TI SN74ABT7819A-20PN

SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
D
D
D
D
D
D
Member of the Texas Instruments
Widebus Family
Free-Running CLKA and CLKB Can Be
Asynchronous or Coincident
Read and Write Operations Synchronized
to Independent System Clocks
Two Separate 512 × 18 Clocked FIFOs
Buffering Data in Opposite Directions
IRA and ORA Synchronized to CLKA
IRB and ORB Synchronized to CLKB
D
D
D
D
D
D
Microprocessor Interface Control Logic
Programmable Almost-Full/Almost-Empty
Flag
Fast Access Times of 9 ns With a 50-pF
Load and Simultaneous Switching Data
Outputs
Data Rates up to 100 MHz
Advanced BiCMOS Technology
Package Options Include 80-Pin Plastic
Quad Flatpack (PH) and 80-Pin Thin Plastic
Quad Flatpack (PN)
CSA
W/RA
GND
WENA
CLKA
RENA
ORA
VCC
VCC
ORB
RENB
CLKB
WENB
GND
W/RB
CSB
PH PACKAGE
(TOP VIEW)
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65
RSTA
PENA
AF/AEA
HFA
IRA
GND
A0
A1
VCC
A2
A3
GND
A4
A5
GND
A6
A7
GND
A8
A9
VCC
A10
A11
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
RSTB
PENB
AF/AEB
HFB
IRB
GND
B0
B1
VCC
B2
B3
GND
B4
B5
GND
B6
B7
GND
B8
B9
VCC
B10
B11
GND
A12
A13
V CC
A14
A15
GND
A16
A17
B17
B16
GND
B15
B14
VCC
B13
B12
25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
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.
Widebus is a trademark of Texas Instruments.
Copyright  2002, 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.
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1
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
RENB
CLKB
WENB
GND
W/RB
CSB
RSTB
PENB
PENA
RSTA
CSA
W/RA
GND
WENA
CLKA
RENA
ORA
VCC
VCC
ORB
PN PACKAGE
(TOP VIEW)
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61
AF/AEA
HFA
IRA
GND
A0
A1
VCC
A2
A3
GND
A4
A5
GND
A6
A7
GND
A8
A9
VCC
A10
1
60
2
59
3
58
4
57
5
56
6
55
7
54
8
53
9
52
10
51
11
50
12
49
13
48
14
47
15
46
16
45
17
44
18
43
19
42
20
41
AF/AEB
HFB
IRB
GND
B0
B1
VCC
B2
B3
GND
B4
B5
GND
B6
B7
GND
B8
B9
VCC
B10
A11
GND
A12
A13
V CC
A14
A15
GND
A16
A17
B17
B16
GND
B15
B14
V CC
B13
B12
GND
B11
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
description
A FIFO memory is a storage device that allows data to be written into and read from its array at independent
data rates. The SN74ABT7819A is a high-speed, low-power, BiCMOS, bidirectional, clocked FIFO memory.
Two independent 512 × 18 dual-port SRAM FIFOs (FIFOA, FIFOB) on the chip buffer data in opposite directions.
Each FIFO has flags to indicate empty and full conditions, a half-full flag, and a programmable
almost-full/almost-empty flag.
The SN74ABT7819A 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 continuous (free-running) port clock by enable
signals. The continuous 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 state of the A0–A17 outputs is controlled by the port-A chip select (CSA) and the port-A write/read select
(W/RA). When both CSA and W/RA are low, the outputs are active. The A0–A17 outputs are in the
high-impedance state when either CSA or W/RA is high. Data is written to FIFOA–B from port A on the
low-to-high transition of the port-A clock (CLKA) input when CSA is low, W/RA is high, the port-A write enable
(WENA) is high, and the port-A input-ready (IRA) flag is high. Data is read from FIFOB–A to the A0–A17 outputs
on the low-to-high transition of CLKA when CSA is low, W/RA is low, the port-A read enable (RENA) is high,
and the port-A output-ready (ORA) flag is high.
2
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SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
description (continued)
The state of the B0–B17 outputs is controlled by the port-B chip select (CSB) and the port-B write/read select
(W/RB). When both CSB and W/RB are low, the outputs are active. The B0–B17 outputs are in the
high-impedance state when either CSB or W/RB is high. Data is written to FIFOB–A from port B on the
low-to-high transition of the port-B clock (CLKB) when CSB is low, W/RB is high, the port-B write enable (WENB)
is high, and the port-B input-ready (IRB) flag is high. Data is read from FIFOA–B to the B0–B17 outputs on the
low-to-high transition of CLKB when CSB is low, W/RB is low, the port-B read enable (RENB) is high, and the
port-B output-ready (ORB) flag is high.
The setup- and hold-time constraints for the chip selects (CSA, CSB) and write/read selects (W/RA, W/RB)
enable write and read operations on memory and are not related to the high-impedance control of the data
outputs. If a port read enable (RENA or RENB) and write enable (WENA or WENB) are set low during a clock
cycle, the chip select and write/read select can switch at any time during the cycle to change the state of the
data outputs.
The input-ready (IR) and output-ready (OR) flags of a FIFO are two-stage synchronized to the port clocks for
use as reliable control signals. CLKA synchronizes the status of the input-ready flag of FIFOA–B (IRA) and the
output-ready flag of FIFOB–A (ORA). CLKB synchronizes the status of the input-ready flag of FIFOB–A (IRB)
and the output-ready flag of FIFOA–B (ORB). When the IR flag of a port is low, the FIFO receiving input from
the port is full and writes are disabled to its array. When the OR flag of a port is low, the FIFO that outputs data
to the port is empty and reads from its memory are disabled. The first word loaded to an empty memory is sent
to the FIFO output register at the same time its OR flag is asserted (high). When the memory is read empty and
the OR flag is forced low, the last valid data remains on the FIFO outputs until the OR flag is asserted (high)
again. In this way, a high on the OR flag indicates new data is present on the FIFO outputs.
The SN74ABT7819A is characterized for operation from 0°C to 70°C.
Function Tables
PORT A
SELECT INPUTS
W/RA
WENA
RENA
A0 A17
A0–A17
PORT A OPERATION
PORT-A
CLKA
CSA
X
H
X
X
X
High Z
None
↑
L
H
H
X
High Z
Write A0–A17 to FIFOA–B
↑
L
L
X
H
Active
Read FIFOB–A to A0–A17
PORT B
SELECT INPUTS
B0 B17
B0–B17
PORT B OPERATION
PORT-B
X
High Z
None
H
X
High Z
Write B0–B17 to FIFOB–A
X
H
Active
Read FIFOA–B to B0–B17
CLKB
CSB
W/RB
WENB
RENB
X
H
X
X
↑
L
H
↑
L
L
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3
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
logic symbol†
CLKA
CSA
W/RA
76
&
80
OE1
79
77
&
RENA
75
1
RSTA
PENA
IRA
ORA
HFA
AF/AEA
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16
A17
2
5
74
4
3
7
Clock B
&
CLKB
65
OE2
66
Write
Enable
FIFOA–B
Write
Enable
FIFOB–A
&
Read
Enable
FIFOB–A
Read
Enable
FIFOA–B
&
Reset FIFOA–B
Program Enable
FIFOA–B
Input-Ready
Port A
Output-Ready
Port A
Half-Full
FIFOA–B
Almost-Full/Empty
FIFOA–B
68
70
Reset FIFOB–A
Program Enable
FIFOB–A
Input–Ready
Port B
Output–Ready
Port B
Half–Full
FIFOB–A
Almost–Full/Empty
FIFOB–A
0
0
8
64
63
60
71
61
62
58
57
10
55
11
54
13
52
14
51
16
49
17
48
19
1
20
46
2
Data
45
Data
22
43
23
42
25
40
26
39
28
37
29
36
31
34
32
33
17
17
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Terminal numbers are for the PH package.
4
69
CSB
W/RB
&
WENA
Φ
FIFO 512 × 18 × 2
SN74ABT7819A
Clock A
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WENB
RENB
RSTB
PENB
IRB
ORB
HFB
AF/AEB
B0
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
B12
B13
B14
B15
B16
B17
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
functional block diagram
PENA
RENA
WENA
CSA
W/RA
CLKA
RSTA
Port-A
Control
Logic
Read
Pointer
18
Register
512 × 18
Dual-Port SRAM
FIFOB–A
Register
18
18
Write
Pointer
Flag
Logic
FIFOB–A
ORA
IRB
AF/AEB
HFB
8
A0–A17
B0–B17
8
IRA
AF/AEA
HFA
Flag
Logic
FIFOA–B
ORB
Write
Pointer
18
Register
512 × 18
Dual-Port SRAM
FIFOA–B
Register
Read
Pointer
Port-B
Control
Logic
RSTB
CLKB
CSB
W/RB
WENB
RENB
PENB
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5
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
enable logic diagram (positive logic)
CSA
W/RA
WENA
WEN FIFOA–B
A0–A17 (output enable)
REN FIFOB–A
RENA
CSB
W/RB
WENB
WEN FIFOB–A
B0–B17 (output enable)
REN FIFOA–B
RENB
Terminal Functions
TERMINAL†
NAME
NO.
A0–A17
7, 8, 10, 11,
13, 14, 16, 17,
19, 20, 22, 23,
25, 26, 28, 29,
31, 32
AF/AEA
3
I/O
DESCRIPTION
I/O
Port-A data. The 18-bit bidirectional data port for side A.
O
FIFOA–B almost-full/almost-empty flag. Depth offsets can be programmed for AF/AEA or the default
value of 128 can be used for both the almost-empty offset (X) and the almost-full offset (Y). AF/AEA is
high when X or fewer words or (512 – Y) or more words are stored in FIFOA–B. AF/AEA is forced high
when FIFOA–B is reset.
AF/AEB
62
O
FIFOB–A almost-full/almost-empty flag. Depth offsets can be programmed for AF/AEB or the default
value of 128 can be used for both the almost-empty offset (X) and the almost-full offset (Y). AF/AEB is
high when X or fewer words or (512 – Y) or more words are stored in FIFOB–A. AF/AEB is forced high
when FIFOB–A is reset.
B0–B17
58, 57, 55, 54,
52, 51, 49, 48,
46, 45, 43, 42,
40, 39, 37, 36,
34, 33
I/O
Port-B data. The 18-bit bidirectional data port for side B.
CLKA
76
I
Port-A clock. CLKA is a continuous clock that synchronizes all data transfers through port A to its
low-to-high transition and can be asynchronous or coincident to CLKB.
CLKB
69
I
Port-B clock. CLKB is a continuous clock that synchronizes all data transfers through port B to its
low-to-high transition and can be asynchronous or coincident to CLKA.
CSA
80
I
Port-A chip select. CSA must be low to enable a low-to-high transition of CLKA to either write data from
A0–A17 to FIFOA–B or read data from FIFOB–A to A0–A17. The A0–A17 outputs are in the
high-impedance state when CSA is high.
CSB
65
I
Port-B chip select. CSB must be low to enable a low-to-high transition of CLKB to either write data from
B0–B17 to FIFOB–A or read data from FIFOA–B to B0–B17. The B0–B17 outputs are in the
high-impedance state when CSB is high.
† Terminal numbers are for the PH package.
6
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• DALLAS, TEXAS 75265
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
Terminal Functions (Continued)
TERMINAL†
NAME
NO.
I/O
DESCRIPTION
HFA
4
O
FIFOA–B half-full flag. HFA is high when FIFOA–B contains 256 or more words and is low when
FIFOA–B contains 255 or fewer words. HFA is set low after FIFOA–B is reset.
HFB
61
O
FIFOB–A half-full flag. HFB is high when FIFOB–A contains 256 or more words and is low when
FIFOB–A contains 255 or fewer words. HFB is set low after FIFOB–A is reset.
IRA
5
O
Port-A input-ready flag. IRA is synchronized to the low-to-high transition of CLKA. When IRA is low,
FIFOA–B is full and writes to its array are disabled. IRA is set low during a FIFOA–B reset and is set high
on the second low-to-high transition of CLKA after reset.
IRB
60
O
Port-B input-ready flag. IRB is synchronized to the low-to-high transition of CLKB. When IRB is low,
FIFOB–A is full and writes to its array are disabled. IRB is set low during a FIFOB–A reset and is set high
on the second low-to-high transition of CLKB after reset.
O
Port-A output-ready flag. ORA is synchronized to the low-to-high transition of CLKA. When ORA is low,
FIFOB–A is empty and reads from its array are disabled. The last valid word remains on the FIFOB–A
outputs when ORA is low. Ready data is present for the A0–A17 outputs when ORA is high. ORA is set
low during a FIFOB–A reset and goes high on the third low-to-high transition of CLKA after the first word
is loaded to an empty FIFOB–A.
ORA
74
ORB
71
O
Port-B output-ready flag. ORB is synchronized to the low-to-high transition of CLKB. When ORB is low,
FIFOA–B is empty and reads from its array are disabled. The last valid word remains on the FIFOA–B
outputs when ORB is low. Ready data is present for the B0–B17 outputs when ORB is high. ORB is set
low during a FIFOA–B reset and goes high on the third low-to-high transition of CLKB after the first word
is loaded to an empty FIFOA–B.
PENA
2
I
AF/AEA program enable. After FIFOA–B is reset and before a word is written to its array, the binary value
on A0–A7 is latched as an AF/AEA offset when PENA is low and CLKA is high.
PENB
63
I
AF/AEB program enable. After FIFOB–A is reset and before a word is written to its array, the binary value
on B0–B7 is latched as an AF/AEB offset when PENB is low and CLKB is high.
RENA
75
I
Port-A read enable. A high level on RENA enables data to be read from FIFOB–A on the low-to-high
transition of CLKA when CSA is low, W/RA is low, and ORA is high.
RENB
70
I
Port-B read enable. A high level on RENB enables data to be read from FIFOA–B on the low-to-high
transition of CLKB when CSB is low, W/RB is low, and ORB is high.
RSTA
1
I
FIFOA–B reset. To reset FIFOA–B, four low-to-high transitions of CLKA and four low-to-high transitions
of CLKB must occur while RSTA is low. This sets HFA low, IRA low, ORB low, and AF/AEA high.
RSTB
64
I
FIFOB–A reset. To reset FIFOB–A, four low-to-high transitions of CLKA and four low-to-high transitions
of CLKB must occur while RSTB is low. This sets HFB low, IRB low, ORA low, and AF/AEB high.
WENA
77
I
Port-A write enable. A high level on WENA enables data on A0–A17 to be written into FIFOA–B on the
low-to-high transition of CLKA when W/RA is high, CSA is low, and IRA is high.
WENB
68
I
Port-B write enable. A high level on WENB enables data on B0–B17 to be written into FIFOB–A on the
low-to-high transition of CLKB when W/RB is high, CSB is low, and IRB is high.
I
Port-A write/read select. A high on W/RA enables A0–A17 data to be written to FIFOA–B on a low-to-high
transition of CLKA when WENA is high, CSA is low, and IRA is high. A low on W/RA enables data to be
read from FIFOB–A on a low-to-high transition of CLKA when RENA is high, CSA is low, and ORA is high.
The A0–A17 outputs are in the high-impedance state when W/RA is high.
I
Port-B write/read select. A high on W/RB enables B0–B17 data to be written to FIFOB–A on a low-to-high
transition of CLKB when WENB is high, CSB is low, and IRB is high. A low on W/RB enables data to be
read from FIFOA–B on a low-to-high transition of CLKB when RENB is high, CSB is low, and ORB is high.
The B0–B17 outputs are in the high-impedance state when W/RB is high.
W/RA
W/RB
79
66
† Terminal numbers are for the PH package.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
7
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
CLKA
1
CLKB
1
2
3
2
4
3
1
2
4
RSTA
ÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎÎÎ
ÏÏÏÏÏ
ÏÏÏÏÏ
ÏÏÏÏÏ
IRA
ORB
HFA
AF/AEA
NOTE: FIFOB–A is reset in the same manner.
Figure 1. Reset Cycle for FIFOA–B
CLKA
1
IRA
0
CSA
ÌÌÌÌÌ
ÌÌÌÌÌÌÌ
ÌÌ
ÌÌÌÌÌ
ÌÌÌÌÌÌÌ
ÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌ ÌÌÌ ÌÌÌÌÌÌÌÌ ÌÌÌ ÌÌ
ÌÌÌÌÌÌ ÌÌÌ ÌÌÌÌÌÌÌÌ ÌÌÌ ÌÌ
W/RA
WENA
A0–A17
Word 1†
Word 2†
Word 3†
† Written to FIFOA–B
Figure 2. Write Timing – Port A
8
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Word 4†
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
CLKB
1
IRB
0
CSB
ÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌ
ÌÌÌ
ÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌ
ÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌ ÌÌÌ ÌÌÌÌÌÌÌÌ ÌÌÌ ÌÌÌ
ÌÌÌÌÌÌ ÌÌÌ ÌÌÌÌÌÌÌÌ ÌÌÌ ÌÌÌ
W/RB
WENB
B0–B17
Word 1†
Word 2†
Word 3†
Word 4†
† Written to FIFOB–A
Figure 3. Write Timing – Port B
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9
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
CLKA
1
CSA
0
1
W/RA
ÏÏÏÏÏÎÎÎÎÎ
ÏÏÏÏÏÎÎÎÎÎ
ÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
WENA
tsu
A0–A17
CLKB
W1
1
2
3
ORB
tpd
tpd
CSB
W/RB
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÎÎÎÎÎÎÎÎÎÎÎ
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÎÎÎÎÎÎÎÎÎÎÎ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
RENB
tpd
W1 From FIFOA–B
B0–B17
NOTE: Operation of FIFOB–A is identical to that of FIFOA–B.
Figure 4. ORB-Flag Timing and First Data-Word Fall Through When FIFOA–B Is Empty
10
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
0
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
CLKB
1
CSB
0
1
W/RB
RENB
0
ÏÏÏ ÎÎÎÎ
ÏÏÏ ÎÎÎÎ
From FIFOA–B
B0–B17
CLKA
1
2
IRA
tpd
tpd
1
CSA
0
WENA
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
1
W/RA
0
A0–A17
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
NOTE: Operation of FIFOB–A is identical to that of FIFOA–B.
ÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌ
To
FIFOA–B
Figure 5. Write-Cycle and IRA-Flag Timing When FIFOA–B Is Full
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
11
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
CLKA
1
ORA
0
CSA
ÎÎÎÎ
ÏÏÏÏÏÏÏ
ÎÎÎÎ
ÏÏÏÏÏÏÏ
ÎÎÎÎ
ÏÏÏÏÏÏÏ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
W/RA
RENA
tpd
ten
Word 1†
A0–A17
tdis
Word 2†
Word 3†
Word 4†
† Read from FIFOB–A
Figure 6. Read Timing – Port A
CLKB
1
ORB
0
CSB
ÎÎÎÎ
ÏÏÏÏÏÏÏ
ÎÎÎÎ
ÏÏÏÏÏÏÏ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
W/RB
RENB
ten
B0–B17
tpd
Word 1‡
tdis
Word 2‡
Word 3‡
‡ Read from FIFOA–B
Figure 7. Read Timing – Port B
12
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
Word 4‡
CLKA
WENA
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
IRA
A0–A17
W1
WX+1
WX+2
W256
W257
W512–Y
W513–Y
W513
RENB
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
• DALLAS, TEXAS 75265
ORB
B0–B17
W1
W2
WY+1
WY+2
W257
W258
W512–X
W513–X
AF/AEA
HFA
Figure 8. FIFOA–B (HFA, AF/AEA) Asynchronous Flag Timing
13
SCBS756 – MAY 2002
NOTES: A. CSA, CSB = 0, W/RA = 1, W/RB = 0
B. X is the almost-empty offset and Y is the almost-full offset for AF/AEA.
C. HFB and AF/AEB function in the same manner for FIFOB–A.
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
POST OFFICE BOX 655303
CLKB
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
offset values for AF/AE
The AF/AE flag of each FIFO has two programmable limits: the almost-empty offset value (X) and the almost-full
offset value (Y). They can be programmed from the input of the FIFO after it is reset and before a word is written
to its memory. An AF/AE flag is high when its FIFO contains X or fewer words or (512 – Y) or more words.
To program the offset values for AF/AEA, PENA is brought low after FIFOA–B is reset and only when CLKA is
low. On the following low-to-high transition of CLKA, the binary value on A0–A7 is stored as the almost-empty
offset value (X) and the almost-full offset value (Y). Holding PENA low for another low-to-high transition of CLKA
reprograms Y to the binary value on A0–A7 at the time of the second CLKA low-to-high transition.
During the first two CLKA cycles used for offset programming, PENA can be brought high only when CLKA is
low. PENA can be brought high at any time after the second CLKA pulse used for offset programming returns
low. A maximum value of 255 can be programmed for either X or Y (see Figure 9). To use the default values
of X = Y = 128, PENA must be tied high. No data is stored in FIFOA–B while the AF/AEA offsets are programmed.
The AF/AEB flag is programmed in the same manner, with PENB enabling CLKB to program the offset values
taken from B0–B7.Figure 8
RESET
CLKA
3
4
IRA
PENA
CSA
W/RA
WENA
A0–A7
ÏÏÏÏÏÏÏ
ÎÎÎ
ÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏ
ÎÎÎ
ÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏÏÏÏÏÏ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌÌÌÌÌÌ
ÌÌÌÌÌÌÌÌÌ
X and Y
Y
Figure 9. Programming X and Y Separately for AF/AEA
14
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Input voltage range, VI (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to VCC + 0.5 V
Voltage range applied to any output in the high state or power-off state, VO . . . . . . . . . . . . . . –0.5 V to 5.5 V
Current into any output in the low state, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 mA
Input clamp current, IIK (VI < 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –18 mA
Output clamp current, IOK (VO < 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –50 mA
Package thermal impedance, θJA (see Note 2): PH package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72°C/W
PN package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62°C/W
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
† 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 negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51–7.
recommended operating conditions
MIN
NOM
MAX
4.5
5
5.5
UNIT
VCC
VIH
Supply voltage
VIL
VI
Low-level input voltage
IOH
IOL
High-level output current
VCC
–12
mA
Low-level output current
24
mA
∆t/∆v
Input transition rise or fall rate
5
ns/V
TA
Operating free-air temperature
70
°C
High-level input voltage
2
V
0.8
Input voltage
V
0
0
V
V
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
VIK
TEST CONDITIONS
VCC = 4.5 V,
VCC = 4.5 V,
II = –18 mA
IOH = –3 mA
VOH
VCC = 5 V,
VCC = 4.5 V,
IOH = –3 mA
IOH = –12 mA
VOL
II
VCC = 4.5 V,
VCC = 5.5 V,
IOL = 24 mA
VI = VCC or GND
IOZH§
IOZL§
VCC = 5.5 V,
VCC = 5.5 V,
VO = 2.7 V
VO = 0.5 V
IO¶
VCC = 5.5 V,
VO = 2.5 V
Outputs high
VCC = 5.5
5 5 V,
V IO = 0
0,
VI = VCC or GND
ICC
Ci
Control inputs
Cio
A or B ports
MIN
TYP‡
MAX
UNIT
–1.2
V
2.5
V
3
2
0.5
–40
–100
µA
50
µA
–50
µA
–180
mA
15
Outputs low
95
Outputs disabled
VI = 2.5 V or 0.5 V
VO = 2.5 V or 0.5 V
V
±1
mA
15
12
pF
14
pF
‡ All typical values are at VCC = 5 V, TA = 25°C.
§ The parameters IOZH and IOZL include the input leakage current.
¶ Not more than one output should be tested at a time, and the duration of the test should not exceed one second.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
15
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
timing requirements over recommended operating free-air temperature range (unless otherwise
noted) (see Figures 1 through 10)
fclock
Clock frequency
tw
Pulse
duration
tsu
th
Setup
time
Hold
time
’7819A-10
’7819A-12
’7819A-15
’7819A-20
’7819A-30
MIN
MIN
MIN
MIN
MIN
MAX
100
CLKA, CLKB high or low
MAX
80
67
MAX
50
4.5
6
8
11
A0–A17 before CLKA↑ and
B0–B17 before CLKB↑
2
3
4
5
5
CSA before CLKA↑ and
CSB before CLKB↑
6
6
6
7
7
W/RA before CLKA↑ and
W/RB before CLKB↑
6
6
6
7
7
WENA before CLKA↑ and
WENB before CLKB↑
4
4
4
5
5
RENA before CLKA↑ and
RENB before CLKB↑
5
5
5
5
6
PENA before CLKA↑ and
PENB before CLKB↑
3
3
4
5
5
RSTA or RSTB low before
first CLKA↑ and CLKB↑†
3
3
4
5
5
A0–A17 after CLKA↑ and
B0–B17 after CLKB↑
0
0
0
0
0
CSA after CLKA↑ and
CSB after CLKB↑
0
0
0
0
0
W/RA after CLKA↑ and
W/RB after CLKB↑
0
0
0
0
0
WENA after CLKA↑ and
WENB after CLKB↑
0
0
0
0
0
RENA after CLKA↑ and
RENB after CLKB↑
0
0
0
0
0
PENA after CLKA low and
PENB after CLKB low
2
2
2
2
2
RSTA or RSTB low after
fourth CLKA↑ and CLKB↑†
3
3
3
4
4
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
MAX
33.3
4.5
† To permit the clock pulse to be utilized for reset purposes
16
MAX
UNIT
MHz
ns
ns
ns
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
switching characteristics over recommended ranges of supply voltage and operating free-air
temperature, CL = 50 pF (unless otherwise noted) (see Figure 10)
PARAMETER
fmax
tpd
d
tpd‡
tpd
d
FROM
(INPUT)
CLKA
or
CLKB
tPLH
MIN
80
67
MAX
50
MAX
33.3
6
8
4
9
4
10
4
12
4
14
6
8
4
9
4
10
4
12
4
14
CLKA↑
A0–A17
5
CLKB↑
B0–B17
5
CLKA↑
IRA
4
9
4
9
4
10
4
12
4
14
IRB
4
9
4
9
4
10
4
12
4
14
CLKA↑
ORA
3.5
9
3.5
9
3.5
10
3.5
12
3.5
14
CLKB↑
ORB
3.5
9
3.5
9
3.5
10
3.5
12
3.5
14
8
17
8
17
8
17
8
18
8
20
8
17
8
17
8
17
8
18
8
20
4
12
4
12
4
14
4
15
4
16
8
17
8
17
8
17
8
18
8
20
8
17
8
17
8
17
8
18
8
20
RSTA
CLKA↑
CLKB↑
AF/AEA
AF/AEB
RSTB
AF/AEB
4
12
4
12
4
14
4
15
4
16
CLKA↑
HFA
8
17
8
17
8
17
8
18
8
20
8
17
8
17
8
17
8
18
8
20
4
12
4
12
4
14
4
15
4
16
8
17
8
17
8
17
8
18
8
20
8
17
8
17
8
17
8
18
8
20
4
12
4
12
4
14
4
15
4
16
2.5
8
2.5
8
2.5
9
2.5
10
2.5
11
2.5
8
2.5
8
2.5
9
2.5
10
2.5
11
2.5
8
2.5
8
2.5
9
2.5
10
2.5
11
2.5
8
2.5
8
2.5
9
2.5
10
2.5
11
2.5
8
2.5
8
2.5
9
2.5
10
2.5
11
2.5
8
2.5
8
2.5
9
2.5
10
2.5
11
2.5
8
2.5
8
2.5
9
2.5
10
2.5
11
2.5
8
2.5
9
2.5
10
2.5
11
RSTA
CLKB↑
RSTB
W/RA
CSB
CSA
W/RA
CSB
HFA
HFB
HFB
A0 A17
A0–A17
B0 B17
B0–B17
A0 A17
A0–A17
B0 B17
B0–B17
ns
ns
CLKB↑
AF/AEA
UNIT
MHz
3
W/RB
tdis
di
’7819A-30
MIN
MAX
3
CSA
ten
’7819A-20
MIN
MAX
B0–B17
CLKA↑
tPLH
tPHL
’7819A-15
MIN
A0–A17
CLKB↑
tPHL
100
’7819A-12
CLKB↑
CLKB↑
tpd
d
’7819A-10
MIN TYP† MAX
CLKA↑
CLKA↑
tPLH
TO
(OUTPUT)
W/RB
2.5
8
† All typical values are at VCC = 5 V, TA = 25°C.
‡ This parameter is measured with a 30-pF load (see Figure 11).
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
ns
ns
ns
ns
ns
ns
ns
17
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
PARAMETER MEASUREMENT INFORMATION
7V
PARAMETER
S1
ten
500 Ω
From Output
Under Test
Test
Point
CL = 50 pF
(see Note A)
tdis
tpd
500 Ω
S1
tPZH
tPZL
tPHZ
tPLZ
tPLH
tPHL
Open
Closed
Open
Closed
Open
Open
tw
LOAD CIRCUIT
3V
3V
Timing
Input
Input
1.5 V
0V
1.5 V
0V
tsu
VOLTAGE WAVEFORMS
PULSE DURATION
th
3V
Data
Input
1.5 V
3V
1.5 V
0V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
Output
Control
1.5 V
0V
3V
1.5 V
1.5 V
0V
tPLH
Output
≈3.5 V
Output
Waveform 1
S1 at 7 V
1.5 V
VOH
1.5 V
VOL
Output
Waveform 2
S1 at Open
1.5 V
Figure 10. Load Circuit and Voltage Waveforms
• DALLAS, TEXAS 75265
VOL
VOH
≈0 V
NOTE A: CL includes probe and jig capacitance.
POST OFFICE BOX 655303
VOH – 0.3 V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
18
VOL + 0.3 V
tPHZ
tPZH
tPHL
1.5 V
1.5 V
tPLZ
tPZL
Input
1.5 V
SN74ABT7819A
512 × 18 × 2
CLOCKED BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCBS756 – MAY 2002
TYPICAL CHARACTERISTICS
PROPAGATION DELAY TIME
vs
LOAD CAPACITANCE
VCC = 5 V
TA = 25°C
RL = 500 Ω
typ + 4
typ + 2
typ
typ – 2
0
50
100
150
200
250
300
CL – Load Capacitance – pF
Figure 11
SUPPLY CURRENT
vs
CLOCK FREQUENCY
160
140
I CC(f) – Supply Current – mA
t pd – Propagation Delay Time – ns
typ + 6
120
TA = 75°C
CL = 0 pF
VCC = 5.5 V
VCC = 5 V
100
80
VCC = 4.5 V
60
40
20
10 15 20 25 30 35 40 45
50 55 60 65 70
fclock – Clock Frequency – MHz
Figure 12
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
19
PACKAGE OPTION ADDENDUM
www.ti.com
25-Feb-2005
PACKAGING INFORMATION
Orderable Device
Status (1)
SN74ABT7819A-10PH
SN74ABT7819A-10PN
SN74ABT7819A-12PH
SN74ABT7819A-12PN
Pins Package Eco Plan (2)
Qty
Lead/Ball Finish
MSL Peak Temp (3)
Package
Type
Package
Drawing
ACTIVE
QFP
PH
80
66
None
A42
Level-3-220C-168 HR
ACTIVE
LQFP
PN
80
119
None
CU NIPDAU
Level-3-220C-168 HR
ACTIVE
QFP
PH
80
66
None
A42
Level-3-220C-168 HR
ACTIVE
LQFP
PN
80
119
None
CU NIPDAU
Level-3-220C-168 HR
SN74ABT7819A-15PH
ACTIVE
QFP
PH
80
66
None
A42
Level-3-220C-168 HR
SN74ABT7819A-15PN
ACTIVE
LQFP
PN
80
119
None
CU NIPDAU
Level-3-220C-168 HR
SN74ABT7819A-20PH
ACTIVE
QFP
PH
80
66
None
A42
Level-3-220C-168 HR
SN74ABT7819A-20PN
ACTIVE
LQFP
PN
80
119
None
CU NIPDAU
Level-3-220C-168 HR
SN74ABT7819A-30PH
ACTIVE
QFP
PH
80
66
None
A42
Level-3-220C-168 HR
SN74ABT7819A-30PN
ACTIVE
LQFP
PN
80
119
None
CU NIPDAU
Level-3-220C-168 HR
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - May not be currently available - please check http://www.ti.com/productcontent for the latest availability information and additional
product content details.
None: Not yet available Lead (Pb-Free).
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Green (RoHS & no Sb/Br): TI defines "Green" to mean "Pb-Free" and in addition, uses package materials that do not contain halogens,
including bromine (Br) or antimony (Sb) above 0.1% of total product weight.
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDECindustry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 1
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,
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Following are URLs where you can obtain information on other Texas Instruments products and application
solutions:
Products
Applications
Amplifiers
amplifier.ti.com
Audio
www.ti.com/audio
Data Converters
dataconverter.ti.com
Automotive
www.ti.com/automotive
DSP
dsp.ti.com
Broadband
www.ti.com/broadband
Interface
interface.ti.com
Digital Control
www.ti.com/digitalcontrol
Logic
logic.ti.com
Military
www.ti.com/military
Power Mgmt
power.ti.com
Optical Networking
www.ti.com/opticalnetwork
Microcontrollers
microcontroller.ti.com
Security
www.ti.com/security
Telephony
www.ti.com/telephony
Video & Imaging
www.ti.com/video
Wireless
www.ti.com/wireless
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