SN74ACT3622 [TI]
256 】 36 】 2 CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY; 256 】 36 】 2主频双向先入先出存储器
| 型号： | SN74ACT3622 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 256 】 36 】 2 CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY |
| 文件： | 总28页 (文件大小：418K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
Free-Running CLKA and CLKB Can Be
Asynchronous or Coincident
IRB, ORB, AEB, and AFB Flags
Synchronized by CLKB
Two Independent Clocked FIFOs Buffering
Data in Opposite Directions
Low-Power 0.8 µm Advanced CMOS
Technology
Mailbox-Bypass Register for Each FIFO
Supports Clock Frequencies up to 67 MHz
Fast Access Times of 11 ns
Programmable Almost-Full and
Almost-Empty Flags
Pin-to-Pin Compatible With the
SN74ACT3632 and SN74ACT3642
Microprocessor Interface Control Logic
IRA, ORA, AEA, and AFA Flags
Synchronized by CLKA
Package Options Include 120-Pin Thin
Quad Flat (PCB) and 132-Pin Plastic Quad
Flat (PQ) Packages
PCB PACKAGE
(TOP VIEW)
A35
A34
A33
A32
1
2
3
4
5
6
7
8
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
64
63
62
61
B35
B34
B33
B32
GND
B31
B30
B29
B28
B27
B26
V
A31
CC
A30
GND
A29
A28
A27
A26
A25
A24
A23
GND
A22
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
V
CC
B25
B24
GND
B23
B22
B21
B20
B19
B18
GND
B17
B16
V
CC
A21
A20
A19
A18
GND
A17
A16
A15
A14
A13
V
CC
B15
B14
B13
B12
GND
V
A12
CC
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright 1998, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
†
PQ PACKAGE
(TOP VIEW)
17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1 132 130 128
131
129
126 124 122 120 118
127 125 123
121 119
117
116
NC
B35
B34
B33
B32
GND
B31
B30
B29
B28
B27
B26
NC
NC
A35
A34
A33
A32
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
V
CC
A31
A30
GND
A29
A28
A27
A26
A25
A24
A23
GND
A22
V
CC
B25
B24
GND
B23
B22
B21
B20
B19
B18
GND
B17
B16
98
97
V
CC
A21
A20
A19
A18
GND
A17
A16
A15
A14
A13
96
95
94
93
92
V
91
CC
B15
B14
B13
B12
GND
NC
90
89
88
87
V
86
CC
A12
NC
85
NC
84
51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83
NC – No internal connection
†
Uses Yamaichi socket IC51-1324-828
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
description
The SN74ACT3622 is a high-speed, low-power CMOS clocked bidirectional FIFO memory. It supports clock
frequencies up to 67 MHz with read access times of 11 ns. Two independent 256 × 36 dual-port SRAM FIFOs
on the chip buffer data in opposite directions. Each FIFO has flags to indicate empty and full conditions and two
programmable flags almost full (AF) and almost empty (AE) 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. Two or more devices can be used
in parallel to create wider datapaths.
The SN74ACT3622 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 input-ready (IRA, IRB) flag and almost-full (AFA, AFB) flag of a FIFO are two-stage synchronized to the
port clock that writes data to its array. The output-ready (ORA, ORB) flag and almost-empty (AEA, AEB) flag
of a FIFO are two-stage synchronized to the port clock that reads data from its array. Offset values for the AF
and AE flags of the FIFO can be programmed from port A.
The SN74ACT3622 is characterized for operation from 0°C to 70°C.
For more information on this device family, see the application report FIFO Mailbox-Bypass Registers: Using
Bypass Registers to Initialize DMA Control (literature number SCAA007) and Metastability Performance of
Clocked FIFOs (literature number SCZA004).
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
functional block diagram
MBF1
Mail1
Register
CLKA
CSA
W/RA
ENA
Port-A
Control
Logic
MBA
256 × 36
SRAM
FIFO1,
Mail1
Reset
Logic
36
RST1
Write
Pointer
Read
Pointer
Status-Flag
IRA
AFA
ORB
AEB
Logic
FIFO1
FIFO2
36
Programmable-
Flag
Offset Registers
FS0
FS1
A0–A35
10
B0–B35
Status-Flag
Logic
ORA
AEA
IRB
AFB
36
Read
Write
Pointer
Pointer
FIFO2,
Mail2
Reset
Logic
RST2
CLKB
256 × 36
SRAM
Port-B
Control
Logic
CSB
W/RB
ENB
MBB
Mail2
Register
MBF2
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
Terminal Functions
TERMINAL
NAME
I/O
DESCRIPTION
A0–A35
I/O
O
Port-A data. The 36-bit bidirectional data port for side A.
Port-A almost-empty flag. Programmable flag synchronized to CLKA. AEA is low when the number of words in FIFO2
AEA
(port A) is less than or equal to the value in the almost-empty A offset register, X2.
Port-B almost-empty flag. Programmable flag synchronized to CLKB. AEB is low when the number of words in FIFO1
(port B) is less than or equal to the value in the almost-empty B offset register, X1.
Port-A almost-full flag. Programmable flag synchronized to CLKA. AFA is low when the number of empty locations in
(port A) FIFO1 is less than or equal to the value in the almost-full A offset register, Y1.
Port-B almost-full flag. Programmable flag synchronized to CLKB. AFB is low when the number of empty locations in
(port B) FIFO2 is less than or equal to the value in the almost-full B offset register, Y2.
O
AEB
AFA
O
O
AFB
B0–B35
CLKA
I/O
Port-B data. The 36-bit bidirectional data port for side B.
Port-A clock. CLKA is a continuous clock that synchronizes all data transfers through port A and can be asynchronous
or coincident to CLKB. IRA, ORA, AFA, and AEA are all synchronized to the low-to-high transition of CLKA.
I
Port-B clock. CLKB is a continuous clock that synchronizes all data transfers through port B and can be asynchronous
or coincident to CLKA. IRB, ORB, AFB, and AEB are synchronized to the low-to-high transition of CLKB.
CLKB
CSA
CSB
I
I
I
Port-A chip select. 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.
Port-B chip select. 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.
ENA
ENB
I
I
Port-A enable. ENA must be high to enable a low-to-high transition of CLKA to read or write data on port A.
Port-B enable. ENB must be high to enable a low-to-high transition of CLKB to read or write data on port B.
Flag offset selects. The low-to-high transition of a FIFO’s reset input latches the values of FS0 and FS1. If either FS0
or FS1 is high when a reset input goes high, one of three preset values is selected as the offset for the FIFO AF and
AE flags. If both FIFOs are reset simultaneously and both FS0 and FS1 are low when RST1 and RST2 go high, the
first four writes to FIFO1 program the almost-full and almost-empty offsets for both FIFOs.
FS1, FS0
I
Input-ready flag. IRA is synchronized to the low-to-high transition of CLKA. When IRA is low, FIFO1 is full and writes
to its array are disabled. IRA is set low when FIFO1 is reset and is set high on the second low-to-high transition of CLKA
after reset.
O
IRA
IRB
(port A)
Input-ready flag. IRB is synchronized to the low-to-high transition of CLKB. When IRB is low, FIFO2 is full and writes
to its array are disabled. IRB is set low when FIFO2 is reset and is set high on the second low-to-high transition of CLKB
after reset.
O
(port B)
Port-A mailbox select. 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.
MBA
MBB
MBF1
MBF2
I
Port-B mailbox select. 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.
I
Mail1 register flag. 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 when FIFO1 is reset.
O
O
Mail2 register flag. 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 also set high when FIFO2 is reset.
Output-ready flag. ORA is synchronized to the low-to-high transition of CLKA. When ORA is low, FIFO2 is empty and
reads from its memory are disabled. Ready data is present on the output register of FIFO2 when ORA is high. ORA
is forced low when FIFO2 is reset and goes high on the third low-to-high transition of CLKA after a word is loaded to
empty memory.
O
ORA
(port A)
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
Terminal Functions (continued)
TERMINAL
NAME
I/O
DESCRIPTION
Output-ready flag. ORB is synchronized to the low-to-high transition of CLKB. When ORB is low, FIFO1 is empty and
reads from its memory are disabled. Ready data is present on the output register of FIFO1 when ORB is high. ORB
is forced low when FIFO1 is reset and goes high on the third low-to-high transition of CLKB after a word is loaded to
empty memory.
O
ORB
(port B)
FIFO1 reset. To reset FIFO1, four low-to-high transitions of CLKA and four low-to-high transitions of CLKB must occur
while RST1 is low. The low-to-high transition of RST1 latches the status of FS0 and FS1 for AFA and AEB offset
selection. FIFO1 must be reset upon power up before data is written to its RAM.
I
I
RST1
RST2
FIFO2 reset. To reset FIFO2, four low-to-high transitions of CLKA and four low-to-high transitions of CLKB must occur
while RST2 is low. The low-to-high transition of RST2 latches the status of FS0 and FS1 for AFB and AEA offset
selection. FIFO2 must be reset upon power up before data is written to its RAM.
Port-A write/read select. A high on W/RA 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.
I
I
W/RA
W/RB
Port-B write/read select. A low on W/RB 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.
detailed description
reset
The FIFO memories of the SN74ACT3622 are reset separately by taking their reset (RST1, RST2) inputs low
for at least four port-A clock (CLKA) and four port-B clock (CLKB) low-to-high transitions. The reset inputs can
switch asynchronously to the clocks. A FIFO reset initializes the internal read and write pointers and forces the
input-ready (IRA, IRB) flag low, the output-ready (ORA, ORB) flag low, the almost-empty (AEA, AEB) flag low,
and the almost-full (AFA, AFB) flag high. Resetting a FIFO also forces the mailbox (MBF1, MBF2) flag of the
parallel mailbox register high. After a FIFO is reset, its IR flag is set high after two clock cycles to begin normal
operation. A FIFO must be reset after power up before data is written to its memory.
A low-to-high transition on a FIFO reset (RST1, RST2) input latches the value of the flag-select (FS0, FS1)
inputs for choosing the almost-full and almost-empty offset programming method (see almost-empty flag and
almost-full flag offset programming).
almost-empty flag and almost-full flag offset programming
Four registers in the SN74ACT3622 are used to hold the offset values for the AE and AF flags. The port-B
almost-empty (AEB) flag offset register is labeled X1 and the port-A almost-empty (AEA) flag offset register is
labeled X2. The port-A almost-full (AFA) flag offset register is labeled Y1 and the port-B almost-full (AFB) flag
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 or they can be programmed from port A
(see Table 1).
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
almost-empty flag and almost-full flag offset programming (continued)
Table 1. Flag Programming
†
‡
FS1
H
FS0
H
RST1 RST2
X1 AND Y1 REGISTERS
X2 AND Y2 REGISTERS
↑
X
↑
X
↑
64
X
X
64
X
H
H
H
L
X
↑
16
X
H
L
X
↑
16
X
L
H
X
↑
8
L
H
X
↑
X
8
L
L
↑
Programmed from port A
Programmed from port A
†
‡
X1 register holds the offset for AEB; Y1 register holds the offset for AFA.
X2 register holds the offset for AEA; Y2 register holds the offset for AFB.
To load the FIFO AE flag and AF flag offset registers with one of the three preset values listed in Table 1, at least
one of the flag-select inputs must be high during the low-to-high transition of its reset input. For example, to load
the preset value of 64 into X1 and Y1, FS0 and FS1 must be high when FIFO1 reset (RST1) returns high.
Flag-offset registers associated with FIFO2 are loaded with one of the preset values in the same way with FIFO2
reset (RST2). When using one of the preset values for the flag offsets, the FIFOs can be reset simultaneously
or at different times.
To program the X1, X2, Y1, and Y2 registers from port A, both FIFOs should be reset simultaneously with FS0
and FS1 low during the low-to-high transition of the reset inputs. After this reset is complete, the first four writes
to FIFO1 do not store data in RAM but load the offset registers in the order Y1, X1, Y2, X2. Each offset register
uses port-A inputs (A7–A0). 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. After all the offset registers are
programmed from port A, the port-B input-ready (IRB) flag is set high and both FIFOs begin normal operation.
FIFO write/read operation
The state of the 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 A0–A35 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
ishigh, ENAishigh, MBAislow, andIRAishigh. DataisreadfromFIFO2totheA0–A35outputsbyalow-to-high
transition of CLKA when CSA is low, W/RA is low, ENA is high, MBA is low, and ORA is high (see Table 2). FIFO
reads and writes on port A are independent of any concurrent port-B operation.
Table 2. Port-A Enable Function Table
CSA W/RA ENA
MBA CLKA
A0–A35 OUTPUTS
In high-impedance state
In high-impedance state
In high-impedance state
In high-impedance state
Active, FIFO2 output register
Active, FIFO2 output register
Active, mail2 register
PORT FUNCTION
None
H
L
L
L
L
L
L
L
X
H
H
H
L
X
L
X
X
L
X
X
↑
None
H
H
L
FIFO1 write
Mail1 write
None
H
L
↑
X
↑
L
H
L
L
FIFO2 read
None
L
H
H
X
↑
L
H
Active, mail2 register
Mail2 read (set MBF2 high)
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
FIFO write/read operation (continued)
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) 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 is high or W/RB is low. The B0–B35 outputs are active 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 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 ORB is high (see Table 3). FIFO
reads and writes on port B are independent of any concurrent port-A operation.
Table 3. Port-B Enable Function Table
CSB W/RB ENB
MBB CLKB
B0–B35 OUTPUTS
In high-impedance state
In high-impedance state
In high-impedance state
In high-impedance state
Active, FIFO1 output register
Active, FIFO1 output register
Active, mail1 register
PORT FUNCTION
None
H
L
L
L
L
L
L
L
X
L
X
L
X
X
L
X
X
↑
None
L
H
H
L
FIFO2 write
Mail2 write
None
L
H
L
↑
H
H
H
H
X
↑
H
L
L
FIFO1 read
None
H
H
X
↑
H
Active, mail1 register
Mail1 read (set MBF1 high)
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 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.
When a FIFO OR flag is low, the next data word is sent to the FIFO output register automatically by the
low-to-high transition of the port clock that sets the OR flag high. When the OR flag is high, an available data
word is clocked to the FIFO output register only when a FIFO read is selected by the port’s chip select, write/read
select, enable, and mailbox select.
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. ORA, AEA, IRA, and AFA are synchronized to CLKA. ORB, AEB, IRB, and AFB
are synchronized to CLKB. Tables 4 and 5 show the relationship of each port flag to FIFO1 and FIFO2.
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
synchronized FIFO flags (continued)
Table 4. FIFO1 Flag Operation
SYNCHRONIZED
TO CLKB
SYNCHRONIZED
TO CLKA
NUMBER OF WORDS IN
†‡
FIFO1
ORB
L
AEB
L
AFA
H
IRA
H
0
1 to X1
(X1 + 1) to [256 – (Y1 + 1)]
(256 – Y1) to 255
256
H
L
H
H
H
H
H
H
H
H
L
H
H
H
L
L
†
‡
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 reset
of FIFO1 or programmed from port A.
When a word loaded to an empty FIFO is shifted to the output register, its
previous FIFO memory location is free.
Table 5. FIFO2 Flag Operation
SYNCHRONIZED
TO CLKA
SYNCHRONIZED
TO CLKB
NUMBER OF WORDS IN
†‡
FIFO2
ORA
L
AEA
L
AFB
H
IRB
H
0
1 to X2
(X2 + 1) to [256 – (Y2 + 1)]
(256 – Y2) to 255
256
H
L
H
H
H
H
H
H
H
H
L
H
H
H
L
L
†
‡
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 reset
of FIFO2 or programmed from port A.
When a word loaded to an empty FIFO is shifted to the output register, its
previous FIFO memory location is free.
output-ready flags (ORA, ORB)
The OR flag of a FIFO is synchronized to the port clock that reads data from its array. When the OR flag is high,
new data is present in the FIFO output register. When the OR flag is low, the previous data word is present in
the FIFO output register and attempted FIFO reads are ignored.
A FIFO read pointer is incremented each time a new word is clocked to its output register. 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 OR flag
synchronizingclock;therefore, anORflagislowifawordinmemoryisthenextdatatobesenttotheFIFOoutput
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 OR flag of the FIFO remains low until the third low-to-high transition of the synchronizing
clock occurs, simultaneously forcing the OR flag high and shifting the word to the FIFO output register.
A low-to-high transition on an OR flag synchronizing clock begins the first synchronization cycle of a write if the
clock transition occurs at time t , or greater, after the write. Otherwise, the subsequent clock cycle can be the
sk1
first synchronization cycle (see Figures 7 and 8).
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input-ready flags (IRA, IRB)
The IR flag of a FIFO is synchronized to the port clock that writes data to its array. When the IR flag is high, a
memory location is free in the SRAM to receive new data. No memory locations are free when the IR flag is low
and attempted writes to the FIFO are ignored.
Each time a word is written to a FIFO, its write pointer is incremented. From the time a word is read from a FIFO,
its previous memory location is ready to be written in a minimum of two cycles of the IR flag synchronizing clock;
therefore, an IR flag is low if less than two cycles of the IR flag synchronizing clock have elapsed since the next
memory write location has been read. The second low-to-high transition on the IR flag synchronizing clock after
the read sets the IR flag high.
A low-to-high transition on an IR flag synchronizing clock begins the first synchronization cycle of a read if the
clock transition occurs at time t , or greater, after the read. Otherwise, the subsequent clock cycle can be the
sk1
first synchronization cycle (see Figures 9 and 10).
almost-empty flags (AEA, AEB)
The AE flag of a FIFO is synchronized to the port clock that reads data from its array. The AE state is defined
by the contents of register X1 for AEB and register X2 for AEA. These registers are loaded with preset values
duringaFIFOresetorprogrammedfromportA(seealmost-emptyflagandalmost-fullflagoffsetprogramming).
An AE flag is low when its FIFO contains X or fewer 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 AE flag synchronizing clock are required after a FIFO write for its AE flag to
reflect the new level of fill; therefore, the AE 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
AE 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 AE flag synchronizing clock begins the first
synchronization cycle if it occurs at time t , or greater, after the write that fills the FIFO to (X + 1) words.
sk2
Otherwise, the subsequent synchronizing clock cycle can be the first synchronization cycle (see Figures 11 and
12).
almost-full flags (AFA, AFB)
The AF flag of a FIFO is synchronized to the port clock that writes data to its array. The AF state is defined by
the contents of register Y1 for AFAand register Y2 for AFB. These registers are loaded with preset values during
a FIFO reset or programmed from port A (see almost-empty flag and almost-full flag offset programming). An
AF flag is low when the number of words in its FIFO is greater than or equal to (256 – Y). An AF flag is high when
the number of words in its FIFO is less than or equal to [256 – (Y + 1)]. A data word present in the FIFO output
register has been read from memory.
Two low-to-high transitions of the AF flag synchronizing clock are required after a FIFO read for its AF flag to
reflect the new level of fill; therefore, the AF flag of a FIFO containing [256 – (Y + 1)] or fewer words remains
low if two cycles of its synchronizing clock have not elapsed since the read that reduced the number of words
inmemoryto[256 – (Y + 1)]. An AFflagissethighbythesecondlow-to-hightransitionofitssynchronizingclock
after the FIFO read that reduces the number of words in memory to [256 – (Y + 1)]. A low-to-high transition of
an AF flag synchronizing clock begins the first synchronization cycle if it occurs at time t , or greater, after the
sk2
read that reduces the number of words in memory to [256 – (Y + 1)]. Otherwise, the subsequent synchronizing
clock cycle can be the first synchronization cycle (see Figures 13 and 14).
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
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 with 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 with MBB
high. 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 and with MBB high. 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 and with MBA high. The data in a mail register
remains intact after it is read and changes only when new data is written to the register.
CLKA
t
h(RS)
CLKB
t
h(FS)
t
su(RS)
t
su(FS)
RST1
FS1, FS0
0,1
t
t
pd(C-IR)
pd(C-IR)
IRA
ORB
AEB
t
pd(C-OR)
t
t
t
pd(R-F)
pd(R-F)
pd(R-F)
AFA
MBF1
†
Figure 1. FIFO1 Reset Loading X1 and Y1 With a Preset Value of Eight
†
FIFO2 is reset in the same manner to load X2 and Y2 with a preset value.
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
CLKA
4
t
su(FS)
RST1,
RST2
t
h(FS)
FS1, FS0
0,0
t
pd(C-IR)
IRA
ENA
t
su(EN)
†
t
sk1
t
h(EN)
t
t
h(D)
su(D)
A0–A35
AFA Offset
(Y1)
AEB Offset
(X1)
AFB Offset
(Y2)
AEA Offset
(X2)
First Word to FIFO1
CLKB
IRB
1
2
t
pd(C-IR)
†
t
is the minimum time between the rising CLKA edge and a rising CLKB edge for IRB to transition high in the next cycle. If the time
sk1
between the rising edge of CLKA and rising edge of CLKB is less than t
, IRB may transition high one cycle later than shown.
sk1
NOTE A: CSA = L, W/RA = H, MBA = L. It is not necessary to program offset register on consecutive clock cycles.
Figure 2. Programming the AF Flag and AE Flag Offset Values After Reset
t
c
t
t
w(CLKL)
w(CLKH)
CLKA
IRA
t
t
su(EN)
h(EN)
CSA
t
t
t
t
t
su(EN)
su(EN)
su(EN)
h(EN)
W/RA
MBA
ENA
h(EN)
t
t
h(EN)
h(EN)
t
t
t
t
h(EN)
su(EN)
su(EN)
t
su(D)
h(D)
‡
W1
‡
W2
A0–A35
No Operation
‡
Written to FIFO1
Figure 3. Port-A Write-Cycle Timing for FIFO1
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
t
c
t
t
w(CLKL)
w(CLKH)
CLKB
IRB
t
t
t
su(EN)
h(EN)
CSB
t
t
su(EN)
h(EN)
W/RB
MBB
ENB
t
t
su(EN)
h(EN)
t
t
h(EN)
h(EN)
t
t
t
t
su(EN)
h(EN)
su(EN)
su(EN)
t
su(D)
h(D)
†
W1
†
W2
B0–B35
No Operation
†
Written to FIFO2
Figure 4. Port-B Write-Cycle Timing for FIFO2
t
c
t
t
w(CLKL)
w(CLKH)
CLKB
ORB
CSB
W/RB
MBB
t
su(EN)
t
t
t
t
t
h(EN) su(EN)
h(EN)
su(EN)
h(EN)
ENB
t
No
Operation
pd(M-DV)
t
dis
t
a
t
a
t
en
‡
W1
‡
W2
‡
W3
B0–B35
‡
Read from FIFO1
Figure 5. Port-B Read-Cycle Timing for FIFO1
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
t
c
t
t
w(CLKL)
w(CLKH)
CLKA
ORA
CSA
W/RA
MBA
t
su(EN)
t
t
t
t
t
h(EN)
h(EN) su(EN)
h(EN)
su(EN)
ENA
t
No
Operation
pd(M-DV)
t
dis
t
a
t
a
t
en
†
W1
†
W2
†
W3
A0–A35
†
Read from FIFO2
Figure 6. Port-A Read-Cycle Timing for FIFO2
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
t
c
t
t
w(CLKL)
w(CLKH)
CLKA
Low
CSA
W/RA
High
t
su(EN)
t
h(EN)
MBA
ENA
t
su(EN)
t
h(EN)
High
IRA
t
su(D)
t
h(D)
A0–A35
W1
t
t
c
†
t
sk1
w(CLKL)
t
w(CLKH)
1
2
t
3
CLKB
ORB
t
pd(C-OR)
pd(C-OR)
Old Data in FIFO1 Output Register
CSB Low
W/RB
High
MBB Low
ENB
t
h(EN)
t
su(EN)
t
a
B0–B35
W1
Old Data in FIFO1 Output Register
†
t
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
sk1
FIFO1 output register in three CLKB cycles. If the time between the rising CLKA edge and rising CLKB edge is less than t
of ORB high and load of the first word to the output register may occur one CLKB cycle later than shown.
, the transition
sk1
Figure 7. ORB-Flag Timing and First Data-Word Fall Through When FIFO1 Is Empty
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
t
c
t
t
w(CLKL)
w(CLKH)
CLKB
Low
Low
CSB
W/RB
t
t
su(EN)
t
t
h(EN)
MBB
ENB
su(EN)
h(EN)
High
IRB
t
su(D)
t
h(D)
B0–B35
W1
t
t
†
c
t
sk1
w(CLKL)
t
w(CLKH)
1
2
t
3
CLKA
ORA
t
pd(C-OR)
pd(C-OR)
Old Data in FIFO2 Output Register
CSA Low
W/RA
Low
MBA Low
ENA
t
h(EN)
t
su(EN)
t
a
A0–A35
W1
Old Data in FIFO2 Output Register
†
t
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
sk1
FIFO2 output register in three CLKA cycles. If the time between the rising CLKB edge and rising CLKA edge is less than t
of ORA high and load of the first word to the output register may occur one CLKA cycle later than shown.
, the transition
sk1
Figure 8. ORA-Flag Timing and First Data-Word Fall Through When FIFO2 Is Empty
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
t
c
t
t
w(CLKL)
w(CLKH)
CLKB
Low
CSB
W/RB
MBB
High
Low
t
t
h(EN)
su(EN)
ENB
ORB
High
t
a
B0–B35 Previous Word in FIFO1 Output Register
Next Word From FIFO1
†
t
sk1
t
c
t
t
w(CLKH)
w(CLKL)
1
2
CLKA
IRA
t
t
pd(C-IR)
pd(C-IR)
FIFO1 Full
CSA
W/RA
MBA
Low
High
t
t
t
h(EN)
su(EN)
t
su(EN)
h(EN)
ENA
t
t
su(D)
h(D)
A0–A35
To FIFO1
†
t
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
sk1
between the rising CLKB edge and rising CLKA edge is less than t
, IRA may transition high one CLKA cycle later than shown.
sk1
Figure 9. IRA-Flag Timing and First Available Write When FIFO1 Is Full
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
t
c
t
t
w(CLKL)
w(CLKH)
CLKA
Low
Low
Low
CSA
W/RA
MBA
t
t
h(EN)
su(EN)
ENA
ORA
High
t
a
A0–A35 Previous Word in FIFO2 Output Register
Next Word From FIFO2
†
t
sk1
t
c
t
t
w(CLKL)
w(CLKH)
1
2
CLKB
IRB
t
t
pd(C-IR)
pd(C-IR)
FIFO2 Full
CSB
W/RB
MBB
Low
Low
t
t
t
h(EN)
su(EN)
t
su(EN)
h(EN)
h(D)
ENB
t
t
su(D)
B0–B35
To FIFO2
†
t
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
sk1
between the rising CLKA edge and rising CLKB edge is less than t
, IRB may transition high one CLKB cycle later than shown.
sk1
Figure 10. IRB-Flag Timing and First Available Write When FIFO2 Is Full
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
CLKA
ENA
t
h(EN)
t
su(EN)
†
t
sk2
CLKB
AEB
1
2
t
t
pd(C-AE)
pd(C-AE)
X1 Words in FIFO1
(X1 + 1) Words in FIFO1
t
h(EN)
t
su(EN)
ENB
†
t
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
sk2
time between the rising CLKA edge and rising CLKB edge is less than t
, AEB may transition high one CLKB cycle later than shown.
sk2
NOTE A: FIFO1 write (CSA = L, W/RA = H, MBA = L), FIFO1 read (CSB = L, W/RB = H, MBB = L). Data in the FIFO1 output register
has been read from the FIFO.
Figure 11. Timing for AEB When FIFO1 Is Almost Empty
CLKB
t
h(EN)
t
su(EN)
ENB
‡
t
sk2
CLKA
AEA
1
2
t
t
pd(C-AE)
pd(C-AE)
X2 Words in FIFO2
(X2 + 1) Words in FIFO2
t
h(EN)
t
su(EN)
ENA
‡
t
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
sk2
time between the rising CLKB edge and rising CLKA edge is less than t
, AEA may transition high one CLKA cycle later than shown.
sk2
NOTE A: FIFO2 write (CSB = L, W/RB = L, MBB = L), FIFO2 read (CSA = L, W/RA = L, MBA = L). Data in the FIFO2 output register
has been read from the FIFO.
Figure 12. Timing for AEA When FIFO2 Is Almost Empty
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
†
t
sk2
CLKA
ENA
1
2
t
h(EN)
t
su(EN)
t
t
pd(C-AF)
pd(C-AF)
(256 – Y1) Words in FIFO1
AFA
[256 – (Y1 + 1)] Words in FIFO1
CLKB
ENB
t
h(EN)
t
su(EN)
†
t
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
sk2
time between the rising CLKA edge and rising CLKB edge is less than t
, AFA may transition high one CLKB cycle later than shown.
sk2
NOTE A: FIFO1 write (CSA = L, W/RA = H, MBA = L), FIFO1 read (CSB = L, W/RB = H, MBB = L). Data in the FIFO1 output register
has been read from the FIFO.
Figure 13. Timing for AFA When FIFO1 Is Almost Full
‡
t
sk2
CLKB
ENB
1
2
t
h(EN)
t
su(EN)
t
t
pd(C-AF)
pd(C-AF)
(256 – Y2) Words in FIFO2
AFB
[256 – (Y2 + 1)] Words in FIFO2
CLKA
ENA
t
h(EN)
t
su(EN)
‡
t
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
sk2
time between the rising CLKB edge and rising CLKA edge is less than t
, AFB may transition high one CLKA cycle later than shown.
sk2
NOTE A: FIFO2 write (CSB = L, W/RB= L, MBB = L), FIFO2 read (CSA = L, W/RA = L, MBA = L). Data in the FIFO2 output register has
been read from the FIFO.
Figure 14. Timing for AFB When FIFO2 Is Almost Full
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
CLKA
t
h(EN)
t
su(EN)
CSA
W/RA
MBA
ENA
t
h(D)
t
su(D)
A0–A35
W1
CLKB
MBF1
t
t
pd(C-MF)
pd(C-MF)
CSB
W/RB
MBB
ENB
t
h(EN)
t
su(EN)
t
pd(M-DV)
t
dis
t
en
t
pd(C-MR)
B0–B35
W1 (remains valid in mail1 register after read)
FIFO1 Output Register
Figure 15. Timing for Mail1 Register and MBF1 Flag
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
CLKB
t
h(EN)
t
su(EN)
CSB
W/RB
MBB
ENB
t
h(D)
t
su(D)
B0–B35
W1
CLKA
MBF2
t
t
pd(C-MF)
pd(C-MF)
CSA
W/RA
MBA
ENA
t
h(EN)
t
su(EN)
t
pd(M-DV)
t
dis
t
en
t
pd(C-MR)
A0–A35
W1 (remains valid in mail2 register after read)
FIFO2 Output Register
Figure 16. Timing for Mail2 Register and MBF2 Flag
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
†
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage range, V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
CC
Input voltage range, V (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to V
+ 0.5 V
+ 0.5 V
I
CC
CC
Output voltage range, V (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to V
O
Input clamp current, I (V < 0 or V > V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
IK
I
I
CC
Output clamp current, I
(V < 0 or V > V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
OK
O O CC
Continuous output current, I (V = 0 to V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
Continuous current through V
Package thermal impedance, θ (see Note 2): PCB package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28°C/W
O
O
CC
CC
or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±400 mA
JA
PQ package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46°C/W
Storage temperature range, T
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
stg
†
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.
NOTES: 1. The input and output voltage ratings may be exceeded provided the input and output current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51.
recommended operating conditions
MIN
4.5
2
MAX
UNIT
V
V
V
V
Supply voltage
5.5
CC
High-level input voltage
Low-level input voltage
High-level output current
Low-level output current
Operating free-air temperature
V
IH
0.8
–4
8
V
IL
I
I
mA
mA
°C
OH
OL
T
A
0
70
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CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
†
PARAMETER
TEST CONDITIONS
= –4 mA
MIN TYP
MAX
UNIT
V
V
V
V
V
V
V
V
= 4.5 V,
= 4.5 V,
= 5.5 V,
= 5.5 V,
= 5.5 V,
I
I
2.4
OH
CC
CC
CC
CC
CC
OH
= 8 mA
0.5
±5
V
OL
OL
I
I
I
V = V
or 0
µA
µA
µA
I
I
CC
V
= V
or 0
±5
OZ
CC
O
CC
V = V
– 0.2 V or 0
CSA = V
400
I
CC
A0–A35
B0–B35
A0–A35
B0–B35
0
0
IH
IH
IL
IL
CSB = V
CSA = V
CSB = V
V
CC
= 5.5 V, One input at 3.4 V,
‡
1
1
1
mA
∆I
CC
Other inputs at V
or GND
CC
All other inputs
C
C
V = 0,
f = 1 MHz
f = 1 MHz
4
8
pF
pF
i
I
V
O
= 0,
o
†
‡
All typical values are at V
= 5 V, T = 25°C.
A
CC
This is the supply current when each input is at one of the specified TTL voltage levels rather than 0 V or V
.
CC
timing requirements over recommended ranges of supply voltage and operating free-air
temperature (see Figures 1 through 17)
’ACT3622-15 ’ACT3622-20 ’ACT3622-30
UNIT
MIN
MAX
MIN
MAX
MIN
MAX
f
t
t
t
t
Clock frequency, CLKA or CLKB
66.7
50
33.4
MHz
ns
clock
Clock cycle time, CLKA or CLKB
15
6
20
8
30
10
10
6
c
Pulse duration, CLKA and CLKB high
Pulse duration, CLKA and CLKB low
ns
w(CLKH)
w(CLKL)
su(D)
6
8
ns
Setup time, A0–A35 before CLKA↑ and B0–B35 before CLKB↑
4
5
ns
Setup time, CSA, W/RA, ENA, and MBA before CLKA↑; CSB,
W/RB, ENB, and MBB before CLKB↑
t
4.5
5
6
ns
su(EN)
§
t
t
t
Setup time, RST1 or RST2 low before CLKA↑ or CLKB↑
5
7.5
0
6
8.5
0
7
9.5
0
ns
ns
ns
su(RS)
su(FS)
h(D)
Setup time, FS0 and FS1 before RST1 and RST2 high
Hold time, A0–A35 after CLKA↑ and B0–B35 after CLKB↑
Hold time, CSA, W/RA, ENA, and MBA after CLKA↑; CSB, W/RB,
ENB, and MBB after CLKB↑
t
0
0
0
ns
h(EN)
§
t
t
Hold time, RST1 or RST2 low after CLKA↑ or CLKB↑
4
1
4
2
5
2
ns
ns
h(RS)
Hold time, FS0 and FS1 after RST1 and RST2 high
h(FS)
Skew time between CLKA↑ and CLKB↑ for ORA, ORB, IRA, and
IRB
¶
t
7.5
12
9
11
20
ns
ns
sk1
Skew time between CLKA↑ and CLKB↑ for AEA, AEB, AFA, and
AFB
¶
t
16
sk2
§
¶
Requirement to count the clock edge as one of at least four needed to reset a FIFO
Skew time is not a timing constraint for proper device operation and is included only to illustrate the timing relationship between CLKA cycle and
CLKB cycle.
24
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
switching characteristics over recommended ranges of supply voltage and operating free-air
temperature, C = 30 pF (see Figures 1 through 17)
L
’ACT3622-15 ’ACT3622-20 ’ACT3622-30
PARAMETER
UNIT
MIN
MAX
MIN
50
3
MAX
MIN
MAX
f
t
t
t
t
t
CLKA or CLKB
66.7
33.4
MHz
ns
max
Access time, CLKA↑ to A0–A35 and CLKB↑ to B0–B35
Propagation delay time, CLKA↑ to IRA and CLKB↑ to IRB
Propagation delay time, CLKA↑ to ORA and CLKB↑ to ORB
Propagation delay time, CLKA↑ to AEA and CLKB↑ to AEB
Propagation delay time, CLKA↑ to AFA and CLKB↑ to AFB
3
2
1
1
1
11
8
13
10
10
10
10
3
2
1
1
1
15
12
12
12
12
a
2
ns
pd(C-IR)
pd(C-OR)
pd(C-AE)
pd(C-AF)
8
1
ns
8
1
ns
8
1
ns
Propagation delay time, CLKA↑ to MBF1 low or MBF2 high and
CLKB↑ to MBF2 low or MBF1 high
t
t
t
t
t
t
0
3
3
1
2
1
8
13.5
11
0
3
3
1
2
1
10
15
13
20
13
12
0
3
3
1
2
1
12
17
15
30
14
14
ns
ns
ns
ns
ns
ns
pd(C-MF)
pd(C-MR)
pd(M-DV)
pd(R-F)
en
†
Propagation delay time, CLKA↑ to B0–B35 and CLKB↑ to
‡
A0–A35
Propagation delay time, MBA to A0–A35 valid and MBB to
B0–B35 valid
Propagation delay time, RST1 low to AEB low, AFA high, and
MBF1 high, and RST2 low to AEA low, AFB high, and MBF2 high
15
Enable time, CSA and W/RA low to A0–A35 active and CSB low
and W/RB high to B0–B35 active
12
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
11
dis
†
‡
Writing data to the mail1 register when the B0–B35 outputs are active and MBB is high
Writing data to the mail2 register when the A0–A35 outputs are active and MBA is high
25
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
PARAMETER MEASUREMENT INFORMATION
5 V
1.1 kΩ
From Output
Under Test
30 pF
(see Note A)
680 Ω
LOAD CIRCUIT
3 V
3 V
Timing
Input
High-Level
Input
1.5 V
1.5 V
1.5 V
1.5 V
GND
GND
3 V
t
h
t
t
su
w
Data,
Enable
Input
3 V
1.5 V
1.5 V
Low-Level
Input
1.5 V
GND
GND
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
VOLTAGE WAVEFORMS
PULSE DURATIONS
3 V
Output
Enable
1.5 V
1.5 V
GND
t
PLZ
t
PZL
≈ 3 V
3 V
Low-Level
Output
1.5 V
1.5 V
1.5 V
Input
V
V
OL
GND
t
PZH
t
t
pd
pd
OH
High-Level
Output
V
V
OH
1.5 V
In-Phase
Output
1.5 V
1.5 V
≈ 0 V
OL
t
PHZ
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
NOTES: A. Includes probe and jig capacitance
B.
C.
t
t
and t
and t
are the same as t
.
en
PZL
PLZ
PZH
PHZ
are the same as t
.
dis
Figure 17. Load Circuit and Voltage Waveforms
26
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74ACT3622
256 × 36 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS247D – AUGUST 1993 – REVISED APRIL 1998
TYPICAL CHARACTERISTICS
SUPPLY CURRENT
vs
CLOCK FREQUENCY
300
250
200
150
100
50
f
= 1/2 f
clock
data
= 75°C
T
A
C
= 0 pF
L
V
CC
= 5.5 V
V
CC
= 5 V
V
CC
= 4.5 V
0
0
10
20
30
40
50
60
70
f
– Clock Frequency – MHz
clock
Figure 18
27
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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