HIGH)
TABLE 3 – PORT-B ENABLE FUNCTION TABLE
CSB
W/RB
ENB
MBB
CLKB
Data B (B0-B35) I/O
Port Functions
H
X
X
X
X
Input
None
L
H
L
X
X
Input
None
L
H
H
L
↑
Input
FIFO2 Write
L
H
H
H
↑
Input
Mail2 Write
L
L
L
L
X
Output
None
L
L
H
L
↑
Output
FIFO1 read
L
L
L
H
X
Output
None
L
L
H
H
↑
Output
Mail1 Read (Set MBF1 HIGH)
10
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
From the time a word is read from a FIFO, the previous memory location is ready
to be written in a minimum of three cycles of the Full Flag synchronizing clock.
Therefore, a Full Flag is LOW if less than two cycles of the Full Flag synchronizing
clock have elapsed since the next memory write location has been read. The
second LOW-to-HIGH transition on the Full Flag synchronization clock after the
read sets the Full Flag HIGH and the data can be written in the following clock
cycle.
A LOW-to-HIGH transition on a Full Flag synchronizing clock begins the
first synchronization cycle of a read if the clock transition occurs at time
tSKEW1 or greater after the read. Otherwise, the subsequent clock cycle can
be the first synchronization cycle (see Figure 9 and Figure 10).
and read operations and are not related to high-impedance control of the data
outputs. If a port enable is LOW during a clock cycle, the port chip select and
write/read select may change states during the setup and hold time window of
the cycle.
SYNCHRONIZED FIFO FLAGS
Each FIFO is synchronized to its port clock through two flip-flop stages.
This is done to improve flag reliability by reducing the probability of
metastable events on the output when CLKA and CLKB operate asynchronously to one another. EFA, AEA, FFA, and AFA are synchronized by
CLKA. EFB, AEB, FFB, and AFB are synchronized to CLKB. Tables 4 and
5 show the relationship of each port flag to FIFO1 and FIFO2.
EMPTY FLAGS (EFA, EFB)
The Empty Flag of a FIFO is synchronized to the port clock that reads
data from its array. When the Empty Flag is HIGH, new data can be read
to the FIFO output register. When the Empty Flag is LOW, the FIFO is empty
and attempted FIFO reads are ignored.
The read pointer of a FIFO is incremented each time a new word is
clocked to the output register. The state machine that controls an Empty
Flag monitors a write-pointer and read-pointer comparator that indicates
when the FIFO memory status is empty, empty+1, or empty+2. A word
written to a FIFO can be read to the FIFO output register in a minimum of
three cycles of the Empty Flag synchronizing clock. Therefore, an Empty
Flag is LOW if a word in memory is the next data to be sent to the FIFO output
register and two cycles of the port clock that reads data from the FIFO have
not elapsed since the time the word was written. The Empty Flag of the FIFO
is set HIGH by the second LOW-to-HIGH transition of the synchronizing
clock, and the new data word can be read to the FIFO output register in the
following cycle.
A LOW-to-HIGH transition on an Empty Flag synchronizing clock begins
the first synchronization cycle of a write if the clock transition occurs at time
tSKEW1 or greater after the write. Otherwise, the subsequent clock cycle can
be the first synchronization cycle (see Figure 7 and Figure 8).
ALMOST EMPTY FLAGS (AEA, AEB)
The Almost-Empty flag of a FIFO is synchronized to the port clock that
reads data from its array. The state machine that controls an Almost-Empty
flag monitors a write-pointer comparator that indicates when the FIFO
memory status is almost-empty, almost-empty+1, or almost-empty+2. The
almost-empty state is defined by the value of the Almost-Full and AlmostEmpty Offset register (X). This register is loaded with one of four preset
values during a device reset (see Reset section). An Almost-Empty flag is
LOW when the FIFO contains X or less words in memory and is HIGH when
the FIFO contains (X+1) or more words.
Two LOW-to-HIGH transitions of the Almost-Empty flag synchronizing clocks are required after a FIFO write for the Almost-Empty flag to reflect
the new level of fill. Therefore, the Almost-Empty flag of a FIFO containing
(X+1) or more words remains LOW if two cycles of the synchronizing clock
have not elapsed since the write that filled the memory to the (X+1) level.
An Almost-Empty flag is set HIGH by the second LOW-to-HIGH transition
of the synchronizing clock after the FIFO write that fills memory to the (X+1)
level. A LOW-to-HIGH transition of an Almost-Empty flag synchronizing
clock begins the first synchronization cycle if it occurs at time tSKEW2 or
greater after the write that fills the FIFO to (X+1) words. Otherwise, the
subsequent synchronizing clock cycle can be the first synchronization cycle
(see Figure 11 and 12).
FULL FLAG (FFA, FFB)
The Full Flag of a FIFO is synchronized to the port clock that writes data
to its array. When the Full Flag is HIGH, a memory location is free in the
FIFO to receive new data. No memory locations are free when the Full Flag
is LOW and attempted writes to the FIFO are ignored.
Each time a word is written to a FIFO, the write pointer is incremented. The
state machine that controls a Full Flag monitors a write-pointer and read pointer
comparator that indicates when the FIFO memory status is full, full-1, or full-2.
ALMOST FULL FLAGS (AFA, AFB)
The Almost-Full flag of a FIFO is synchronized to the port clock that
writes data to its array. The state machine that controls an Almost-Full flag
monitors a write-pointer and read-pointer comparator that indicates when the
FIFO memory status is almost-full, almost-full-1, or almost-full-2. The almost-full
state is defined by the value of the Almost-Full and Almost-Empty Offset register
(X). This register is loaded with one of four preset values during a device reset
(see Reset section). An Almost-Full flag is LOW when the FIFO contains (64-
TABLE 4 – FIFO1 FLAG OPERATION
TABLE 5 – FIFO2 FLAG OPERATION
Synchronized
Synchronized
to CLKB
to CLKA
Number of Words
Synchronized
to CLKB
to CLKA
Number of Words
in the FIFO1
EFB
AEB
AFA
FFA
in the FIFO2
0
L
L
H
H
1 to X
H
L
H
(X+1) to [64-(X+1)]
H
H
(64-X) to 63
H
64
H
(1)
Synchronized
EFA
AEA
AFB
FFB
0
L
L
H
H
H
1 to X
H
L
H
H
H
H
(X+1) to [64-(X+1)]
H
H
H
H
H
L
H
(64-X) to 63
H
H
L
H
H
L
L
64
H
H
L
L
NOTE:
1. X is the value in the Almost-Empty flag and Almost-Full flag offset register.
11
(1)
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
X) or more words in memory and is HIGH when the FIFO contains [64-(X+1)]
or less words.
Two LOW-to-HIGH transitions of the Almost-Full flag synchronizing
clock are required after a FIFO read for the Almost-Full flag to reflect the new
level of fill. Therefore, the Almost-Full flag of a FIFO containing [64-(X+1)]
or less words remains LOW if two cycles of the synchronizing clock have not
elapsed since the read that reduced the number of words in memory to
[64-(X+1)]. An Almost-Full flag is set HIGH by the second LOW-to-HIGH
transition of the synchronizing clock after the FIFO read that reduces the
number of words in memory to [64-(X+1)]. A second LOW-to-HIGH
transition of an Almost-Full flag synchronizing clock begins the first synchronization cycle if it occurs at time tSKEW2 or greater after the read that reduces
the number of words in memory to [64-(X+1)]. Otherwise, the subsequent
synchronizing clock cycle can be the first synchronization cycle (see Figure
13 and 14).
MAILBOX REGISTERS
Each FIFO has a 36-bit bypass register to pass command and control
information between port A and port B without putting it in queue. The
Mailbox select (MBA, MBB) inputs choose between a mail register and a
FIFO for a port data transfer operation. A LOW-to-HIGH transition on CLKA
writes A0-A35 data to the mail1 register when a port A write is selected by
CSA, W/RA, and ENA and MBA HIGH. A LOW-to-HIGH transition on CLKB
writes B0-B35 data to the mail2 register when a port B write is selected by
CSB, W/RB, and ENB and MBB is HIGH. Writing data to a mail register sets
the corresponding flag (MBF1 or MBF2) LOW. Attempted writes to a mail
register are ignored while the mail flag is LOW.
When a port's data outputs are active, the data on the bus comes from
the FIFO output register when the port Mailbox select input (MBA, MBB) is
LOW and from the mail register when the port mailbox select input is HIGH.
The Mail1 register Flag (MBF1) is set HIGH by a LOW-to-HIGH transition
on CLKB when a port B read is selected by CSB, W/RB, and ENB and MBB
is HIGH. The Mail2 register Flag (MBF2) is set HIGH by a LOW-to-HIGH
transition on CLKA when port A read is selected by CSA, W/RA, and ENA
and MBA is HIGH. The data in a mail register remains intact after it is read
and changes only when new data is written to the register. Mail register and
Mail Register Flag timing can be found in Figure 15 and Figure 16.
PARITY CHECKING
The port A inputs (A0-A35) and port B inputs (B0-B35) each have four
parity trees to check the parity of incoming (or outgoing) data. A parity failure
on one or more bytes of the input bus is reported by a LOW level on the port
Parity Error Flag (PEFA, PEFB). Odd or even parity checking can be
selected, and the Parity Error Fags can be ignored if this feature is not
desired.
Parity status is checked on each input bus according to the level of the
Odd/Even parity (ODD/EVEN) select input. A parity error on one or more
bytes of a port is reported by a LOW level on the corresponding port Parity Error
Flag (PEFA, PEFB) output. Port A bytes are arranged as A0-A8, A9-A17, A18-
COMMERCIAL TEMPERATURE RANGE
A26, and A27-A35 with the most significant bit of each byte used as the parity
bit. Port B bytes are arranged as B0-B8, B9-B17, B18-B26, and B27-B35, with
the most significant bit of each byte used as the parity bit. When odd/even parity
is selected, a port Parity Error Flag (PEFA, PEFB) is LOW if any byte on the
port has an odd/even number of LOW levels applied to the bits.
The four parity trees used to check the A0-A35 inputs are shared by the
mail2 register when parity generation is selected for port A reads (PGA = HIGH).
When a port A read from the mail2 register with parity generation is selected with
W/RA LOW, CSA LOW, ENA HIGH, MBA HIGH, and PGA HIGH, the port A
Parity Error Flag (PEFA) is held HIGH regardless of the levels applied to the
A0-A35 inputs. Likewise, the parity trees used to check the B0-B35 inputs are
shared by the mail1 register when parity generation is selected for port B reads
(PGB = HIGH). When a port B read from the mail1 register with parity generation
is selected with W/RB LOW, CSB LOW, ENB HIGH, MBB HIGH, and PGB HIGH,
the port B Parity Error Flag (PEFB) is held HIGH regardless of the levels applied
to the B0-B35 inputs (see Figure 17 and Figure 18).
PARITY GENERATION
A HIGH level on the port A Parity Generate select (PGA) or port B
Parity Generate select (PGB) enables the IDT72V3612 to generate parity
bits for port reads from a FIFO or mailbox register. Port A bytes are arranged
as A0-A8, A9-A17, A18-26, and A27-A35, with the most significant bit of
each byte used as the parity bit. Port B bytes are arranged as B0-B8, B9B17, B18-B26, and B27-B35, with the most significant bit of each byte used
as the parity bit. A write to a FIFO or mail register stores the levels applied
to all thirty-six inputs regardless of the state of the Parity Generate select
(PGA, PGB) inputs. When data is read from a port with parity generation
selected, the lower eight bits of each byte are used to generate a parity bit
according to the level on the ODD/EVEN select. The generated parity bits
are substituted for the levels originally written to the most significant bits of
each byte as the word is read to the data outputs.
Parity bits for FIFO data are generated after the data is read from
SRAM and before the data is written to the output register. Therefore, the
port A Parity Generate select (PGA) and Odd/Even parity select (ODD/
EVEN) have setup and hold time constraints to the port A Clock (CLKA) and
the port B Parity Generate select (PGB) and ODD/EVEN have setup and
hold-time constraints to the port B Clock (CLKB). These timing constraints
only apply for a rising clock edge used to read a new word to the FIFO output
register.
The circuit used to generate parity for the mail1 data is shared by the
port B bus (B0-B35) to check parity and the circuit used to generate parity
for the mail2 data is shared by the port A bus (A0-A35) to check parity. The
shared parity trees of a port are used to generate parity bits for the data in
a mail register when the port Write/Read select (W/RA, W/RB) input is LOW,
the port Mail select (MBA, MBB) input is HIGH, Chip Select (CSA, CSB) is
LOW, Enable (ENA, ENB) is HIGH, and port Parity Generate select (PGA,
PGB) is HIGH. Generating parity for mail register data does not change the
contents of the register (see Figure 19 and Figure 20).
12
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKA
tRSTH
CLKB
tRSTS
tFSS
tFSH
RST
0,1
FS1,FS0
tWFF
tWFF
FFA
tREF
EFA
tWFF
tWFF
FFB
tREF
EFB
tPAE
AEA
tPAF
AFA
MBF1,
MBF2
tRSF
tPAE
AEB
tPAF
AFB
4659 drw 05
Figure 2. Device Reset and Loading the X Register with the Value of Eight
13
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
CLKA
FFA HIGH
tENS1
tENH1
tENS1
tENH1
tENS3
tENH3
tENS2
tENH2
CSA
W/RA
MBA
tENS2
tENH2
tENS2
tENH2
ENA
tDS
tDH
W1(1)
A0 - A35
ODD/
EVEN
W2(1)
tPDPE
tPDPE
Valid
PEFA
No Operation
Valid
4659 drw 06
NOTE:
1. Written to FIFO1.
Figure 3. Port A Write Cycle Timing for FIFO1
tCLK
tCLKH
tCLKL
CLKB
FFB HIGH
tENS1
tENH1
tENS1
tENH1
tENS3
tENH3
tENS2
tENH2
CSB
W/RB
MBB
tENS2
tENH2
tENS2
tENH2
ENB
tDS
B0 - B35
ODD/
EVEN
PEFB
tDH
W1(1)
W2(1)
tPDPE
Valid
No Operation
tPDPE
Valid
4659 drw 07
NOTE:
1. Written to FIFO2.
Figure 4. Port B Write Cycle Timing for FIFO2
14
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
CLKB
EFB
HIGH
CSB
W/RB
tENS2
MBB
tENH2
tENS2
tENH2
ENB
tMDV
tEN
B0 - B35
tA
Previous Data (1)
tPGH
tPGS
PGB,
ODD/
EVEN
tA
Word 1(1)
tPGS
tENS2
tENH2
No Operation
tDIS
Word 2 (1)
tPGH
4659 drw 08
NOTE:
1. Read from FIFO1.
Figure 5. Port B Read Cycle Timing for FIFO1
tCLK
tCLKH
tCLKL
CLKA
EFA HIGH
CSA
W/RA
tENS2
MBA
tENH2
tENS2
tENH2
tENS2
tENH2
ENA
A0 - A35
PGA,
ODD/
EVEN
tEN
tMDV
tA
Previous Data (1)
tPGH
tPGS
tA
Word 1(1)
tPGS
No Operation
tDIS
Word 2 (1)
tPGH
4659 drw 09
NOTE:
1. Read from FIFO2.
Figure 6. Port A Read Cycle Timing for FIFO2
15
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH tCLKL
CLKA
CSA LOW
W/RA HIGH
tENS3
tENH3
tENS2
tENH2
MBA
ENA
FFA HIGH
tDS
tDH
W1
A0 - A35
(1)
tSKEW1
CLKB
EFB
tCLK
tCLKH tCLKL
1
2
tREF
tREF
FIFO1 Empty
CSB LOW
W/RB LOW
MBB LOW
tENS2
tENH2
ENB
tA
W1
B0 -B35
4659 drw 10
NOTE:
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for EFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA edge and
rising CLKB edge is less than tSKEW1, then the transition of EFB HIGH may occur one CLKB cycle later than shown.
Figure 7. EFB Flag Timing and First Data Read when FIFO1 is Empty
16
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH tCLKL
CLKB
CSB
LOW
W/RB HIGH
tENS3
tENH3
tENS2
tENH2
MBB
ENB
FFB
HIGH
tDS
tDH
W1
B0 - B35
(1)
tSKEW1
CLKA
EFA
FIFO2 Empty
CSA
LOW
W/RA
LOW
MBA
LOW
tCLK
tCLKH tCLKL
1
2
tREF
tENS2
tREF
tENH2
ENA
tA
A0 -A35
W1
4659 drw 11
NOTE:
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for EFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and
rising CLKA edge is less than tSKEW1, then the transition of EFA HIGH may occur one CLKA cycle later than shown.
Figure 8. EFA Flag Timing and First Data Read when FIFO2 is Empty
17
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
tCLKH
tCLK
COMMERCIAL TEMPERATURE RANGE
tCLKL
CLKB
CSB
LOW
W/RB
LOW
MBB
LOW
tENS2
tENH2
ENB
EFB
B0 - B35
HIGH
tA
Previous Word in FIFO1 Output Register
tSKEW1
CLKA
Next Word From FIFO1
(1)
tCLKH
1
tCLK
tCLKL
2
tWFF
tWFF
FFA
FIFO1 Full
CSA
LOW
W/RA
HIGH
tENS3
tENH3
tENS2
tENH2
MBA
ENA
tDH
tDS
A0 - A35
To FIFO1
4659 drw 12
NOTE:
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for FFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and
rising CLKA edge is less than tSKEW1, then FFA may transition HIGH one CLKA cycle later than shown.
Figure 9. FFA Flag Timing and First Available Write when FIFO1 is Full.
18
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
CLKA
CSA
LOW
W/RA
LOW
MBA
LOW
tENS2
tENH2
ENA
EFA
A0 - A35
HIGH
tA
Previous Word in FIFO2 Output Register
Next Word From FIFO2
tSKEW1(1)
CLKB
tCLKH
1
tCLK
tCLKL
2
tWFF
tWFF
FFB
FIFO2 Full
CSB
LOW
W/RB
HIGH
tENS3
tENH3
tENS2
tENH2
MBB
ENB
tDH
tDS
B0 - B35
To FIFO2
4659 drw 13
NOTE:
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for FFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA edge and
rising CLKB edge is less than tSKEW1, then FFB may transition HIGH one CLKB cycle later than shown.
Figure 10. FFB Flag Timing and First Available Write when FIFO2 is Full
CLKA
tENS2
tENH2
ENA
tSKEW2
CLKB
(1)
1
2
tPAE
AEB
X Words in FIFO1
tPAE
(X+1) Words in FIFO1
tENS2
tENH2
ENB
4659 drw 14
NOTES:
1. tSKEW2 is the minimum time between a rising CLKA edge and a rising CLKB edge for AEB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA edge and
rising CLKB edge is less than tSKEW2, then AEB may transition HIGH one CLKB cycle later than shown.
2. FIFO1 Write (CSA = LOW, W/RA = HIGH, MBA = LOW), FIFO1 read (CSB = LOW, W/RB = LOW, MBB = LOW).
Figure 11. Timing for AEB when FIFO1 is Almost Empty
19
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKB
tENS2
tENH2
ENB
(1)
tSKEW2
1
CLKA
2
tPAE
tPAE
AEA
X Words in FIFO2
(X+1) Words in FIFO2
tENS2
tENH2
ENA
4659 drw 15
NOTES:
1. tSKEW2 is the minimum time between a rising CLKB edge and a rising CLKA edge for AEA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and
rising CLKA edge is less than tSKEW2, then AEA may transition HIGH one CLKA cycle later than shown.
2. FIFO2 Write (CSB = LOW, W/RB = HIGH, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW).
Figure 12. Timing for AEA when FIFO2 is Almost Empty
tSKEW2
(1)
1
CLKA
tENS2
2
tENH2
ENA
tPAF
AFA
tPAF
(64-X) Words in FIFO1
[64-(X+1)] Words in FIFO1
CLKB
tENS2
tENH2
ENB
4659 drw 16
NOTES:
1. tSKEW2 is the minimum time between a rising CLKA edge and a rising CLKB edge for AFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKA edge and
rising CLKB edge is less than tSKEW2, then AFA may transition HIGH one CLKA cycle later than shown.
2. FIFO1 Write (CSA = LOW, W/RA = HIGH, MBA = LOW), FIFO1 read (CSB = LOW, W/RB = LOW, MBB = LOW).
Figure 13. Timing for AFA when FIFO1 is Almost Full
tSKEW2
(1)
1
CLKB
tENS2
2
tENH2
ENB
AFB
tPAF
tPAF
[64-(X+1)] Words in FIFO2
(64-X) Words in FIFO2
CLKA
tENS2
tENH2
ENA
4659 drw 17
NOTES:
1. tSKEW2 is the minimum time between a rising CLKB edge and a rising CLKA edge for AFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKB edge and
rising CLKA edge is less than tSKEW2, then AFB may transition HIGH one CLKB cycle later than shown.
2. FIFO2 Write (CSB = LOW, W/RB = HIGH, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW).
Figure 14. Timing for AFB when FIFO2 is Almost Full
20
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKA
tENS1
tENH1
tENS1
tENH1
tENS1
tENH1
tENS1
tENH1
CSA
W/RA
MBA
ENA
tDS
W1
A0 - A35
tDH
CLKB
tPMF
tPMF
MBF1
CSB
W/RB
MBB
tENS2
tENH2
ENB
tEN
B0 - B35
tMDV
tPMR
tDIS
W1 (Remains valid in Mail1 Register after read)
FIFO1 Output Register
4659 drw 18
NOTE:
1. Port B parity generation off (PGB = LOW).
Figure 15. Timing for Mail1 Register and MBF1 Flag
21
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKB
tENS1
tENH1
tENS1
tENH1
tENS1
tENH1
tENS1
tENH1
CSB
W/RB
MBB
ENB
tDS
W1
B0 - B35
tDH
CLKA
tPMF
tPMF
MBF2
CSA
W/RA
MBA
tENS2
tENH2
ENA
tMDV
tEN
FIFO2 Output Register
A0 - A35
tPMR
tDIS
W1 (Remains valid in Mail2 Register after read)
4659 drw 19
NOTE:
1. Port A parity generation off (PGA = LOW).
Figure 16. Timing for Mail2 Register and MBF2 Flag
ODD/
EVEN
W/RA
MBA
PGA
tPOPE
PEFA
Valid
tPEPE
tPOPE
Valid
Valid
tPEPE
Valid
4659 drw 20
NOTE:
1. ENA is HIGH, and CSA is LOW.
Figure 17. ODD/EVEN W/RA, MBA, and PGA to PEFA Timing
22
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
ODD/
EVEN
W/RB
MBB
PGB
tPOPE
PEFB
Valid
tPEPE
tPOPE
Valid
Valid
tPEPE
Valid
4659 drw 21
NOTE:
1. ENB is HIGH, and CSB is LOW.
Figure 18. ODD/EVEN W/RB, MBB, and PGB to PEFB Timing
ODD/
EVEN
CSA
LOW
W/RA
MBA
PGA
tEN
tPEPB
tMDV
A8, A17,
A26, A35
tPOPB
Generated Parity
tPEPB
Generated Parity
Mail2
Data
Mail2 Data
4659 drw 22
NOTE:
1. ENA is HIGH.
Figure 19. Parity Generation Timing when Reading from Mail2 Register
ODD/
EVEN
CSB LOW
W/RB
MBB
PGB
tEN
B8, B17,
B26, B35
tPEPB
tMDV
tPOPB
Generated Parity
tPEPB
Generated Parity
Mail1
Data
Mail1 Data
4659 drw 23
NOTE:
1. ENB is HIGH.
Figure 20. Parity Generation Timing when Reading from Mail1 Register
23
IDT72V3612 3.3V, CMOS SyncBiFIFOTM
64 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PARAMETER MEASUREMENT INFORMATION
3.3V
330Ω
From Output
Under Test
30 pF
(1)
510Ω
LOAD CIRCUIT
3V
1.5 V
Timing
Input
GND
tS
GND
tW
3V
1.5 V
1.5 V
1.5 V
1.5 V
th
3V
Data,
Enable
Input
Low-Level
Input
GND
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
1.5 V
1.5 V
GND
VOLTAGE WAVEFORMS
PULSE DURATIONS
3V
Output
Enable
1.5 V
tPLZ
1.5 V
tPZL
GND
≈ 3V
Input
1.5 V
Low-Level
Output
VOL
tPZH
VOH
High-Level
Output
3V
High-Level
Input
1.5 V
tPHZ
3V
1.5 V
1.5 V
tPD
tPD
GND
VOH
In-Phase
Output
1.5 V
1.5 V
≈ OV
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
4659 drw 24
NOTE:
1. Includes probe and jig capacitance
Figure 21. Load Circuit and Voltage Waveforms
24
ORDERING INFORMATION
IDT
XXXXXX
Device Type
X
Power
XX
Speed
X
Package
X
Process/
Temperature
Range
BLANK
Commercial (0°C to +70°C)
PF
PQF
Thin Quad Flat Pack (TQFP, PN120-1)
Plastic Quad Flat Pack (PQFP, PQ132-1)
12
15
20
Commercial Only
L
Low Power
Clock Cycle Time (tCLK)
Speed in Nanoseconds
72V3612 64 x 36 x 2  3.3V SyncBiFIFO
4659 drw 25
NOTE:
1. Industrial temperature range is available by special order.
DATASHEET DOCUMENT HISTORY
07/10/2000
05/27/2003
pg. 1.
pg. 6.
CORPORATE HEADQUARTERS
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800-345-7015 or 408-727-6116
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www.idt.com
25
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408-330-1753
email: [email protected]
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