All rights reserved. Product specifications subject to change without notice.
OCTOBER 2005
DSC-2747/10
IDT72401/72403
CMOS PARALLEL FIFO 64 x 4, 64 x 5
MILITARY AND COMMERCIAL
TEMPERATURE RANGES
PIN CONFIGURATIONS
IDT72401/IDT72403
NC/OE
(1)
IR
SI
D
0
D
1
D
2
D
3
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Vcc
SO
OR
Q
0
Q
1
Q
2
Q
3
MR
2747 drw 02
PLASTIC DIP (P16-1, ORDER CODE: P)
CERDIP (D16-1, ORDER CODE: D)
SOIC (SO16-1, ORDER CODE: SO)
TOP VIEW
NOTE:
1. Pin 1: NC - No Connection IDT72401,
OE
- IDT72403
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
TERM
T
STG
I
OUT
Rating
Terminal Voltage with
Respect to GND
Storage Temp.
DC Output Current
Commercial
–0.5 to +7.0
–55 to +125
–50 to +50
Military
–0.5 to +7.0
–65 to +150
–50 to +50
Unit
V
°C
mA
RECOMMENDED OPERATING
CONDITIONS
Symbol
V
CC
GND
V
IH
V
IL
(1)
T
A
T
A
Parameter
Supply Voltage Commercial/Military
Supply Voltage
Input High Voltage
Input High Voltage
Operating Temperature Commercial
Operating Temperature Military
Min.
4.5
0
2.0
—
0
–55
Typ.
5.0
0
—
—
—
—
Max.
5.5
0
—
0.8
70
125
Unit
V
V
V
V
°C
°C
NOTE:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may
cause permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated in the
operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect reliability.
NOTE:
1. 1.5V undershoots are allowed for 10ns once per cycle.
DC ELECTRICAL CHARACTERISTICS
(Commercial: V
CC
= 5.0V ± 10%, T
A
= 0°C to +70°C; Military: V
CC
= 5.0V ± 10%, T
A
= –55°C to +125°C)
IDT72401
IDT72403
Commercial
f
IN
= 45, 35, 25, 15, 10 MHz
Symbol
I
IL
I
IH
V
OL
V
OH
I
OS
(1)
I
HZ
(2)
I
LZ
(2)
I
CC
(3,4)
Parameter
Low-Level Input Current
High-Level Input Current
Low-Level Output Voltage
High-Level Output Voltage
Output Short-Circuit Current
HIGH Impedance Output Current
LOW Impedance Output Current
Active Supply Current
Test Conditions
V
CC
= Max., GND
≤
V
I
≤
V
CC
V
CC
= Max., GND
≤
V
I
≤
V
CC
V
CC
= Min., I
OL
= 8mA
V
CC
= Min., I
OH
= –4mA
V
CC
= Max., V
O
= GND
V
CC
= Max., V
O
= 2.4V
V
CC
= Max., V
O
= 0.4V
V
CC
= Max., f = 10MHz
Min.
–10
—
—
2.4
–20
—
–20
—
Max.
—
10
0.4
—
–110
20
—
35
IDT72401
IDT72403
(5)
Military
f
IN
= 35, 25, 15, 10 MHz
Min.
–10
—
—
2.4
–20
—
–20
—
Max.
—
10
0.4
—
–110
20
—
45
Unit
µA
µA
V
V
mA
µA
µA
mA
NOTES:
1. Not more than one output should be shorted at a time and duration of the short-circuit should not exceed one second. Guaranteed but not tested.
2. IDT72403 only.
3. Tested with outputs open (I
OUT
= 0).
OE
is HIGH for IDT72403.
4. For frequencies greater than 10MHz, I
CC
= 35mA + (1.5mA x [f –10MHz]) commercial, and I
CC
= 45mA + (1.5mA x [f –10MHz]) military.
5. Military availability for IDT72403 is 10MHz, 35MHz. IDT72401 is available for all MHz.
2
IDT72401/72403
CMOS PARALLEL FIFO 64 x 4, 64 x 5
MILITARY AND COMMERCIAL
TEMPERATURE RANGES
OPERATING CONDITIONS
(Commercial: V
CC
= 5.0V ± 10%, T
A
= 0°C to +70°C; Military: V
CC
= 5.0V ± 10%, T
A
= –55°C to +125°C)
Commercial
IDT72401L45
IDT72403L45
Min.
Max.
9
—
11
0
13
9
11
20
10
3
13
0
—
—
—
—
—
—
—
—
—
—
IDT72401L35
IDT72403L35
Min.
Max.
9
—
17
0
15
9
17
25
10
3
15
0
—
—
—
—
—
—
—
—
—
—
Commercial and Military
(5)
IDT72401L25
IDT72401L15
IDT72403L25
IDT72403L15
Min.
Max.
Min.
Max.
11
—
11
—
24
0
20
11
24
25
10
5
20
0
—
—
—
—
—
—
—
—
—
—
25
0
30
11
25
25
25
5
30
0
—
—
—
—
—
—
—
—
—
—
IDT72401L10
IDT72403L10
Min.
Max.
11
—
30
0
40
11
25
30
35
5
30
0
—
—
—
—
—
—
—
—
—
—
Symbol
t
SIH
(1)
t
SIL
t
IDS
t
IDH
t
SOH
(1)
t
SOL
t
MRW
t
MRS
t
SIR
t
HIR
t
SOR
(4)
Parameter
Shift in HIGH Time
Shift in LOW TIme
Input Data Set-up
Input Data Hold Time
Shift Out HIGH Time
Shift Out LOW Time
Master Reset Pulse
Master Reset Pulse to SI
Data Set-up to IR
Data Hold from IR
Data Set-up to OR HIGH
Figure
2
2
2
2
5
5
8
8
4
4
7
Unit
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
AC ELECTRICAL CHARACTERISTICS
(Commercial: V
CC
= 5.0V ± 10%, T
A
= 0°C to +70°C; Military: V
CC
= 5.0V ± 10%, T
A
= –55°C to +125°C)
Commercial
IDT72401L45
IDT72403L45
Min.
Max.
—
—
—
—
—
—
5
—
—
—
—
—
—
—
9
9
45
18
18
45
18
19
—
19
30
25
25
20
12
12
—
—
IDT72401L35
IDT72403L35
Min.
Max.
—
—
—
—
—
—
5
—
—
—
—
—
—
—
9
9
35
18
20
35
18
20
—
20
34
28
28
20
15
12
—
—
Commercial and Military
(5)
IDT72401L25
IDT72401L15
IDT72403L25
IDT72403L15
Min.
Max.
Min.
Max.
—
—
—
—
—
—
5
—
—
—
—
—
—
—
11
11
25
21
28
25
19
34
—
34
40
35
35
25
20
15
—
—
—
—
—
—
—
—
5
—
—
—
—
—
—
—
11
11
15
35
40
15
35
40
—
40
65
35
35
35
30
25
—
—
IDT72401L10
IDT72403L10
Min.
Max.
—
—
—
—
—
—
5
—
—
—
—
—
—
—
11
11
10
40
45
10
40
55
—
55
65
40
40
40
35
30
—
—
Symbol
f
IN
t
IRL
(1)
t
IRH
(1)
f
OUT
t
ORL
(1)
t
ORH
(1)
t
ODH
t
ODS
t
PT
t
MRORL
t
MRIRH
t
MRQ
t
OOE
(3)
t
HZOE
(3,4)
t
IPH
(2,4)
t
OPH
(2,4)
Shift In Rate
Parameter
Shift In to Input Ready LOW
Shift In to Input Ready HIGH
Shift Out Rate
Shift Out to Output Ready LOW
Shift Out to Output Ready HIGH
Output Data Hold (Previous Word)
Output Data Shift (Next Word)
Data Throughput or "Fall-Through"
Master Reset to OR LOW
Master Reset to IR HIGH
Master Reset to Data Output LOW
Output Valid from
OE
LOW
Output High-Z from
OE
HIGH
Input Ready Pulse HIGH
Output Ready Pulse HIGH
Figure
2
2
2
5
5
5
5
5
4, 7
8
8
8
9
9
4
7
Unit
MHz
ns
ns
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
NOTES:
1. Since the FIFO is a very high-speed device, care must be excercised in the design of the hardware and timing utilized within the design. Device grounding and decoupling
are crucial to correct operation as the FIFO will respond to very small glitches due to long reflective lines, high capacitances and/or poor supply decoupling and grounding.
A monolithic ceramic capacitor of 0.1µF directly between V
CC
and GND with very short lead length is recommended.
2. This parameter applies to FIFOs communicating with each other in a cascaded mode. IDT FIFOs are guaranteed to cascade with other IDT FIFOs of like speed grades.
3. IDT72403 only.
4. Guaranteed by design but not currently tested.
5. Military availability for IDT72403 is 10MHz, 35MHz. IDT72401 is available for all MHz.
3
IDT72401/72403
CMOS PARALLEL FIFO 64 x 4, 64 x 5
MILITARY AND COMMERCIAL
TEMPERATURE RANGES
AC TEST CONDITIONS
Input Pulse Levels
Input Rise/Fall Times
Input Timing Reference Levels
Output Reference Levels
Output Load
GND to 3.0V
3ns
1.5V
1.5V
See Figure 1
ALL INPUT PULSES:
3.0V
GND
90%
10%
90%
10%
<3ns
<3ns
2747 drw 04
5V
1.1KΩ
CAPACITANCE
(T
A
= +25°C, f = 1.0MHz)
Symbol
C
IN
C
OUT
Parameter
Input Capacitance
Output Capacitance
Conditions
V
IN
= 0V
V
OUT
= 0V
Max.
5
7
Unit
pF
pF
OUTPUT
560Ω
30pF*
2747 drw 05
NOTE
:
1. Characterized values, not currently tested.
or equivalent circuit
Figure 1. AC Test Load
*Including scope and jig
SIGNAL DESCRIPTIONS
INPUTS:
DATA INPUT (D
0
-
3
)
Data input lines. The IDT72401 and IDT72403 have a 4-bit data input.
INPUT READY (IR)
When Input Ready is HIGH, the FIFO is ready for new input data to be written
to it. When IR is LOW the FIFO is unavailable for new input data. IR is also used
to cascade many FlFOs together, as shown in Figures 10 and 11.
OUTPUT READY (OR)
When Output Ready is HIGH, the output (Q
0
-
3
) contains valid data. When
OR is LOW, the FIFO is unavailable for new output data. OR is also used to
cascade many FlFOs together, as shown in Figures 10 and 11.
OUTPUT ENABLE (OE) (IDT72403 ONLY)
Output enable is used to read FIFO data onto a bus.
OE
is active LOW.
CONTROLS:
SHIFT IN (SI)
Shift In controls the input of the data into the FIFO. When SI is HIGH, data
can be written to the FIFO via the D
0
-
3
lines.
SHIFT OUT (SO)
Shift Out controls the output of data of the FIFO. When SO is HIGH, data can
be read from the FIFO via the Data Output (Q
0
-
3
) lines.
MASTER RESET (MR)
Master Reset clears the FIFO of any data stored within. Upon power up, the
FIFO should be cleared with a
MR. MR
is active LOW.
OUTPUTS:
DATA OUTPUT (Q
0
-
3
)
Data Output lines. The IDT72401 and IDT72403 have a 4-bit data output.
4
IDT72401/72403
CMOS PARALLEL FIFO 64 x 4, 64 x 5
MILITARY AND COMMERCIAL
TEMPERATURE RANGES
FUNCTIONAL DESCRIPTION
The 64 x 4 FIFO is designed using a dual port RAM architecture as opposed
to the traditional shift register approach. This FIFO architecture has a write
pointer, a read pointer and control logic, which allow simultaneous read and
write operations. The write pointer is incremented by the falling edge of the Shift
In (Sl) control; the read pointer is incremented by the falling edge of the Shift Out
(SO). The Input Ready (IR) signals when the FIFO has an available memory
location; Output Ready (OR) signals when there is valid data on the output.
Output Enable (OE) provides the capability of three-stating the FIFO outputs.
FIFO RESET
The FIFO must be reset upon power up using the Master Reset (MR) signal.
This causes the FlFO to enter an empty state, signified by Output Ready (OR)
being LOW and Input Ready (IR) being HIGH. In this state, the data outputs
(Q
0
-
3
) will be LOW.
DATA INPUT
Data is shifted in on the LOW-to-HlGH transition of Shift In (Sl). This loads
input data into the first word location of the FIFO and causes Input Ready (IR)
to go LOW. On the HlGH-to-LOW transition of SI, the write pointer is moved to
the next word position and IR goes HIGH, indicating the readiness to accept new
data. If the FIFO is full, IR will remain LOW until a word of data is shifted out.
DATA OUTPUT
Data is shifted out on the HlGH-to-LOW transition of Shift Out (SO). This causes
the internal read pointer to be advanced to the next word location. If data is
present, valid data will appear on the outputs and Output Ready (OR) will go
HIGH. If data is not present, OR will stay LOW indicating the FIFO is empty. The
last valid word read from the FIFO will remain at the FlFOs output when it is empty.
When the FIFO is not empty, OR goes LOW on the LOW-to-HIGH transition of
SO. Previous data remains on the output until the HIGH-to-LOW transition of
SO).
FALL THROUGH MODE
The FIFO operates in a fall-through mode when data gets shifted into an empty
FIFO. After a fall-through delay the data propagates to the output. When the
data reaches the output, the Output Ready (OR) goes HIGH. Fall-through mode
also occurs when the FIFO is completely full. When data is shifted out of the full
FIFO, a location is available for new data. After a fall-through delay, the Input
Ready (IR) goes HIGH. If Shift In (SI) is HIGH, the new data can be written
to the FIFO.
Since these FlFOs are based on an internal dual-port RAM architecture with
separate read and write pointers, the fall-through time (t
PT
) is one cycle long.
A word may be written into the FIFO on a clock cycle and can be accessed on
the next clock cycle.
1/f
IN
t
SIH
SI
t
SIL
1/f
IN
t
IRH
IR
t
IDS
INPUT DATA
2747 drw 06
t
IDH
t
IRL
Figure 2. Input Timing
SI
(7)
(2)
(4)
(1)
IR
(3)
(5)
(6)
INPUT DATA
STABLE DATA
2747 drw 07
NOTES:
1. IR HIGH indicates space is available and a SI pulse may be applied.
2. Input Data is loaded into the first word.
3. IR goes LOW indicating the first word is full.
4. The write pointer is incremented.
5. The FIFO is ready for the next word.
6. If the FIFO is full then the IR remains LOW.
7. SI pulses applied while IR is LOW will be ignored (see Figure 4).
Figure 3. The Mechanism of Shifting Data Into the FIFO
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