IDT IDT723634 Cmos syncbififo with bus-matching Datasheet

CMOS SyncBiFIFOTM WITH BUS-MATCHING
256 x 36 x 2,
512 x 36 x 2,
1,024 x 36 x 2
FEATURES:
•
•
•
•
•
•
•
Memory storage capacity:
IDT723624 – 256 x 36 x 2
IDT723634 – 512 x 36 x 2
IDT723644 – 1,024 x 36 x 2
Clock frequencies up to 67 MHz (10 ns access time)
Two independent clocked FIFOs buffering data in opposite
directions
Select IDT Standard timing (using EFA, EFB, FFA, and FFB flags
functions) or First Word Fall Through Timing (using ORA, ORB,
IRA, and IRB flag functions)
Programmable Almost-Empty and Almost-Full flags; each has
three default offsets (8, 16 and 64)
•
•
•
•
•
•
•
IDT723624
IDT723634
IDT723644
Serial or parallel programming of partial flags
Port B bus sizing of 36-bits (long word), 18-bits (word) and
9-bits (byte)
Big- or Little-Endian format for word and byte bus sizes
Master Reset clears data and configures FIFO, Partial Reset
clears data but retains configuration settings
Mailbox bypass registers for each FIFO
Free-running CLKA and CLKB may be asynchronous or coincident (simultaneous reading and writing of data on a single clock
edge is permitted)
Auto power down minimizes power dissipation
Available in space saving 128-pin Thin Quad Flatpack (TQFP)
Green parts available, see ordering information
FUNCTIONAL BLOCK DIAGRAM
MBF1
MRS1
PRS1
FIFO1,
Mail1
Reset
Logic
RAM ARRAY
36
36
256 x 36
512 x 36
1,024 x 36
Write
Pointer
Output
Register
Port-A
Control
Logic
Output BusMatching
Mail 1
Register
Input
Register
CLKA
CSA
W/RA
ENA
MBA
36
Read
Pointer
36
FFA/IRA
AFA
Status Flag
Logic
FIFO1
SPM
FS0/SD
FS1/SEN
A0-A35
Programmable Flag
Offset Registers
EFB/ORB
AEB
Timing
Mode
FWFT
B0-B35
10
FIFO2
EFA/ORA
AEA
FFB/IRB
AFB
Status Flag
Logic
256 x 36
512 x 36
1,024 x 36
36
Input
Register
Output
Register
RAM ARRAY
36
36
Write
Pointer
Input BusMatching
Read
Pointer
36
FIFO2,
Mail2
Reset
Logic
Port-B
Control
Logic
Mail 2
Register
MBF2
MRS2
PRS2
CLKB
CSB
W/RB
ENB
MBB
BE
BM
SIZE
3270 drw01
IDT and the IDT logo are registered trademark of Integrated Device Technology, Inc. SyncBiFIFO is a trademark of Integrated Device Technology, Inc.
COMMERCIAL TEMPERATURE RANGE
JUNE 2014
1
© 2014 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.
DSC-3270/5
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
DESCRIPTION:
COMMERCIAL TEMPERATURE RANGE
These devices are a synchronous (clocked) FIFO, meaning 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 IDT723624/723634/723644 is a monolithic, high-speed, lowpower, CMOS bidirectional synchronous (clocked) FIFO memory which
supports clock frequencies up to 67 MHz and has read access times as fast as
10 ns. Two independent 256/512/1,024 x 36 dual-port SRAM FIFOs on board
each chip buffer data in opposite directions. FIFO data on Port B can be input
and output in 36-bit, 18-bit, or 9-bit formats with a choice of Big- or Little-Endian
configurations.
CSA
FFA/IRA
EFA/ORA
PRS1
Vcc
AFA
AEA
MBF2
MBA
MRS1
FS0/SD
GND
GND
FS1/SEN
MRS2
MBB
MBF1
Vcc
AEB
AFB
EFB/ORB
FFB/IRB
GND
CSB
W/RB
ENB
PIN CONFIGURATION
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
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
29
30
31
32
33
34
35
36
37
38
A9
A8
A7
A6
GND
A5
A4
A3
SPM
Vcc
A2
A1
A0
GND
B0
B1
B2
B3
B4
B5
GND
B6
Vcc
B7
B8
B9
W/RA
ENA
CLKA
GND
A35
A34
A33
A32
Vcc
A31
A30
GND
A29
A28
A27
A26
A25
A24
A23
BE/FWFT
GND
A22
Vcc
A21
A20
A19
A18
GND
A17
A16
A15
A14
A13
Vcc
A12
GND
A11
A10
128
127
126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
108
107
106
105
104
103
INDEX
TQFP (PK128-1, order code: PF)
TOP VIEW
2
CLKB
PRS2
Vcc
B35
B34
B33
B32
GND
GND
B31
B30
B29
B28
B27
B26
Vcc
B25
B24
BM
GND
B23
B22
B21
B20
B19
B18
GND
B17
B16
SIZE
Vcc
B15
B14
B13
B12
GND
B11
B10
3270 drw02
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
whether or not the FIFO memory is empty. FF shows whether the memory is
full or not. The IR and OR functions are selected in the First Word Fall Through
mode. IR indicates whether or not the FIFO has available memory locations.
OR shows whether the FIFO has data available for reading or not. It marks the
presence of valid data on the outputs.
Each FIFO has a programmable Almost-Empty flag (AEA and AEB) and
a programmable Almost-Full flag (AFA and AFB). AEA and AEB indicate when
a selected number of words remain in the FIFO memory. AFA and AFB indicate
when the FIFO contains more than a selected number of words.
FFA/IRA, FFB/IRB, AFA and AFB are two-stage synchronized to the port
clock that writes data into its array. EFA/ORA, EFB/ORB, AEA and AEB are
two-stage synchronized to the port clock that reads data from its array.
Programmable offsets for AEA, AEB, AFA and AFB are loaded in parallel using
Port A or in serial via the SD input. The Serial Programming Mode pin (SPM)
makes this selection. Three default offset settings are also provided. The AEA
and AEB threshold can be set at 8, 16 or 64 locations from the empty boundary
and the AFA and AFB threshold can be set at 8, 16 or 64 locations from the full
boundary. All these choices are made using the FS0 and FS1 inputs during
Master Reset.
Two or more devices may be used in parallel to create wider data
paths. If, at any time, the FIFO is not actively performing a function, the chip
will automatically power down. During the power down state, supply current
consumption (ICC) is at a minimum. Initiating any operation (by activating
control inputs) will immediately take the device out of the power down state.
The IDT723624/723634/723644 are characterized for operation from
0°C to 70°C. Industrial temperature range (-40°C to +85°C) is available. They
are fabricated using high speed, submicron CMOS technology.
Communication between each port may bypass the FIFOs via two
mailbox registers. The mailbox register width matches the selected Port B bus
width. Each Mailbox register has a flag (MBF1 and MBF2) to signal when new
mail has been stored.
Two kinds of reset are available on these FIFOs: Master Reset and Partial
Reset. Master Reset initializes the read and write pointers to the first location
of the memory array, configures the FIFO for Big- or Little-Endian byte
arrangement and selects serial flag programming, parallel flag programming,
or one of three possible default flag offset settings, 8, 16 or 64. There are two
Master Reset pins, MRS1 and MRS2.
Partial Reset also sets the read and write pointers to the first location of the
memory. Unlike Master Reset, any settings existing prior to Partial Reset (i.e.,
programming method and partial flag default offsets) are retained. Partial Reset
is useful since it permits flushing of the FIFO memory without changing any
configuration settings. Each FIFO has its own, independent Partial Reset pin,
PRS1 and PRS2.
These devices have two modes of operation: In the IDT Standard mode,
the first word written to an empty FIFO is deposited into the memory array. A
read operation is required to access that word (along with all other words
residing in memory). In the First Word Fall Through mode (FWFT), the first
long-word (36-bit wide) written to an empty FIFO appears automatically on the
outputs, no read operation is required (nevertheless, accessing subsequent
words does necessitate a formal read request). The state of the BE/FWFT pin
during FIFO operation determines the mode in use.
Each FIFO has a combined Empty/Output Ready Flag (EFA/ORA and
EFB/ORB) and a combined Full/Input Ready Flag (FFA/IRA and FFB/IRB).
The EF and FF functions are selected in the IDT Standard mode. EF indicates
3
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
PIN DESCRIPTIONS
Symbol
Name
I/O
COMMERCIAL TEMPERATURE RANGE
Description
A0-A35
Port A Data
I/O
36-bit bidirectional data port for side A.
AEA
Port A AlmostEmpty Flag
O
Programmable Almost-Empty flag synchronized to CLKA. It is LOW when the number of words in FIFO2 is less
than or equal to the value in the Almost-Empty A Offset register, X2.
AEB
Port B AlmostEmpty Flag
O
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 Almost-Empty B Offset register, X1.
AFA
Port A AlmostFull Flag
O
Programmable Almost-Full flag synchronized to CLKA. It is LOW when the number of empty locations in FIFO1
is less than or equal to the value in the Almost-Full A Offset register, Y1.
AFB
Port B AlmostFull Flag
O
Programmable Almost-Full flag synchronized to CLKB. It is LOW when the number of empty locations in FIFO2
FIFO2 is less than or equal to the value in the Almost-Full B Offset register, Y2.
B0-B35
Port A Data
I/O
36-bit bidirectional data port for side B.
BE/FWFT
Big-Endian/
First Word
Fall Through
Select
I
This is a dual purpose pin. During Master Reset, a HIGH on BE will select Big Endian operation. In this case,
depending on the bus size, the most significant byte or word on Port A is read from Port B first (A-to-B data
flow) or written to Port B first (B-to-A data flow). A LOW on BE will select Little-Endian operation. In this case,
the least significant byte or word on Port A is read from Port B first (for A-to-B data flow) or written to Port B first
(B-to-A data flow). After Master Reset, this pin selects the timing mode. A HIGH on FWFT selects IDT
Standard mode, a LOW selects First Word Fall Through mode. Once the timing mode has been
selected, the level on FWFT must be static throughout device operation.
BM(1)
Bus-Match
Select
(Port B)
I
A HIGH on this pin enables either byte or word bus width on Port B, depending on the state of SIZE. A LOW
selects long word operation. BM works with SIZE and BE to select the bus size and endian arrangement for
Port B. The level of BM must be static throughout device operation.
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. FFA/IRA, EFA/ORA, AFA, and AEA are all synchronized to the LOW-to-HIGH transition of
CLKA.
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. FFB/IRB, EFB/ORB, AFB, and AEB are synchronized to the LOW-to-HIGH transition of
CLKB.
CSA
Port A Chip
Select
I
CSA must be LOW to enable to LOW-to-HIGH transition of CLKA to read or write 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 on Port B. The B0-B35
outputs are in the high-impedance state when CSB is HIGH.
EFA/ORA
Port A Empty/
Output Ready
Flag
O
This is a dual function pin. In the IDT Standard mode, the EFA function is selected. EFA indicates whether or
not the FIFO2 memory is empty. In the FWFT mode, the ORA function is selected. ORA indicates the presence
of valid data on A0-A35 outputs, available for reading. EFA/ORA is synchronized to the LOW-to-HIGH
transition of CLKA.
EFB/ORB
Port B Empty/
Output Ready
Flag
O
This is a dual function pin. In the IDT Standard mode, the EFB function is selected. EFB indicates whether or
not the FIFO1 memory is empty. In the FWFT mode, the ORB function is selected. ORB indicates the presence
of valid data on the B0-B35 outputs, available for reading. EFB/ORB is synchronized to the LOW-to-HIGH transition
of CLKB.
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/IRA
Port A Full/
Input Read
Flag
O
This is a dual function pin. In the IDT Standard mode, the FFA function is selected. FFA indicates whether or
not the FIFO1 memory is full. In the FWFT mode, the IRA function is selected. IRA indicates whether or not
there is space available for writing to the FIFO1 memory. FFA/IRA is synchronized to the LOW-to-HIGH
transition of CLKA.
FFB/IRB
Port B Full/
Input Ready
Flag
O
This is a dual function pin. In the IDT Standard mode, the FFB function is selected. FFB indicates whether or
not the FIFO2 memory is full. In the FWFT mode, the IRB function is selected. IRB indicates whether or not
there is space available for writing to the FIFO memory. FFB/IRB is synchronized to the LOW-to-HIGH transition
of CLKB.
4
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTIONS (CONTINUED)
Symbol
Name
I/O
Description
FS1/SEN Flag Offset
Select 1/
Serial Enable,
I
FS1/SEN and FS0/SD are dual-purpose inputs used for flag offset register programming. During Master Reset,
FS1/SEN and FS0/SD, together with SPM, select the flag offset programming method. Three offset register
programming methods are available: automatically load one of three preset values (8, 16, or 64), parallel load
from Port A, and serial load.
FS0/SD
Flag Offset
Select 0/
Serial Data
I
When serial load is selected for flag offset register programming, FS1/SEN is used as an enable synchronous to
the LOW-to-HIGH transition of CLKA. When FS1/SEN is LOW, a rising edge on CLKA load the bit present on
FS0/SD into the X and Y registers. The number of bit writes required to program the offset registers is 32 for the
723624, 36 for the 723634, and 40 for the 723644. The first bit write stores the Y1 register MSB and the last bit
write stores the X2 register LSB.
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 LOW. MBF1 is set HIGH by a LOW-to-HIGH transition of CLKB when
a Port B read is selected and MBB is HIGH. MBF1 is set HIGH following either a Master or Partial Reset of
FIFO1.
MBF2
Mail2 Register
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 LOW. MBF2 is set HIGH by a LOW-to-HIGH transition of CLKA when a
Port A read is selected and MBA is HIGH. MBF2 is set HIGH following either a Master or Partial Reset of FIFO2.
MRS1
FIFO1 Master
Reset
I
A LOW on this pin initializes the FIFO1 read and write pointers to the first location of memory and sets the Port B
output register to all zeroes. A LOW-to-HIGH transition on MRS1 selects the programming method (serial or parallel)
and one of three programmable flag default offsets for FIFO1 and FIFO2. It also configures Port B for bus size and
endian arrangement. Four LOW-to-HIGH transitions of CLKA and four LOW-to-HIGH transitions of CLKB must occur
while MRS1 is LOW.
MRS2
FIFO2 Master
Reset
I
A LOW on this pin initializes the FIFO2 read and write pointers to the first location of memory and sets the Port A
output register to all zeroes. A LOW-to-HIGH transition on MRS2 toggled simultaneously with MRS1, selects the
programming method (serial or parallel) and one of the programmable flag default offsets for FIFO2. Four LOWto-HIGH transitions of CLKA and four LOW-to-HIGH transitions of CLKB must occur while MRS2 is LOW.
PRS1
FIFO1 Partial
Reset
I
A LOW on this pin initializes the FIFO1 read and write pointers to the first location of memory and sets the Port B
output register to all zeroes. During Partial Reset, the currently selected bus size, endian arrangement, program
ming method (serial or parallel), and programmable flag settings are all retained.
PRS2
FIFO2 Partial
Reset
I
A LOW on this pin initializes the FIFO2 read and write pointers to the first location of memory and sets the Port A
output register to all zeroes. During Partial Reset, the currently selected bus size, endian arrangement, program
ming method (serial or parallel), and programmable flag settings are all retained.
SIZE(1)
Bus Size Select
I
A HIGH on this pin when BM is HIGH selects byte bus (9-bit) size on Port B. A LOW on this pin when BM is
HIGH selects word (18-bit) bus size. SIZE works with BM and BE to select the bus size and endian arrangement
for Port B. The level of SIZE must be static throughout device operation.
SPM(1)
Serial Programming Mode
I
A LOW on this pin selects serial programming of partial flag offsets. A HIGH on this pin selects parallel
programming or default offsets (8, 16, or 64).
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-to- HIGH 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 LOW selects a write operation and a HIGH selects a read operation on Port B for a LOW-to-HIGH transition of
CLKB. The B0-B35 outputs are in the HIGH impedance state when W/RB is LOW.
NOTE:
1. BM, SIZE and SPM are not TTL compatible. These inputs should be tied to GND or VCC.
5
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE
RANGE (Unless otherwise noted)(1)
Symbol
V CC
VI(2)
VO(2)
IIK
IOK
I OUT
I CC
T STG
Rating
Supply Voltage Range
Input Voltage Range
Output Voltage Range
Input Clamp Current (VI < 0 or VI > VCC)
Output Clamp Current (VO = < 0 or VO > VCC)
Continuous Output Current (VO = 0 to VCC)
Continuous Current Through VCC or GND
Storage Temperature Range
Commercial
–0.5 to 7
–0.5 to VCC+0.5
–0.5 to VCC+0.5
±20
±50
±50
±400
–65 to 150
Unit
V
V
V
mA
mA
mA
mA
°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
VCC
VIH
VIL
IOH
IOL
TA
Parameter
Supply Voltage (Commercial)
High-Level Input Voltage (Commercial)
Low-Level Input Voltage (Commercial)
High-Level Output Current (Commercial)
Low-Level Output Current (Commercial)
Operating Free-Air Temperature (Commercial)
Min. Typ.
4.5
5.0
2
—
—
—
—
—
—
—
0
—
Max.
5.5
—
0.8
–4
8
70
Unit
V
V
V
mA
mA
°C
ELECTRICAL CHARACTERISTICS OVER RECOMMENDED OPERATING
FREE-AIR TEMPERATURE RANGE (Unless otherwise noted)
(Commercial: VCC = 5V ± 10%, TA = 0°C to +70°C)
Symbol
VOH
VOL
ILI
ILO
ICC2(2)
ICC3(2)
CIN(3)
COUT(3)
Parameter
Output Logic "1" Voltage
Output Logic "0" Voltage
Input Leakage Current (any Input)
Output Leakage Current
Standby Current (with CLKA and CLKB running)
Standby Current (no clocks running)
Input Capacitance
Output Capacitance
Test Conditions
VCC = 4.5V,
VCC = 4.5V,
VCC = 5.5V,
VCC = 5.5V,
VCC = 5.5V,
VCC = 5.5V,
VI = 0,
VO = 0,
IOH = –4 mA
IOL = 8 mA
VI = VCC or 0
VO = VCC or 0
VI = VCC –0.2 V or 0
VI = VCC –0.2 V or 0
f = 1 MHz
f = 1 MHz
NOTES:
1. All typical values are at VCC = 5V, TA = 25°C.
2. For additional ICC information, see Figure 1, Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS).
3. Characterized values, not currently tested.
6
IDT723624
IDT723634
IDT723644
Commercial
tCLK= 15ns
Min.
Typ.(1)
Max.
2.4
—
—
—
—
—
—
—
—
—
—
—
—
—
4
8
—
0.5
±10
±10
8
1
—
—
Unit
V
V
μA
μA
mA
mA
pF
pF
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 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 a FIFO on the IDT723624/723634/723644 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 and the number
of IDT723624/723634/723644 inputs driven by TTL HIGH levels are 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 these FIFOs may be calculated by:
PT = VCC x [ICC(f) + (N x ΔICC x dc)] + Σ(CL x VCC2 X fo)
where:
N
ΔICC
dc
CL
fo
=
=
=
=
=
number of used outputs = 36-bit (long word), 18-bit (word) or 9-bit (byte) bus size
increase in power supply current for each input at a TTL HIGH level
duty cycle of inputs at a TTL HIGH level of 3.4 V
output capacitance load
switching frequency of an output
300
fdata = 1/2 fS
TA = 25°C
CL = 0pF
250
VCC = 5.5V
mA
150
ICC(f)
200
Supply Current
VCC = 5.0V
VCC = 4.5V
100
50
0
0
10
20
30
40
50
60
70
80
90
3270 drw03
fS ⎯ Clock Frequency ⎯ MHz
Figure 1. Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS)
7
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
TIMING REQUIREMENTS OVER RECOMMENDED RANGES OF SUPPLY
VOLTAGE AND OPERATING FREE-AIR TEMPERATURE
(Commercial: VCC = 5V ± 10%, TA = 0°C to +70°C)
Commercial
IDT723624L15
IDT723634L15
IDT723644L15
Symbol
Parameter
Min.
Max.
Unit
fS
Clock Frequency, CLKA or CLKB
—
66.7
MHz
tCLK
Clock Cycle Time, CLKA or CLKB
15
—
ns
tCLKH
Pulse Duration, CLKA or CLKB HIGH
6
—
ns
tCLKL
Pulse Duration, CLKA and CLKB LOW
6
—
ns
tDS
Setup Time, A0-A35 before CLKA↑ and B0-B35 before CLKB↑
4
—
ns
tENS1
Setup Time, CSA and W/RA before CLKA↑; CSB and W/RB before CLKB↑
4.5
—
ns
tENS2
Setup Time ENA and MBA before CLKA↑; ENB and MBB before CLKB↑
4.5
—
ns
tRSTS
Setup Time, MRS1, MRS2, PRS1, or PRS2 LOW before CLKA↑ or CLKB↑
5
—
ns
tFSS
Setup Time, FS0 and FS1 before MRS1 and MRS2 HIGH
7.5
—
ns
tBES
Setup Time, BE/FWFT before MRS1 and MRS2 HIGH
7.5
—
ns
tSPMS
Setup Time, SPM before MRS1 and MRS2 HIGH
7.5
—
ns
tSDS
Setup Time, FS0/SD before CLKA↑
4
—
ns
tSENS
Setup Time, FS1/SEN before CLKA↑
4
—
ns
tFWS
Setup Time, BE/FWFT before CLKA↑
0
—
ns
tDH
Hold Time, A0-A35 after CLKA↑ and B0-B35 after CLKB↑
1
—
ns
tENH
Hold Time, CSA, W/RA, ENA, and MBA after CLKA↑; CSB, W/RB, ENB, and MBB after CLKB↑
1
—
ns
tRSTH
Hold Time, MRS1, MRS2, PRS1 or PRS2 LOW after CLKA↑ or CLKB↑
4
—
ns
tFSH
Hold Time, FS0 and FS1 after MRS1 and MRS2 HIGH
2
—
ns
tBEH
Hold Time, BE/FWFT after MRS1 and MRS2 HIGH
2
—
ns
tSPMH
Hold Time, SPM after MRS1 and MRS2 HIGH
2
—
ns
tSDH
Hold Time, FS0/SD after CLKA↑
1
—
ns
tSENH
Hold Time, FS1/SEN HIGH after CLKA↑
1
—
ns
Hold Time, FS1/SEN HIGH after MRS1 and MRS2 HIGH
2
—
ns
tSPH
tSKEW1
(1)
(1)
(2)
Skew Time between CLKA↑ and CLKB↑ for EFA/ORA, EFB/ORB, FFA/IRA, and FFB/IRB
7.5
—
ns
(2,3)
Skew Time between CLKA↑ and CLKB↑ for AEA, AEB, AFA, and AFB
12
—
ns
tSKEW2
NOTES:
1. Requirement to count the clock edge as one of at least four needed to reset a FIFO.
2. 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.
3. Design simulated, not tested.
8
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
SWITCHING CHARACTERISTICS OVER RECOMMENDED RANGES OF SUPPLY
VOLTAGE AND OPERATING FREE-AIR TEMPERATURE, CL = 30PF
(Commercial: VCC = 5V ± 10%, TA = 0°C to +70°C)
Commercial
IDT723624L15
IDT723634L15
IDT723644L15
Symbol
tA
Parameter
Access Time, CLKA↑ to A0-A35 and CLKB↑ to B0-B35
Min.
2
Max.
10
Unit
ns
tWFF
Propagation Delay Time, CLKA↑ to FFA/IRA and CLKB↑ to FFB/IRB
2
8
ns
tREF
Propagation Delay Time, CLKA↑ to EFA/ORA and CLKB↑ to EFB/ORB
1
8
ns
tPAE
Propagation Delay Time, CLKA↑ to AEA and CLKB↑ to AEB
1
8
ns
tPAF
Propagation Delay Time, CLKA to AFA and CLKB↑ to AFB
1
8
ns
tPMF
Propagation Delay Time, CLKA↑ to MBF1 LOW or MBF2 HIGH and CLKB↑ to MBF2
LOW or MBF1 HIGH
0
8
ns
tPMR
Propagation Delay Time, CLKA↑ to B0-B35(1) and CLKB↑ to A0-A35(2)
2
10
ns
tMDV
Propagation Delay Time, MBA to A0-A35 valid and MBB to B0-B35 valid
2
10
ns
tRSF
Propagation Delay Time, MRS1 or PRS1 LOW to AEB LOW, AFA HIGH, and MBF1
HIGH and MRS2 or PRS2 LOW to AEA LOW, AFB HIGH, and MBF2 HIGH
1
15
ns
tEN
Enable Time, CSA or W/RA LOW to A0-A35 Active and CSB LOW and W/RB HIGH to
B0-B35 Active
2
10
ns
tDIS
Disable Time, CSA or W/RA HIGH to A0-A35 at high impedance and CSB HIGH or W/RB
LOW to B0-B35 at HIGH impedance
1
8
ns
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.
9
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
SIGNAL DESCRIPTION
COMMERCIAL TEMPERATURE RANGE
BIG-ENDIAN/FIRST WORD FALL THROUGH (BE/FWFT)
— ENDIAN SELECTION
This is a dual purpose pin. At the time of Master Reset, the BE select function
is active, permitting a choice of Big or Little-Endian byte arrangement for data
written to or read from Port B. This selection determines the order by which
bytes (or words) of data are transferred through this port. For the following
illustrations, assume that a byte (or word) bus size has been selected for Port
B. (Note that when Port B is configured for a long word size, the Big-Endian
function has no application and the BE input is a “don’t care”1.)
A HIGH on the BE/FWFT input when the Master Reset (MRS1 , MRS2)
inputs go from LOW to HIGH will select a Big-Endian arrangement. When data
is moving in the direction from Port A to Port B, the most significant byte (word)
of the long word written to Port A will be read from Port B first; the least significant
byte (word) of the long word written to Port A will be read from Port B last. When
data is moving in the direction from Port B to Port A, the byte (word) written to
Port B first will be read from Port A as the most significant byte (word) of the long
word; the byte (word) written to Port B last will be read from Port A as the least
significant byte (word) of the long word.
A LOW on the BE/FWFT input when the Master Reset (MRS1, MRS2)
inputs go from LOW to HIGH will select a Little-Endian arrangement. When data
is moving in the direction from Port A to Port B, the least significant byte (word)
of the long word written to Port A will be read from Port B first; the most significant
byte (word) of the long word written to Port A will be read from Port B last. When
data is moving in the direction from Port B to Port A, the byte (word) written to
Port B first will be read from Port A as the least significant byte (word) of the long
word; the byte (word) written to Port B last will be read from Port A as the most
significant byte (word) of the long word. Refer to Figure 2 for an illustration of
the BE function. See Figure 3 (Master Reset) for the Endian select timing
diagram.
MASTER RESET (MRS1, MRS2)
After power up, a Master Reset operation must be performed by providing
a LOW pulse to MRS1 and MRS2 simultaneously. Afterwards, each of the two
FIFO memories of the IDT723624/723634/723644 undergoes a complete
reset by taking its associated Master Reset (MRS1, MRS2) input LOW for at
least four Port A Clock (CLKA) and four Port B Clock (CLKB) LOW-to-HIGH
transitions. The Master Reset inputs can switch asynchronously to the clocks.
A Master Reset initializes the associated read and write pointers to the first
location of the memory and forces the Full/Input Ready flag (FFA/IRA, FFB/
IRB) LOW, the Empty/Output Ready flag (EFA/ORA, EFB/ORB) LOW, the
Almost-Empty flag (AEA, AEB) LOW, and forces the Almost-Full flag (AFA,
AFB) HIGH. A Master Reset also forces the Mailbox Flag (MBF1, MBF2) of
the parallel mailbox register HIGH. After a Master Reset, the FIFO’s Full/Input
Ready flag is set HIGH after two write clock cycles. Then the FIFO is ready
to be written to.
A LOW-to-HIGH transition on a FlFO1 Master Reset (MRS1) input latches
the value of the Big-Endian (BE) input for determining the order by which bytes
are transferred through Port B. It also latches the values of the Flag Select (FS0,
FS1) and Serial Programming Mode (SPM) inputs for choosing the AlmostFull and Almost-Empty offset programming method.
A LOW-to-HIGH transition on a FlFO2 Master Reset (MRS2) clears the
Flag Offset registers of FIFO2 (X2, Y2). A LOW-to-HIGH transition of the FIFO2
Master Reset (MRS2) together with the FIFO1 Master Reset (MRS1) input
latches the value of the Big-Endian (BE) input for the Port B and also latches
the values of the Flag Select (FS0, FS1) and Serial Programming Mode (SPM)
inputs for choosing the Almost-Full and Almost-Empty offset programming
method (for details see Table 1, Flag Programming, and the Programming
of the Almost-Empty and Almost-Full flags section). The relevant FIFO Master
Reset timing diagram can be found in Figure 3.
— TIMING MODE SELECTION
After Master Reset, the FWFT select function is active, permitting a choice
between two possible timing modes: IDT Standard mode or First Word Fall
Through (FWFT) mode. Once the Master Reset (MRS1, MRS2) input is HIGH,
a HIGH on the BE/FWFT input during the next LOW-to-HIGH transition of CLKA
(for FIFO1) and CLKB (for FIFO2) will select IDT Standard mode. This mode
uses the Empty Flag function (EFA, EFB) to indicate whether or not there are
any words present in the FIFO memory. It uses the Full Flag function (FFA,
FFB) to indicate whether or not the FIFO memory has any free space for writing.
In IDT Standard mode, every word read from the FIFO, including the first, must
be requested using a formal read operation. Refer to Figure 3 (Master Reset)
for a First Word Fall Through select timing diagram.
Once the Master Reset (MRS1, MRS2) input is HIGH, a LOW on the BE/
FWFT input during the next LOW-to-HIGH transition of CLKA (for FIFO1) and
CLKB (for FIFO2) will select FWFT mode. This mode uses the Output Ready
function (ORA, ORB) to indicate whether or not there is valid data at the data
outputs (A0-A35 or B0-B35). It also uses the Input Ready function (IRA, IRB)
to indicate whether or not the FIFO memory has any free space for writing. In
the FWFT mode, the first word written to an empty FIFO goes directly to data
outputs, no read request necessary. Subsequent words must be accessed by
PARTIAL RESET (PRS1, PRS2)
Each of the two FIFO memories of these devices undergoes a limited reset
by taking its associated Partial Reset (PRS1, PRS2) input LOW for at least four
Port A Clock (CLKA) and four Port B Clock (CLKB) LOW-to-HIGH transitions.
The Partial Reset inputs can switch asynchronously to the clocks. A Partial
Reset initializes the internal read and write pointers and forces the Full/Input
Ready flag (FFA/IRA, FFB/IRB) LOW, the Empty/Output Ready flag (EFA/
ORA, EFB/ORB) LOW, the Almost-Empty flag (AEA, AEB) LOW, and the
Almost-Full flag (AFA, AFB) HIGH. A Partial Reset also forces the Mailbox Flag
(MBF1, MBF2) of the parallel mailbox register HIGH. After a Partial Reset, the
FIFO’s Full/Input Ready flag is set HIGH after two write clock cycles. Then the
FIFO is ready to be written to.
Whatever flag offsets, programming method (parallel or serial), and timing
mode (FWFT or IDT Standard mode) are currently selected at the time a Partial
Reset is initiated, those settings will be remain unchanged upon completion of
the reset operation. A Partial Reset may be useful in the case where
reprogramming a FIFO following a Master Reset would be inconvenient. See
Figure 4 for the Partial Reset timing diagram.
NOTE:
1. Either a HIGH or LOW can be applied to a "don't care" input with no change to the logical operation of the FIFO. Nevertheless, inputs that are temporarily "don't care" (along with
unused inputs) must not be left open, rather they must be either HIGH or LOW.
10
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
performing a formal read operation. Refer to Figure 3 (Master Reset) for a First
Word Fall Through select timing diagram.
Following Master Reset, the level applied to the BE/FWFT input to choose
the desired timing mode must remain static throughout FIFO operation.
COMMERCIAL TEMPERATURE RANGE
the offset registers are (A7-A0), (A8-A0), or (A9-A0) for the IDT723624,
IDT723634, or IDT723644, respectively. The highest numbered input is used
as the most significant bit of the binary number in each case. Valid programming
values for the registers range from 1 to 252 for the IDT723624; 1 to 508 for the
IDT723634; and 1 to 1,020 for the IDT723644. After all the offset registers are
programmed from Port A, the Port B Full/Input Ready flag (FFB/IRB) is set
HIGH, and both FIFOs begin normal operation. Refer to Figure 5 for a timing
diagram illustration of parallel programming of the flag offset values.
PROGRAMMING THE ALMOST-EMPTY AND ALMOST-FULL FLAGS
Four registers in the IDT723624/723634/723644 are used to hold the offset
values for the Almost-Empty and Almost-Full flags. The Port B Almost-Empty
flag (AEB) Offset register is labeled X1 and the Port A Almost-Empty flag (AEA)
Offset register is labeled X2. The Port A Almost-Full flag (AFA) Offset register
is labeled Y1 and the Port B Almost-Full flag (AFB) Offset register is labeled Y2.
The index of each register name corresponds to its FIFO number. The offset
registers can be loaded with preset values during the reset of a FIFO,
programmed in parallel using the FIFO’s Port A data inputs, or programmed
in serial using the Serial Data (SD) input (see Table 1).
SPM, FS0/SD and FS1/SEN function the same way in both IDT Standard
and FWFT modes.
— SERIAL LOAD
To program the X1, X2, Y1, and Y2 registers serially, initiate a Master Reset
with SPM LOW, FS0/SD LOW and FS1/SEN HIGH during the LOW-to-HIGH
transition of MRS1 and MRS2. After this reset is complete, the X and Y register
values are loaded bit-wise through the FS0/SD input on each LOW-to-HIGH
transition of CLKA that the FS1/SEN input is LOW. There are 32-, 36-, or 40bit writes needed to complete the programming for the IDT723624, IDT723634,
or IDT723644, respectively. The four registers are written in the order Y1, X1,
Y2, and finally, X2. The first-bit write stores the most significant bit of the Y1
register and the last-bit write stores the least significant bit of the X2 register. Each
register value can be programmed from 1 to 508 (IDT723624), 1 to 1,020
(IDT723634), or 1 to 2,044 (IDT723644).
When the option to program the offset registers serially is chosen, the Port
A Full/Input Ready (FFA/IRA) flag remains LOW until all register bits are written.
FFA/IRA is set HIGH by the LOW-to-HIGH transition of CLKA after the last bit
is loaded to allow normal FIFO1 operation. The Port B Full/Input Ready (FFB/
IRB) flag also remains LOW throughout the serial programming process, until
all register bits are written. FFB/IRB is set HIGH by the LOW-to-HIGH transition
of CLKB after the last bit is loaded to allow normal FIFO2 operation.
See Figure 6 for Serial Programming of the Almost-Full Flag and AlmostEmpty Flag Offset Values (IDT Standard and FWFT Modes).
— PRESET VALUES
To load a FIFO’s Almost-Empty flag and Almost-Full flag Offset registers with
one of the three preset values listed in Table 1, the Serial Program Mode (SPM)
and at least one of the flag-select inputs must be HIGH during the LOW-to-HIGH
transition of its Master Reset input (MRS1, MRS2). For example, to load the
preset value of 64 into X1 and Y1, SPM, FS0 and FS1 must be HIGH when
FlFO1 reset (MRS1) returns HIGH. Flag-offset registers associated with FIFO2
are loaded with one of the preset values in the same way with FIFO2 Master
Reset (MRS2), toggled simultaneously with FIFO1 Master Reset (MRS1). For
relevant preset value loading timing diagram, see Figure 3.
— PARALLEL LOAD FROM PORT A
To program the X1, X2, Y1, and Y2 registers from Port A, perform a Master
Reset on both FlFOs simultaneously with SPM HIGH and FS0 and FS1 LOW
during the LOW-to-HIGH transition of MRS1 and MRS2. After this reset is
complete, the first four writes to FIFO1 do not store data in the RAM but load
the offset registers in the order Y1, X1, Y2, X2. The Port A data inputs used by
FIFO WRITE/READ OPERATION
The state of the Port A data (A0-A35) lines is controlled by Port A Chip Select
(CSA) and Port A Write/Read select (W/RA). The A0-A35 lines are in the High-
TABLE 1 — FLAG PROGRAMMING
SPM
FS1/SEN
H
H
H
FS0/SD
X1 AND Y1 REGlSTERS(1)
X2 AND Y2 REGlSTERS(2)
MRS1
MRS2
H
↑
X
64
X
H
H
↑
↑
64
64
H
H
L
↑
X
16
X
H
H
L
↑
↑
16
16
H
L
H
↑
X
8
X
H
L
H
↑
↑
8
8
H
L
L
↑
↑
Parallel programming via Port A
Parallel programming via Port A
L
H
L
↑
↑
Serial programming via SD
Serial programming via SD
L
H
H
↑
↑
Reserved
Reserved
L
L
H
↑
↑
Reserved
Reserved
L
L
L
↑
↑
Reserved
Reserved
NOTES:
1. X1 register holds the offset for AEB; Y1 register holds the offset for AFA.
2. X2 register holds the offset for AEA; Y2 register holds the offset for AFB.
11
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
impedance state when either CSA or W/RA is HIGH. The A0-A35 lines are
active outputs 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/IRA 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/ORA is HIGH (see Table 2). FIFO reads and
writes on Port A are independent of any concurrent Port B operation.
The Port B control signals are identical to those of Port A with the exception
that the Port B Write/Read select (W/RB) is the inverse of the Port A Write/Read
select (W/RA). The state of the Port B data (B0-B35) lines is controlled by the
Port B Chip Select (CSB) and Port B Write/Read select (W/RB). The B0-B35
lines are in the high-impedance state when either CSB is HIGH or W/RB is
LOW. The B0-B35 lines are active outputs when CSB is LOW and W/RB is
HIGH.
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 LOW, ENB is HIGH, MBB is
LOW, and FFB/IRB 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 HIGH, ENB
is HIGH, MBB is LOW, and EFB/ORB is HIGH (see Table 3). FIFO reads and
writes on Port B are independent of any concurrent Port A operation.
The setup and hold time constraints to the port clocks for the port Chip Selects
and Write/Read selects are only for enabling write and read operations and
are not related to high-impedance control of the data outputs. If a port enable
COMMERCIAL TEMPERATURE RANGE
is LOW during a clock cycle, the port’s Chip Select and Write/Read select may
change states during the setup and hold time window of the cycle.
When operating the FIFO in FWFT mode and the Output Ready flag is LOW,
the next word written is automatically sent to the FIFO’s output register by the
LOW-to-HIGH transition of the port clock that sets the Output Ready flag HIGH.
When the Output Ready flag is HIGH, subsequent data is clocked to the output
registers only when a read is selected using the port’s Chip Select, Write/Read
select, Enable, and Mailbox select.
When operating the FIFO in IDT Standard mode, the first word will cause
the Empty Flag to change state on the second LOW-to-HIGH transition of the
Read clock. The data word will not be automatically sent to the output register.
Instead, data residing in the FIFO’s memory array is clocked to the output
register only when a read is selected using the port’s Chip Select, Write/Read
select, Enable, and Mailbox select. Write and Read timing diagrams for Port
A can be found in Figure 7 and 14. Relevant Port B Write and Read cycle timing
diagrams together with Bus-Matching and Endian select operations can be
found in Figures 8 through 13.
SYNCHRONIZED FIFO FLAGS
Each FIFO is synchronized to its port clock through at least two flip-flop
stages. This is done to improve flag-signal reliability by reducing the probability
of metastable events when CLKA and CLKB operate asynchronously to one
another. EFA/ORA, AEA, FFA/IRA, and AFA are synchronized to CLKA.
TABLE 2 — PORT A ENABLE FUNCTION TABLE
CSA
W/RA
H
X
ENA
MBA
X
X
CLKA
X
Data A (A0-A35) I/O
PORT FUNCTION
High-Impedance
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
H
X
X
X
X
Data B (B0-B35) I/O
High-Impedance
PORT FUNCTION
None
L
L
L
X
X
Input
None
L
L
H
L
↑
Input
FIFO2 write
L
L
H
H
↑
Input
Mail2 write
L
H
L
L
X
Output
None
L
H
H
L
↑
Output
FIFO1 read
L
H
L
H
X
Output
None
L
H
H
H
↑
Output
Mail1 read (set MBF1 HIGH)
12
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
In FWFT mode, from the time a word is written to a FIFO, it can be shifted
to the FIFO output register in a minimum of three cycles of the Output Ready
flag synchronizing clock. Therefore, an Output Ready flag is LOW if a word in
memory is the next data to be sent to the FlFO output register and three cycles
of the port Clock that reads data from the FIFO have not elapsed since the time
the word was written. The Output Ready flag of the FIFO remains LOW until
the third LOW-to-HIGH transition of the synchronizing clock occurs, simultaneously forcing the Output Ready flag HIGH and shifting the word to the FIFO
output register.
In IDT Standard mode, from the time a word is written to a FIFO, the Empty
Flag will indicate the presence of data available for reading in a minimum of two
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 FlFO 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 remains LOW
until the second LOW-to-HIGH transition of the synchronizing clock occurs,
forcing the Empty Flag HIGH; only then can data be read.
A LOW-to-HIGH transition on an Empty/Output Ready flag synchronizing
clock begins the first synchronization cycle of a write if the clock transition occurs
EFB/ORB, AEB, FFB/IRB, and AFB are synchronized to CLKB. Tables 4 and
5 show the relationship of each port flag to FIFO1 and FIFO2.
EMPTY/OUTPUT READY FLAGS (EFA/ORA, EFB/ORB)
These are dual purpose flags. In the FWFT mode, the Output Ready (ORA,
ORB) function is selected. When the Output Ready flag is HIGH, new data is
present in the FIFO output register. When the Output Ready flag is LOW, the
previous data word is present in the FIFO output register and attempted FIFO
reads are ignored.
In the IDT Standard mode, the Empty Flag (EFA, EFB) function is selected.
When the Empty Flag is HIGH, data is available in the FIFO’s RAM memory
for reading to the output register. When the Empty Flag is LOW, the previous
data word is present in the FIFO output register and attempted FIFO reads are
ignored.
The Empty/Output Ready flag of a FIFO is synchronized to the port clock
that reads data from its array. For both the FWFT and IDT Standard modes,
the FIFO read pointer is incremented each time a new word is clocked to its
output register. The state machine that controls an Output Ready flag monitors
a write pointer and read pointer comparator that indicates when the FIFO
memory status is empty, empty+1, or empty+2.
TABLE 4 — FIFO1 FLAG OPERATION (IDT Standard and FWFT modes)
Synchronized
to CLKB
Number of Words in FIFO Memory(1,2)
IDT723624(3)
IDT723634(3)
IDT723644(3)
Synchronized
to CLKA
EFB/ORB
AEB
AFA
FFA/IRA
0
0
0
L
L
H
H
1 to X1
1 to X1
1 to X1
H
L
H
H
(X1+1) to [256-(Y1+1)]
(X1+1) to [512-(Y1+1)]
(X1+1) to [1,024-(Y1+1)]
H
H
H
H
(256-Y1) to 255
(512-Y1) to 511
(1,024-Y1) to 1,023
H
H
L
H
256
512
1,024
H
H
L
L
NOTES:
1. When a word loaded to an empty FIFO is shifted to the output register, its previous FIFO memory location is free.
2. Data in the output register does not count as a "word in FIFO memory". Since in FWFT mode, the first word written to an empty FIFO goes unrequested to the output register
(no read operation necessary), it is not included in the FIFO memory count.
3. X1 is the Almost-Empty offset for FIFO1 used by AEB. Y1 is the Almost-Full offset for FIFO1 used by AFA. Both X1 and Y1 are selected during a FIFO1 reset or port A programming.
4. The ORB and IRA functions are active during FWFT mode; the EFB and FFA functions are active in IDT Standard mode.
TABLE 5 — FIFO2 FLAG OPERATION (IDT Standard and FWFT modes)
Synchronized
to CLKA
Number of Words in FIFO Memory(1,2)
Synchronized
to CLKB
IDT723624(3)
IDT723634(3)
IDT723644(3)
EFA/ORA
AEA
AFB
FFB/IRB
0
0
0
L
L
H
H
1 to X2
1 to X2
1 to X2
H
L
H
H
(X2+1) to [256-(Y2+1)]
(X2+1) to [512-(Y2+1)]
(X2+1) to [1,024-(Y2+1)]
H
H
H
H
(256-Y2) to 255
(512-Y2) to 511
(1,024-Y2) to 1,023
H
H
L
H
256
512
1,024
H
H
L
L
NOTES:
1. When a word loaded to an empty FIFO is shifted to the output register, its previous FIFO memory location is free.
2. Data in the output register does not count as a "word in FIFO memory". Since in FWFT mode, the first word written to an empty FIFO goes unrequested to the output register
(no read operation necessary), it is not included in the FIFO memory count.
3. X2 is the Almost-Empty offset for FIFO2 used by AEA. Y2 is the Almost-Full offset for FIFO2 used by AFB. Both X2 and Y2 are selected during a FIFO2 reset or port A programming.
4. The ORA and IRB functions are active during FWFT mode; the EFA and FFB functions are active in IDT Standard mode.
13
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
at time tSKEW1 or greater after the write. Otherwise, the subsequent clock cycle
can be the first synchronization cycle (see Figures 15, 16, 17, and 18).
FULL/INPUT READY FLAGS (FFA/IRA, FFB/IRB)
This is a dual purpose flag. In FWFT mode, the Input Ready (IRA and IRB)
function is selected. In IDT Standard mode, the Full Flag (FFA and FFB)
function is selected. For both timing modes, when the Full/Input Ready flag is
HIGH, a memory location is free in the FIFO to receive new data. No memory
locations are free when the Full/Input Ready flag is LOW and attempted writes
to the FIFO are ignored.
The Full/Input Ready flag of a FlFO is synchronized to the port clock that
writes data to its array. For both FWFT and IDT Standard modes, each time
a word is written to a FIFO, its write pointer is incremented. The state machine
that controls a Full/Input Ready flag monitors a write pointer and read pointer
comparator that indicates when the FlFO memory status is full, full-1, or full-2.
From the time a word is read from a FIFO, its previous memory location is ready
to be written to in a minimum of two cycles of the Full/Input Ready flag
synchronizing clock. Therefore, an Full/Input Ready flag is LOW if less than
two cycles of the Full/Input Ready flag synchronizing clock have elapsed since
the next memory write location has been read. The second LOW-to-HIGH
transition on the Full/Input Ready flag synchronizing clock after the read sets
the Full/Input Ready flag HIGH.
A LOW-to-HIGH transition on a Full/Input Ready 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 Figures 19, 20, 21, and 22).
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 and read 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 contents of register X1 for AEB and
register X2 for AEA. These registers are loaded with preset values during a
FIFO reset, programmed from Port A, or programmed serially (see AlmostEmpty flag and Almost-Full flag offset programming section). An AlmostEmpty flag is LOW when its FIFO contains X or less words and is HIGH when
its FIFO contains (X+1) or more words. A data word present in the FIFO output
register has been read from memory.
Two LOW-to-HIGH transitions of the Almost-Empty flag synchronizing clock
are required after a FIFO write for its Almost-Empty flag to reflect the new level
of fill. Therefore, the Almost-Full flag of a FIFO containing (X+1) or more words
remains LOW if two cycles of its 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 its 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 may be the first
synchronization cycle. (See Figures 23 and 24).
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 contents of register Y1 for AFA and register Y2 for AFB. These
COMMERCIAL TEMPERATURE RANGE
registers are loaded with preset values during a FlFO reset, programmed from
Port A, or programmed serially (see Almost-Empty flag and Almost-Full flag
offset programming section). An Almost-Full flag is LOW when the number of
words in its FIFO is greater than or equal to (256-Y), (512-Y), or (1,024-Y)
for the IDT723624, IDT723634, or IDT723644 respectively. An Almost-Full
flag is HIGH when the number of words in its FIFO is less than or equal to [256(Y+1)], [512-(Y+1)], or [1,024-(Y+1)] for the IDT723624, IDT723634, or
IDT723644 respectively. Note that a data word present in the FIFO output
register has been read from memory.
Two LOW-to-HIGH transitions of the Almost-Full flag synchronizing clock
are required after a FIFO read for its Almost-Full flag to reflect the new level
of fill. Therefore, the Almost-Full flag of a FIFO containing [256/512/1,024(Y+1)] or less words remains LOW if two cycles of its synchronizing clock have
not elapsed since the read that reduced the number of words in memory to [256/
512/1,024-(Y+1)]. An Almost-Full flag is set HIGH by the second LOW-to-HIGH
transition of its synchronizing clock after the FIFO read that reduces the number
of words in memory to [256/512/1,024-(Y+1)]. A 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 [256/512/1,024-(Y+1)]. Otherwise, the subsequent
synchronizing clock cycle may be the first synchronization cycle (see Figures
25 and 26).
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. The usable width of both the Mail1 and Mail2
registers matches the selected bus size for Port B.
A LOW-to-HIGH transition on CLKA writes data to the Mail 1 Register when
a Port A write is selected by CSA, W/RA, and ENA with MBA HIGH. If the
selected Port B bus size is also 36 bits, then the usable width of the Mail1 register
employs data lines A0-A35. If the selected Port B bus size is 18 bits, then the
usable width of the Mail1 Register employs data lines A0-A17. (In this case,
A18-A35 are don’t care inputs.) If the selected Port B bus size is 9 bits, then
the usable width of the Mail1 Register employs data lines A0-A8. (In this case,
A9-A35 are don’t care inputs.)
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 with MBB
HIGH. If the selected Port B bus size is also 36 bits, then the usable width of
the Mail2 employs data lines B0-B35. If the selected Port B bus size is 18 bits,
then the usable width of the Mail2 Register employs data lines B0-B17. (In this
case, B18-B35 are don’t care inputs.) If the selected Port B bus size is 9 bits,
then the usable width of the Mail1 Register employs data lines B0-B8. (In this
case, B9-B35 are don’t care inputs.)
Writing data to a mail register sets its corresponding flag (MBF1 or MBF2)
LOW. Attempted writes to a mail register are ignored while the mail flag is LOW.
When data outputs of a port are active, the data on the bus comes from the
FIFO output register when the port Mailbox select input 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 with MBB
HIGH. For a 36-bit bus size, 36 bits of mailbox data are placed on B0-B35. For
an 18-bit bus size, 18 bits of mailbox data are placed on B0-B17. (In this case,
B18-B35 are indeterminate.) For a 9-bit bus size, 9 bits of mailbox data are
placed on B0-B8. (In this case, B9-B35 are indeterminate.)
14
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
data is read from the FIFO1 RAM and before data is written to the FIFO2 RAM.
These bus-matching operations are not available when transferring data via
mailbox registers. Furthermore, both the word- and byte-size bus selections
limit the width of the data bus that can be used for mail register operations. In
this case, only those byte lanes belonging to the selected word- or byte-size
bus can carry mailbox data. The remaining data outputs will be indeterminate.
The remaining data inputs will be don’t care inputs. For example, when a wordsize bus is selected, then mailbox data can be transmitted only between A0A17 and B0-B17. When a byte-size bus is selected, then mailbox data can be
transmitted only between A0-A8 and B0-B8. (See Figures 27 and 28).
The Mail2 Register Flag (MBF2) is set HIGH by a LOW-to-HIGH transition
on CLKA when a Port A read is selected by CSA, W/RA, and ENA with MBA
HIGH.
For a 36-bit bus size, 36 bits of mailbox data are placed on A0-A35. For
an 18-bit bus size, 18 bits of mailbox data are placed on A0-A17. (In this case,
A18-A35 are indeterminate.) For a 9-bit bus size, 9 bits of mailbox data are
placed on A0-A8. (In this case, A9-A35 are indeterminate.)
The data in a mail register remains intact after it is read and changes only
when new data is written to the register. The Endian select feature has no effect
on mailbox data. For mail register and Mail Register flag timing diagrams, see
Figure 27 and 28.
BUS-MATCHING FIFO1 READS
Data is read from the FIFO1 RAM in 36-bit long word increments. If a long
word bus size is implemented, the entire long word immediately shifts to the
FIFO1 output register. If byte or word size is implemented on Port B, only the
first one or two bytes appear on the selected portion of the FIFO1 output register,
with the rest of the long word stored in auxiliary registers. In this case, subsequent
FIFO1 reads output the rest of the long word to the FIFO1 output register in the
order shown by Figure 2.
When reading data from FIFO1 in byte or word format, the unused B0-B35
outputs are indeterminate.
BUS SIZING
The Port B bus can be configured in a 36-bit long word, 18-bit word, or
9-bit byte format for data read from FIFO1 or written to FIFO2. The levels
applied to the Port B Bus Size select (SIZE) and the Bus-Match select (BM)
determine the Port B bus size. These levels should be static throughout FIFO
operation. Both bus size selections are implemented at the completion of Master
Reset, by the time the Full/Input Ready flag is set HIGH, as shown in Figure
2.
Two different methods for sequencing data transfer are available for Port
B when the bus size selection is either byte- or word-size. They are referred
to as Big-Endian (most significant byte first) and Little-Endian (least significant
byte first). The level applied to the Big-Endian select (BE) input during the LOWto-HIGH transition of MRS1 and MRS2 selects the endian method that will be
active during FIFO operation. BE is a don’t care input when the bus size
selected for Port B is long word. The endian method is implemented at the
completion of Master Reset, by the time the Full/Input Ready flag is set HIGH,
as shown in Figure 2.
Only 36-bit long word data is written to or read from the two FIFO memories
on the IDT723624/723634/723644. Bus-matching operations are done after
BUS-MATCHING FIFO2 WRITES
Data is written to the FIFO2 RAM in 36-bit long word increments. Data written
to FIFO2 with a byte or word bus size stores the initial bytes or words in auxiliary
registers. The CLKB rising edge that writes the fourth byte or the second word
of long word to FIFO2 also stores the entire long word in the FIFO2 memory.
The bytes are arranged in the manner shown in Figure 2.
When writing data to FIFO2 in byte or word format, the unused B0-B35 inputs
are don't care inputs.
15
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
BYTE ORDER ON PORT A:
BE
BM
SIZE
X
L
X
COMMERCIAL TEMPERATURE RANGE
A35⎯A27
A26⎯A18
A17⎯A9
A8⎯A0
A
B
C
D
B35⎯B27
B26⎯B18
B17⎯B9
B8⎯B0
A
B
C
D
Write to FIFO1/
Read from FIFO2
Read from FIFO1/
Write to FIFO2
(a) LONG WORD SIZE
BYTE ORDER ON PORT B:
BE
BM
H
H
B35⎯B27
B26⎯B18
B17⎯B9
B8⎯B0
A
B
B17⎯B9
B8⎯B0
SIZE
L
B35⎯B27
B26⎯B18
C
D
1st: Read from FIFO1/
Write to FIFO2
2nd: Read from FIFO1/
Write to FIFO2
(b) WORD SIZE ⎯ BIG ENDIAN
B35⎯B27
BE
BM
SIZE
L
H
L
B26⎯B18
B17⎯B9
C
B35⎯B27
B26⎯B18
B17⎯B9
A
B8⎯B0
D
1st: Read from FIFO1/
Write to FIFO2
B8⎯B0
B
2nd: Read from FIFO1/
Write to FIFO2
(c) WORD SIZE ⎯ LITTLE-ENDIAN
B35⎯B27
BE
BM
SIZE
H
H
H
B26⎯B18
B17⎯B9
B8⎯B0
A
B35⎯B27
B26⎯B18
B17⎯B9
B8⎯B0
B
B35⎯B27
B26⎯B18
B17⎯B9
B26⎯B18
B17⎯B9
2nd: Read from FIFO1/
Write to FIFO2
B8⎯B0
C
B35⎯B27
1st: Read from FIFO1/
Write to FIFO2
3rd: Read from FIFO1/
Write to FIFO2
B8⎯B0
D
4th: Read from FIFO1/
Write to FIFO2
(d) BYTE SIZE ⎯ BIG-ENDIAN
B35⎯B27
BE
L
BM
H
B26⎯B18
B17⎯B9
SIZE
H
B8⎯B0
D
B35⎯B27
B26⎯B18
B17⎯B9
B8⎯B0
C
B35⎯B27
B26⎯B18
B17⎯B9
B26⎯B18
B17⎯B9
Figure 2. Bus Sizing
16
3rd: Read from FIFO1/
Write to FIFO2
B8⎯B0
A
(e) BYTE SIZE ⎯ LITTLE-ENDIAN
2nd: Read from FIFO1/
Write to FIFO2
B8⎯B0
B
B35⎯B27
1st: Read from FIFO1/
Write to FIFO2
4th: Read from FIFO1/
Write to FIFO2
3270 drw 04
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKA
CLKB
tRSTS
tRSTH
MRS1
tBEH
tBES
BE/FWFT
BE
tFWS
FWFT
tSPMS
tSPMH
tFSS
tFSH
SPM
FS1,FS0
0,1
tWFF
tWFF
FFA/IRA
tREF (3)
EFB/ORB
tRSF
AEB
tRSF
AFA
tRSF
MBF1
3270 drw05
NOTES:
1. FIFO2 (MRS2) Master Reset is performed in the same manner to load X2 and Y2 with a preset value. For FIFO2 Master Reset (MRS1) must toggle simultaneously with MRS2.
2. PRS1 must be HIGH during Master Reset.
3. If BE/FWFT is HIGH, then EFB/ORB will go LOW one CLKB cycle earlier than the case where BE/FWFT is LOW.
Figure 3. FIFO1 Master Reset and Loading X1 and Y1 with a Preset Value of Eight(1) (IDT Standard and FWFT Modes)
CLKA
CLKB
tRSTS
tRSTH
PRS1
tWFF
tWFF
FFA/IRA
tREF(3)
EFB/ORB
tRSF
AEB
tRSF
AFA
tRSF
MBF1
NOTES:
1. Partial Reset is performed in the same manner for FIFO2.
2. MRS1 must be HIGH during Partial Reset.
3. If BE/FWFT is HIGH, then EFB/ORB will go LOW one CLKB cycle earlier than in this case where BE/FWFT is LOW.
Figure 4. FIFO1 Partial Reset(1) (IDT Standard and FWFT Modes)
17
3270 drw06
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
CLKA
2
1
4
COMMERCIAL TEMPERATURE RANGE
MRS1,
MRS2
tFSS
tFSH
tFSS
tFSH
SPM
FS1,FS0
0,0
tWFF
FFA/IRA
tENS2
tSKEW1 (1)
tENH
ENA
tDH
tDS
A0-A35
AFA Offset
(Y1)
AEB Offset
(X1)
AFB Offset
(Y 2)
AEA Offset
(X 2)
CLKB
First Word to FIFO1
1
2
tWFF
FFB/IRB
3270 drw07
NOTES:
1. tSKEW1 is the minimum time between the rising CLKA edge and a rising CLKB edge for FFB/IRB to transition HIGH in the next cycle. If the time between the rising edge of CLKA
and rising edge of CLKB is less than tSKEW1, then FFB/IRB may transition HIGH one CLKB cycle later than shown.
2. CSA=LOW, W/RA=HIGH,MBA=LOW. It is not necessary to program offset register on consecutive clock cycles.
Figure 5. Parallel Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values after Reset (IDT Standard and FWFT Modes)
CLKA
4
MRS1,
MRS2
tFSS
tFSH
SPM
tWFF
tSKEW(1)
FFA/IRA
tFSS
tSPH
tSENS
tSENH
tSENS
tSENH
FS1/SEN
tSDS
tSDH
tSDS
tSDH
FS0/SD(3)
AFA Offset
(Y1) MSB
CLKB
AEA Offset
(X2) LSB
4
tWFF
FFB/IRB
3270 drw08
NOTES:
1. tSKEW1 is the minimum time between the rising CLKA edge and a rising CLKB edge for FFB/IRB to transition HIGH in the next cycle. If the time between the rising edge of CLKA
and rising edge of CLKB is less than tSKEW1, then FFB/IRB may transition HIGH one CLKB cycle later than shown.
2. It is not necessary to program offset register bits on consecutive clock cycles. FIFO write attempts are ignored until FFA/IRA and FFB/IRB is set HIGH.
3. Programmable offsets are written serially to the SD input in the order AFA offset (Y1), AEB offset (X1), AFB offset (Y2), and AEA offset (X2).
Figure 6. Serial Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values (IDT Standard and FWFT Modes)
18
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
CLKA
FFA/IRA
HIGH
tENS1
tENH
tENS1
tENH
CSA
W/RA
tENS2
tENH
tENS2
tENH
MBA
tENS2
tENS2
tENH
tENH
ENA
tDS
tDH
W1(1)
A0 - A35
W2 (1)
No Operation
3270 drw09
NOTE:
1. Written to FIFO1.
Figure 7. Port A Write Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)
tCLK
tCLKH
tCLKL
CLKB
FFB/IRB HIGH
tENS1
tENH
tENS1
tENH
tENS2
tENH
CSB
W/RB
MBB
tENS2
tENH
tENS2
tENH
tENS2
tENH
ENB
tDS
W1(1)
B0-B35
tDH
No Operation
W2 (1)
3270 drw10
NOTE:
1. Written to FIFO2.
DATA SIZE TABLE FOR LONG-WORD WRITES TO FIFO2
SIZE MODE(1)
DATA WRITTEN TO FIFO2
DATA READ FROM FIFO2
BM
SIZE
BE
B35-B27
B26-B18
B17-B9
B8-B0
A35-A27
A26-A18
A17-A9
A8-A0
L
X
X
A
B
C
D
A
B
C
D
NOTE:
1. BE is selected at Master Reset: BM and SIZE must be static throughout device operation.
Figure 8. Port B Long-Word Write Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)
19
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKB
FFB/IRB HIGH
tENS1
tENH
CSB
tENS1
W/RB
tENS2
tENH
tENS2
tENH
tENS2
tENH
tENS2
tENH
MBB
ENB
tDS
tDH
B0-B17
3270 drw11
DATA SIZE TABLE FOR WORD WRITES TO FIFO2
SIZE MODE(1)
WRITE NO.
BM
SIZE
BE
H
L
H
H
L
L
1
2
1
2
DATA WRITTEN TO FIFO2
DATA READ FROM FIFO2
B17-B9
B8-B0
A35-A27
A26-A18
A17-A9
A8-A0
A
C
C
A
B
D
D
B
A
B
C
D
A
B
C
D
NOTE:
1. BE is selected at Master Reset; BM and SIZE must be static throughout device operation.
Figure 9. Port B Word Write Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)
CLKB
FFB/IRB
HIGH
tENH
tENS1
CSB
tENS1
W/RB
tENS2
tENH
tENH
MBB
tENS2
tENH
tENS2
tENH
ENB
tDS
tDH
B0-B8
3270 drw12
DATA SIZE TABLE FOR BYTE WRITES TO FIFO2
SIZE MODE(1)
BM
SIZE
WRITE
NO.
BE
H
H
H
H
H
L
DATA WRITTEN
TO FIFO2
B8-B0
1
2
3
4
1
2
3
4
A
B
C
D
D
C
B
A
DATA READ FROM FIFO2
A35-A27
A26-A18
A17-A9
A8-A0
A
B
C
D
A
B
C
D
NOTE:
1. BE is selected at Master Reset; BM and SIZE must be static throughout device operation.
Figure 10. Port B Byte Write Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)
20
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
tCLK
tCLKH
COMMERCIAL TEMPERATURE RANGE
tCLKL
CLKB
EFB/ORB
HIGH
CSB
W/RB
MBB
tENS2
tENS2
tENH
tENH
tENH
tENS2
ENB
tMDV
B0-B35
(Standard Mode)
OR
tEN
B0-B35
tMDV
W1(1)
tDIS
W2 (1)
tDIS
tA
tA
W3 (1)
W2 (1)
W1(1)
(FWFT Mode)
No Operation
tA
tA
Previous Data
tEN
3270 drw13
NOTE:
1. Read From FIFO1.
DATA SIZE TABLE FOR FIFO LONG-WORD READS FROM FIFO1
SIZE MODE(1)
DATA WRITTEN TO FIFO1
DATA READ FROM FIFO1
BM
SIZE
BE
A35-A27
A26-A18
A17-A9
A8-A0
B35-B27
B26-B18
B17-B9
B8-B0
L
X
X
A
B
C
D
A
B
C
D
NOTE:
1. BE is selected at Master Reset; BM and SIZE must be static throughout device operation.
Figure 11. Port B Long-Word Read Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)
CLKB
EFB/ORB
HIGH
CSB
W/RB
MBB
tENS2
tENH
ENB
tMDV
tEN
B0-B17
(Standard Mode)
OR
tEN
B0-B17
tMDV
Read 1
tDIS
Read 2
tDIS
tA
tA
Read 1
(FWFT Mode)
No Operation
tA
tA
Previous Data
Read 2
Read 3
3270 drw14
NOTE:
1. Unused word B18-B35 are indeterminate for word size reads.
DATA SIZE TABLE FOR WORD READS FROM FIFO1
SIZE MODE(1)
DATA WRITTEN TO FIFO1
BM
SIZE
BE
A35-A27
H
L
H
A
H
L
L
A
A26-A18
READ NO.
A17-A9
A8-A0
B
C
D
B
C
D
B17-B9
B8-B0
1
2
A
C
B
D
1
2
C
A
D
B
NOTE:
1. BE is selected at Master Reset; BM and SIZE must be static throughout device operation .
Figure 12. Port-B Word Read Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)
21
DATA READ FROM FIFO1
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKB
EFB/ORB HIGH
CSB
W/RB
MBB
tENS2
tENH
ENB
tEN
B0-B8
(Standard Mode)
tMDV
tA
Previous Data
tA
Read 1
tA
Read 2
tA
Read 3
tA
Read 1
tA
Read 2
tA
Read 3
tA
Read 4
tMDV
OR
tEN
B0-B8
(FWFT Mode)
No Operation
tDIS
Read 4
tDIS
Read 5
3270 drw15
NOTE:
1. Unused bytes B9-B17, B18-B26, and B27-B35 are indeterminate.
DATA SIZE TABLE FOR BYTE READS FROM FIFO1
SIZE MODE(1)
BM
DATA WRITTEN TO FIFO1
SIZE
H
BE
H
H
A35-A27
H
H
A26-A18
A
L
A17-A9
B
A
READ NO.
A8-A0
C
B
DATA READ
FROM FIFO1
B8-B0
D
C
1
A
2
B
3
C
4
D
1
D
D
2
C
3
B
4
A
NOTE:
1. BE is selected at Master Reset; BM and SIZE must be static throughout device operation.
Figure 13. Port-B Byte Read Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)
tCLKH
tCLK
tCLKL
CLKA
EFA/ORA
HIGH
CSA
W/RA
MBA
tENS2
tENS2
tENH
tENH
tENH
tENS2
ENA
tMDV
A0-A35
tEN
(Standard Mode)
OR
A0-A35
(FWFT Mode)
tMDV
tEN
tA
tA
Previous Data
tDIS
tA
(1)
W2
tDIS
W2 (1)
W1(1)
tA
W1
No Operation
(1)
W3(1)
3270 drw16
NOTE:
1. Read From FIFO2.
Figure 14. Port-A Read Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)
22
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
CLKA
CSA
LOW
WRA
HIGH
tENS2
tENH
tENS2
tENH
tDS
tDH
MBA
ENA
IRA
HIGH
A0-A35
W1
tSKEW1
CLKB
(1)
tCLKH
1
tCLK
tCLKL
2
3
tREF
ORB
FIFO1 Empty
CSB
LOW
W/RB
HIGH
MBB
LOW
tREF
tENS2
tENH
ENB
tA
B0-B35
Old Data in FIFO1 Output Register
W1
3270 drw17
NOTES:
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for ORB to transition HIGH and to clock the next word to the FIFO1 output register in three CLKB cycles.
If the time between the rising CLKA edge and rising CLKB edge is less than tSKEW1, then the transition of ORB HIGH and load of the first word to the output register may occur one CLKB
cycle later than shown.
2. If Port B size is word or byte, ORB is set LOW by the last word or byte read from FIFO1, respectively.
Figure 15. ORB Flag Timing and First Data Word Fall Through when FIFO1 is Empty (FWFT Mode)
23
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH tCLKL
CLKA
CSA
LOW
WRA
HIGH
tENS2
tENH
tENS2
tENH
tDS
tDH
MBA
ENA
FFA
HIGH
W1
A0-A35
(1)
tSKEW1
CLKB
tCLK
tCLKH tCLKL
1
2
tREF
EFB
FIFO1 Empty
CSB
LOW
W/RB
HIGH
MBB
LOW
tENS2
tREF
tENH
ENB
tA
B0-B35
W1
3270 drw18
NOTES:
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.
2. If Port B size is word or byte, EFB is set LOW by the last word or byte read from FIFO1, respectively.
Figure 16. EFB Flag Timing and First Data Read Fall Through when FIFO1 is Empty (IDT Standard Mode)
24
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
CLKB
CSB
LOW
W/RB
LOW
tENS2
tENH
tENS2
tENH
MBB
ENB
IRB
HIGH
tDH
tDS
W1
B0-B35
(1)
tSKEW1
CLKA
tCLKH
1
tCLK
tCLKL
2
3
tREF
ORA
FIFO2 Empty
CSA
LOW
W/RA
LOW
MBA
LOW
tENS2
tREF
tENH
ENA
tA
A0-A35
Old Data in FIFO2 Output Register
W1
3270 drw19
NOTES:
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for ORA to transition HIGH and to clock the next word to the FIFO2 output register in three CLKA cycles.
If the time between the CLKB edge and the rising CLKA edge is less than tSKEW1, then the transition of ORA HIGH and load of the first word to the output register may occur one CLKA
cycle later than shown.
2. If Port B size is word or byte, tSKEW1 is referenced to the rising CLKB edge that writes the last word or byte of the long word, respectively.
Figure 17. ORA Flag Timing and First Data Word Fall through when FIFO2 is Empty (FWFT Mode)
25
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH tCLKL
CLKB
CSB
LOW
W/RB
LOW
tENS2
tENH
tENS2
tENH
MBB
ENB
FFB
HIGH
tDH
tDS
W1
B0-B35
(1)
tSKEW1
CLKA
tCLK
tCLKH tCLKL
1
2
tREF
EFA
FIFO2 Empty
CSA
LOW
W/RA
LOW
MBA
LOW
tENS2
tREF
tENH
ENA
tA
A0-A35
W1
3270 drw20
NOTES:
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.
2. If Port B size is word or byte, tSKEW1 is referenced to the rising CLKB edge that writes the last word or byte of the long word, respectively.
Figure 18. EFA Flag Timing and First Data Read when FIFO2 is Empty (IDT Standard Mode)
26
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
tCLKH
tCLK
COMMERCIAL TEMPERATURE RANGE
tCLKL
CLKB
CSB
LOW
W/RB
MBB
HIGH
LOW
tENS2
tENH
ENB
ORB
B0-B35
HIGH
tA
Previous Word in FIFO1 Output Register
Next Word From FIFO1
tSKEW1 (1)
tCLKH
tCLK
tCLKL
1
CLKA
2
tWFF
tWFF
IRA
FIFO1 Full
CSA
LOW
W/RA
HIGH
tENS2
tENH
tENS2
tENH
MBA
ENA
tDS
tDH
Write
A0-A35
To FIFO1
3270 drw21
NOTES:
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for IRA 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 IRA may transition HIGH one CLKA cycle later than shown.
2. If Port B size is word or byte, tSKEW1 is referenced to the rising CLKB edge that reads the last word or byte write of the long word, respectively.
Figure 19. IRA Flag Timing and First Available Write when FIFO1 is Full (FWFT Mode)
27
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
tCLKH
tCLK
COMMERCIAL TEMPERATURE RANGE
tCLKL
CLKB
CSB
LOW
W/RB
MBB
HIGH
LOW
tENS2
tENH
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
tENS2
tENH
tENS2
tENH
MBA
ENA
tDH
tDS
Write
A0-A35
To FIFO1
3270 drw22
NOTES:
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.
2. If Port B size is word or byte, tSKEW1 is referenced from the rising CLKB edge that reads the last word or byte of the long word, respectively.
Figure 20. FFA Flag Timing and First Available Write when FIFO1 is Full (IDT Standard Mode)
28
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
tCLKH
CLKA
CSA
W/RA
LOW
MBA
LOW
tCLK
COMMERCIAL TEMPERATURE RANGE
tCLKL
LOW
tENS2
tENH
ENA
ORA
A0-A35
HIGH
tA
Previous Word in FIFO2 Output Register
Next Word From FIFO2
(1)
tSKEW1
CLKB
tCLKH
1
tCLK
tCLKL
2
tWFF
tWFF
IRB
FIFO2 FULL
CSB
LOW
W/RB
LOW
tENS2
tENH
tENS2
tENH
MBB
ENB
tDS
tDH
Write
To FIFO2
B0-B35
3270 drw23
NOTES:
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for IRB 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 IRB may transition HIGH one CLKB cycle later than shown.
2. If Port B size is word or byte, IRB is set LOW by the last word or byte write of the long word, respectively.
Figure 21. IRB Flag Timing and First Available Write when FIFO2 is Full (FWFT Mode)
29
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK
tCLKH
tCLKL
CLKA
CSA
LOW
W/RA
MBA
LOW
LOW
tENS2
tENH
ENA
EFA
A0-A35
HIGH
tA
Previous Word in FIFO2 Output Register
tSKEW1(1)
CLKB
Next Word From FIFO2
tCLKH
1
tCLK
tCLKL
2
tWFF
tWFF
FFB
FIFO2 Full
CSB
LOW
W/RB
LOW
tENS2
tENH
tENS2
tENH
MBB
ENB
tDS
B0-B35
tDH
Write
To FIFO2
3270 drw24
NOTES:
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.
2. If Port B size is word or byte, FFB is set LOW by the last word or byte write of the long word, respectively.
Figure 22. FFB Flag Timing and First Available Write when FIFO2 is Full (IDT Standard Mode)
30
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKA
tENS2
tENH
ENA
tSKEW2
(1)
1
CLKB
AEB
2
tPAE
tPAE
X1 Words in FIFO1
(X1+1) Words in FIFO1
tENS2
tENH
ENB
3270 drw25
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 = LOW, MBA = LOW), FIFO1 read (CSB = LOW, W/RB = HIGH, MBB = LOW). Data in the FIFO1 output register has been read from the FIFO.
3. If Port B size is word or byte, AEB is set LOW by the last word or byte read from FIFO1, respectively.
Figure 23. Timing for AEB when FIFO1 is Almost-Empty (IDT Standard and FWFT Modes)
CLKB
tENS2
tENH
ENB
tSKEW2
(1)
1
CLKA
2
tPAE
tPAE
AEA
X2 Words in FIFO2
(X2+1) Words in FIFO2
tENS2
tENH
ENA
3270 drw26
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 = LOW, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW). Data in the FIFO2 output register has been read from the FIFO.
3. If Port B size is word or byte, tSKEW2 is referenced to the rising CLKB edge that writes the last word or byte of the long word, respectively.
Figure 24. Timing for AEA when FIFO2 is Almost-Empty (IDT Standard and FWFT Modes)
tSKEW2
(1)
1
CLKA
tENS2
2
tENH
ENA
tPAF
tPAF
AFA
(D-Y1) Words in FIFO1
[D-(Y1+1)] Words in FIFO1
CLKB
tENS2
tENH
ENB
3270 drw 27
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 = HIGH, MBB = LOW). Data in the FIFO1 output register has been read from the FIFO.
3. D = Maximum FIFO Depth = 256 for the IDT723624, 512 for the IDT723634, 1,024 for the IDT723644.
4. If Port B size is word or byte, tSKEW2 is referenced to the rising CLKB edge that reads the last word or byte of the long word, respectively.
Figure 25. Timing for AFA when FIFO1 is Almost-Full (IDT Standard and FWFT Modes)
31
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
tSKEW2
CLKB
(1)
1
tENH
tENS2
COMMERCIAL TEMPERATURE RANGE
2
ENB
tPAF
tPAF
AFB
(D-Y2) Words in FIFO2
[D-(Y2+1)] Words in FIFO2
CLKA
tENH
tENS2
ENA
3270 drw28
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 = LOW, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW). Data in the FIFO2 output register has been read from the FIFO.
3. D = Maximum FIFO Depth = 256 for the IDT723624, 512 for the IDT723634, 1,024 for the IDT723644.
4. If Port B size is word or byte, AFB is set LOW by the last word or byte write of the long word, respectively.
Figure 26. Timing for AFB when FIFO2 is Almost-Full (IDT Standard and FWFT Modes)
CLKA
tENS1
tENH
tENS1
tENH
tENS2
tENH
tENS2
tENH
CSA
W/RA
MBA
ENA
tDS
W1
A0-A35
tDH
CLKB
tPMF
tPMF
MBF1
CSB
W/RB
MBB
tENS2
tENH
ENB
tEN
tPMR
tMDV
tDIS
W1 (Remains valid in Mail1 Register after read)
B0-B35
FIFO1 Output Register
3270 drw29
NOTE:
1. If Port B is configured for word size, data can be written to the Mail1 register using A0-A17 (A18-A35 are don't care inputs). In this first case B0-B17 will have valid data (B18-B35 will be
indeterminate). If Port B is configured for byte size, data can be written to the Mail1 Register using A0-A8 (A9-A35 are don't care inputs). In this second case, B0-B8 will have valid data
(B9-B35 will be indeterminate).
Figure 27. Timing for Mail1 Register and MBF1 Flag (IDT Standard and FWFT Modes)
32
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKB
tENS1
tENH
tENS1
tENH
tENS2
tENH
tENS2
tENH
CSB
W/RB
MBB
ENB
tDS
W1
B0-B35
tDH
CLKA
tPMF
tPMF
MBF2
CSA
W/RA
MBA
tENS2
tENH
ENA
tEN
tPMR
tDIS
tMDV
W1 (Remains valid in Mail 2 Register after read)
A0-A35
FIFO2 Output Register
3270 drw30
NOTE:
1. If Port B is configured for word size, data can be written to the Mail2 Register using B0-B17 (B18-B35 are don’t care inputs). In this first case A0-A17 will have valid data
(A18-A35 will be indeterminate). If Port B is configured for byte size, data can be written to the Mail2 Register using B0-B8 (B9-B35 are don’t care inputs). In this second
case, A0-A8 will have valid data (A9-A35 will be indeterminate).
Figure 28. Timing for Mail2 Register and MBF2 Flag (IDT Standard and FWFT Modes)
33
IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PARAMETER MEASUREMENT INFORMATION
5V
1.1 k Ω
From Output
Under Test
30 pF
680 Ω
(1)
PROPAGATION DELAY
LOAD CIRCUIT
3V
Timing
Input
1.5 V
High-Level
Input
GND
tS
1.5 V
th
3V
1.5 V
1.5 V
GND
tW
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
≈3 V
Input
1.5 V
Low-Level
Output
VOL
tPZH
1.5 V
tPHZ
3V
1.5 V
1.5 V
tPD
tPD
GND
VOH
VOH
High-Level
Output
3V
1.5 V
In-Phase
Output
≈ OV
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
1.5 V
1.5 V
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
3270 drw31
NOTE:
1. Includes probe and jig capacitance.
Figure 29. Output Load and AC Test Conditions
34
ORDERING INFORMATION
XXXXXX
Device Type
X
X
XX
XX
Power Speed Package
X
X
Process/
Temperature
Range
Blank
8
Tube or Tray
Tape and Reel
BLANK
Commercial (0°C to +70°C)
G
Green
PF
Thin Quad Flat Pack (TQFP, PK128-1)
15
Commercial Only
L
Low Power
723624
723634
723644
256 x 36 x 2 ⎯ SyncBiFIFOTM with Bus-Matching
512 x 36 x 2 ⎯ SyncFIFOTM with Bus-Matching
1,024 x 36 x 2 ⎯ SyncFIFOTM with Bus-Matching
Clock Cycle Time (tCLK)
Speed in Nanoseconds
3270 drw32
DATASHEET DOCUMENT HISTORY
10/04/2000
03/22/2001
08/01/2001
10/22/2008
06/18/2014
pgs. 1 through 35, except pgs. 20, 24-26, 32 and 33.
pgs. 6 and 7.
pgs. 1, 6, 8, 9 and 35.
pg. 35.
pgs. 1, 2, 3, 6, 8, 9 and 35.
CORPORATE HEADQUARTERS
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San Jose, CA 95138
for SALES:
800-345-7015 or 408-284-8200
fax: 408-284-2775
www.idt.com
35
for Tech Support:
408-360-1753
email: [email protected]