TI SN74ACT7802

SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
D
D
D
D
D
D
Member of the Texas Instruments
Widebus Family
Low-Power Advanced CMOS Technology
Load and Unload Clocks Can Be
Asynchronous or Coincident
1024 Words × 18 Bits
Programmable Almost-Full/Almost-Empty
Flag
Empty, Full, and Half-Full Flags
D
D
D
D
D
D
Fast Access Times of 30 ns With a 50-pF
Load
Fall-Through Time Is 20 ns Typical
Data Rates up to 40 MHz
High-Output Drive for Direct Bus Interface
3-State Outputs
Package Options Include 68-Pin (FN) and
80-Pin Thin Quad Flat (PN) Packages
D15
D16
D17
GND
UNCK
NC
NC
OE
RESET
VCC
GND
EMPTY
VCC
Q17
Q16
GND
Q15
FN PACKAGE
(TOP VIEW)
9
10
8 7
6
5 4 3 2 1 68 67 66 65 64 63 62 61
60
11
59
12
58
13
57
14
56
15
55
16
54
17
53
18
52
19
51
20
50
21
49
22
48
23
47
24
46
25
45
VCC
Q14
Q13
GND
Q12
Q11
VCC
Q10
Q9
GND
Q8
Q7
VCC
Q6
Q5
GND
Q4
Q0
Q1
GND
Q2
Q3
VCC
AF/AE
GND
FULL
HF
VCC
26
44
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
DAF
GND
LDCK
NC
NC
VCC
D14
D13
D12
D11
D10
D9
VCC
D8
GND
D7
D6
D5
D4
D3
D2
D1
D0
NC – No internal connection
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 Incorporated.
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.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
1
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
GND
GND
Q4
Q15
VCC
Q14
Q13
GND
GND
Q12
Q11
VCC
Q10
Q9
GND
Q8
Q7
VCC
Q6
Q5
PN PACKAGE
(TOP VIEW)
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61
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
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
VCC
VCC
NC
Q3
Q2
GND
Q1
Q0
VCC
HF
FULL
GND
GND
AF/AE
VCC
NC
NC
LDCK
GND
NC
D8
GND
D7
D6
D5
D4
D3
D2
D1
D0
DAF
NC
1
NC
D14
D13
D12
D11
D10
D9
V CC
NC
GND
GND
Q16
Q17
VCC
EMPTY
GND
VCC
RESET
OE
NC
NC
UNCK
GND
D17
D16
D15
NC
NC
NC – No internal connection
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 SN74ACT7802 is a 1024-word by 18-bit FIFO for high-speed applications. It processes data
in a bit-parallel format at rates up to 40 MHz and access times of 30 ns.
Data is written into the FIFO memory on a low-to-high transition on the load-clock (LDCK) input and is read out
on a low-to-high transition on the unload-clock (UNCK) input. The memory is full when the number of words
clocked in exceeds by 1024 the number of words clocked out. When the memory is full, LDCK has no effect on
the data in the memory; when the memory is empty, UNCK has no effect.
A low level on the reset (RESET) input resets the FIFO internal clock stack pointers and sets full (FULL) high,
almost full/almost empty (AF/AE) high, half full (HF) low, and empty (EMPTY) low. The Q outputs are not reset
to any specific logic level. The FIFO must be reset upon power up. The Q outputs are noninverting and are in
the high-impedance state when the output-enable (OE) input is low.
When writing to the FIFO after a reset pulse or when the FIFO is empty, the first active transition on LDCK drives
EMPTY high and causes the first word written to the FIFO to appear on the Q outputs. An active transition on
UNCK is not required to read the first word written to the FIFO. Each subsequent read from the FIFO requires
an active transition on UNCK.
The SN74ACT7802 can be cascaded in the word-width direction but not in the word-depth direction.
The SN74ACT7802 is characterized for operation from 0°C to 70°C.
2
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SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
logic symbol†
Φ
FIFO 1024 × 18
SN74ACT7802
RESET
LDCK
UNCK
OE
DAF
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
D16
D17
1
RESET
29
5
2
LDCK
FULL
UNCK
HALF FULL
26
ALMOST FULL/EMPTY
EN1
27
DEF ALMOST FULL
EMPTY
0
0
35
36
33
66
38
25
39
24
41
23
42
22
44
21
46
20
47
19
49
17
50
Data
15
Data
1
52
14
53
13
55
12
56
11
58
10
59
9
61
8
63
7
64
17
17
FULL
HF
AF/AE
EMPTY
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
Q8
Q9
Q10
Q11
Q12
Q13
Q14
Q15
Q16
Q17
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the FN package.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
3
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
functional block diagram
OE
D0–D17
LDCK
Write
Control
UNCK
Read
Control
Location 1
Read
Pointer
Location 2
1024 × 18 RAM
Write
Pointer
Location 1023
Location 1024
Q0–Q17
Reset
Logic
RESET
StatusFlag
Logic
EMPTY
FULL
HF
DAF
AF/AE
Terminal Functions
TERMINAL
I/O
DESCRIPTION
33
O
Almost-full/almost-empty flag. Depth-offset values can be programmed for AF/AE, or the default value
of 256 can be used for the almost-empty almost-full offset (X). AF/AE is high when memory contains X
or fewer words or (1024 – X) or more words. AF/AE is high after reset.
27
I
Define almost-full flag. The high-to-low transition of DAF stores the binary value of data inputs as the
AF/AE offset value (X). With DAF held low, a low pulse on RESET defines AF/AE using X.
D0–D17
7–15, 17,
19–26
I
18-bit data input port
EMPTY
66
O
Empty flag. EMPTY is low when the FIFO is empty. A FIFO reset also causes EMPTY to go low.
FULL
35
O
Full flag. FULL is low when the FIFO is full. A FIFO reset causes FULL to go high.
HF
36
O
Half-full flag. HF is high when the FIFO memory contains 512 or more words. HF is low after reset.
LDCK
29
I
Load clock. Data is written to the FIFO on the rising edge of LDCK when FULL is high.
NAME
NO.†
AF/AE
DAF
OE
2
I
Output enable. When OE is low, the data outputs are in the high-impedance state.
Q0–Q17
38–39, 41–42,
44, 46–47,
49–50, 52–53,
55–56, 58–59,
61, 63–64
O
18-bit data-output port
RESET
1
I
Reset. A low level on RESET resets the FIFO and drives AF/AE and FULL high and HF and EMPTY low.
UNCK
5
I
Unload clock. Data is read from the FIFO on the rising edge of UNCK when EMPTY is high.
† Terminal numbers listed are for the FN package.
4
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SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
offset value values for AF/AE
The FIFO memory status is monitored by the FULL, EMPTY, HF, and AF/AE flags. The FULL output is low when
the memory is full; the EMPTY output is low when the memory is empty. The HF output is high when the memory
contains 512 or more words and low when it contains fewer than 512 words. The level of the AF/AE flag is
determined by both the number of words in the FIFO and a user-definable offset X. AF/AE is high when the FIFO
is almost full or almost empty, i.e., when it contains X or fewer words or (1024 – X) or more words. The AF/AE
offset value is either user-defined or the default value of 256; it is programmed during each reset cycle as follows:
user-defined X:
Take DAF from high to low.
If RESET is not already low, take RESET low.
With DAF held low, take RESET high. This defines the AF/AE flag using X.
default X:
To redefine the AF/AE flag using the default value of X = 256, hold DAF high during the reset cycle.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
5
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LDCK
D0–D17
X
W1
W2
WX+1
W512
W1024–X
Don’t Care
W1024
OE
• DALLAS, TEXAS 75265
Q0–Q17
W1
W2
WX+1
WX+2
W513
W514
W1024–X
W1025–X W1023
W1024
ÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎ
POST OFFICE BOX 655303
UNCK
EMPTY
AF/AE
HF
FULL
Define the AF/AE Offset Value (X)
Using the Data on D0 – D8
Define the AF/AE Offset Value (X)
Using the Default Value of 256
Figure 1. Write, Read, and Flag Timing Reference
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
DAF
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
6
RESET
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Voltage range applied to a disabled 3-state output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 5.5 V
Package thermal impedance, θJA (see Note 1): FN package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39°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.
NOTE 1: The package thermal impedance is calculated in accordance with JESD 51.
recommended operating conditions
’ACT7802-25
’ACT7802-40
’ACT7802-60
MIN
MAX
MIN
MAX
MIN
MAX
4.5
5.5
4.5
5.5
4.5
5.5
UNIT
VCC
VIH
Supply voltage
VIL
IOH
Low-level input voltage
0.8
0.8
0.8
V
High-level output current
–8
–8
–8
mA
IOL
TA
Low-level output current
16
16
16
mA
70
°C
High-level input voltage
2
Operating free-air temperature
0
2
70
0
2
70
0
V
V
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
VOH
VOL
VCC = 4.5 V,
VCC = 4.5 V,
IOH = –8 mA
IOL = 16 mA
II
IOZ
VCC = 5.5 V,
VCC = 5.5 V,
VI = VCC or 0
VO = VCC or 0
ICC§
∆ICC§
VI = VCC – 0.2 V or 0
VCC = 5.5 V,
Ci
VI = 0,
VO = 0,
Co
One input at 3.4 V,
MIN
TYP‡
MAX
2.4
UNIT
V
Other inputs at VCC or GND
0.5
V
±5
µA
±5
µA
400
µA
1
mA
f = 1 MHz
4
pF
f = 1 MHz
8
pF
‡ All typical values are at VCC = 5 V, TA = 25°C.
§ ICC tested with outputs open
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7
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
timing requirements over recommended operating conditions (see Figures 1 and 2)
’ACT7802-25
MIN
fclock
tw
Clock frequency
Pulse duration
tsu
th
Setup time
Hold time
MAX
’ACT7802-40
MIN
40
MAX
’ACT7802-60
MIN
25
MAX
16.7
LDCK high or low
10
14
20
UNCK high or low
10
14
20
DAF high
10
10
10
RESET low
20
25
25
D0–D7 before LDCK↑
4
5
5
RESET inactive (high) before LDCK↑
5
5
5
Define AF/AE: D0–D8 before DAF↓
5
5
5
Define AF/AE: DAF↓ before RESET↑
7
7
7
Define AF/AE (default): DAF high before RESET↑
5
5
5
D0–D7 after LDCK↑
1
2
2
Define AF/AE: D0–D8 after DAF↓
0
0
0
Define AF/AE: DAF low after RESET↑
0
0
0
Define AF/AE (default): DAF high after RESET↑
0
0
0
UNIT
MHz
ns
ns
ns
switching characteristics over recommended ranges of supply voltage and operating free-air
temperature, CL = 50 pF (see Figures 1 and 2)
FROM
(INPUT)
fmax
LDCK or UNCK
40
LDCK↑
8
tpd
d
tpd‡
tPLH
TO
(OUTPUT)
’ACT7802-25
MIN TYP†
MAX
PARAMETER
Any Q
UNCK↑
UNCK↑
Any Q
LDCK↑
EMPTY
UNCK↑
tPHL
EMPTY
RESET↓
LDCK↑
tPLH
tpd
d
FULL
UNCK↑
FULL
RESET↓
LDCK↑
AF/AE
UNCK↑
’ACT7802-40
MIN
MAX
25
20
12
’ACT7802-60
MIN
MAX
16.7
UNIT
MHz
30
8
35
8
45
30
12
35
12
45
21
ns
ns
4
18
4
20
4
22
2
18
2
20
2
22
2
18
2
20
2
22
4
18
4
20
4
22
4
17
4
19
4
21
2
17
2
19
2
21
2
20
2
22
2
24
2
20
2
22
2
24
ns
ns
ns
ns
RESET↓
AF/AE
2
17
2
19
2
21
LDCK↑
HF
2
18
2
20
2
22
2
18
2
20
2
22
2
17
2
19
2
21
Any Q
2
12
2
14
2
16
ns
OE
Any Q
† All typical values are at VCC = 5 V, TA = 25°C.
‡ This parameter is measured with CL = 30 pF (see Figure 3).
2
14
2
16
2
18
ns
tPLH
tPHL
ten
tdis
UNCK↑
HF
RESET↓
OE
ns
ns
operating characteristics, VCC = 5 V, TA = 25°C
PARAMETER
Cpd
8
TEST CONDITIONS
Power dissipation capacitance per channel
POST OFFICE BOX 655303
CL = 50 pF,
• DALLAS, TEXAS 75265
f = 5 MHz
TYP
65
UNIT
pF
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
PARAMETER MEASUREMENT INFORMATIONFigure 1
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
Input
0V
1.5 V
0V
tsu
VOLTAGE WAVEFORMS
PULSE DURATION
th
3V
Data
Input
1.5 V
1.5 V
0V
3V
Output
Control
tPZL
3V
1.5 V
1.5 V
1.5 V
0V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
1.5 V
0V
tPLH
1.5 V
1.5 V
tPZH
1.5 V
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
tPLZ
≈ 3.5 V
Output
Waveform 1
S1 at 7 V
tPHL
VOH
Output
1.5 V
3V
Timing
Input
Input
1.5 V
Output
Waveform 2
S1 at Open
VOL + 0.3 V
VOL
tPHZ
1.5 V
VOH
VOH – 0.3 V
≈0V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
NOTE A: CL includes probe and jig capacitance.
Figure 2. Load Circuit and Voltage Waveforms
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9
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
TYPICAL CHARACTERISTICS
POWER DISSIPATION CAPACITANCE
vs
SUPPLY VOLTAGE
PROPAGATION DELAY TIME
vs
LOAD CAPACITANCE
typ + 3
VCC = 5 V
RL = 500 Ω
TA = 25°C
typ + 6
Cpd – Power Dissipation Capacitance – pF
t pd – Propagation Delay Time – ns
typ + 8
typ + 4
typ + 2
typ
typ – 2
0
50
100
150
200
250
300
typ + 2
f = 5 MHz
TA = 25°C
CL = 50 pF
typ + 1
typ
typ – 1
typ – 2
typ – 3
4.5
4.6
Figure 3
Figure 4
POST OFFICE BOX 655303
5
5.1 5.2 5.3 5.4 5.5
VCC – Supply Voltage – V
CL – Load Capacitance – pF
10
4.7 4.8 4.9
• DALLAS, TEXAS 75265
SN74ACT7802
1024 × 18 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS187D – AUGUST 1990 – REVISED APRIL 1998
APPLICATION INFORMATION
SN74ACT7802
LDCK
LDCK
UNCK
FULL
EMPTY
EMPTY
FULL
OE
D18–D35
UNCK
D0–D17
Q0–Q17
OE
Q18–Q35
SN74ACT7802
LDCK
UNCK
EMPTY
FULL
OE
D0–D17
D0–D17
Q0–Q17
Q0–Q17
Figure 5. Word-Width Expansion: 1024 × 36 Bit
POST OFFICE BOX 655303
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11
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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
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Copyright  1999, Texas Instruments Incorporated