• Significant Power Reduction Compared to LSTTL
Logic ICs
• HC Types
- 2V to 6V Operation
- High Noise Immunity: N
at VCC = 5V
• HCT Types
- 4.5V to 5.5V Operation
- Direct LSTTL Input Logic Compatibility,
V
= 0.8V (Max), VIH = 2V (Min)
IL
- CMOS Input Compatibility, I
= 30%, NIH = 30% of V
IL
≤ 1µA at VOL, V
l
o
Applications
• Bit-Rate Smoothing
• CPU/Terminal Buffering
• Data Communications
• Peripheral Buffering
• Line Printer Input Buffers
• Auto-Dialers
• CRT Buffer Memories
• Radar Data Acquisition
C to 125oC
CC
OH
CD74HCT40105
High Speed CMOS Logic
4-Bit x 16-Word FIFO Register
Description
The Harris CD74HC40105 and CD74HCT40105 are highspeed silicon-gate CMOS devices that are compatible,
except for “shift-out” circuitry, with the Harris CD40105B.
They are low-power first-in-out (FIFO) “elastic” storage
registers that can store 16 four-bit words. The 40105 is
capable ofhandling input and outputdata at different shifting
rates. This feature makes particularly useful as a buffer
between asynchronous systems.
Each work position in the register is clocked by a control flipflop, which stores a marker bit. A “1” signifies that the position’s data is filled and a “0” denotes a vacancy in that position. The control flip-flop detects the state of the preceding
flip-flop and communicates its own status to the succeeding
flip-flop. When a control flip-flop is in the “0” state and sees a
“1” in the preceeding flip-flop, it generates a clock pulse that
transfers data from the preceding four data latches into its
own four data latches and resets the preceding flip-flop to
“0”. The first and last control flip-flops have buffered outputs.
Since all empty locations “bubble” automatically to the input
end, and all valid data ripple through to the output end, the
status of the first control flip-flop (DATA-IN READY) indicates
if the FIFO is full, and the status of the last flip-flop (DATAOUT READY) indicates if the FIFO contains data. As the
earliest data are removed from the bottom of the data stack
(the output end), all data entered later will automatically
propagate (ripple) toward the output.
Ordering Information
TEMP. RANGE
PART NUMBER
CD74HC40105E-55 to 12516 Ld PDIPE16.3
CD74HCT40105E-55 to 12516 Ld PDIPE16.3
CD74HC40105M-55 to 12516 Ld SOICM16.15
CD74HCT40105M-55 to 12516 Ld SOICM16.15
NOTES:
1. When ordering,use the entire partnumber. Add the suffix 96 to
obtain the variant in the tape and reel.
2. Wafer and die for this part number is available which meets all
electrical specifications. Please contact your local sales office or
Harris customer service for ordering information.
(oC)PACKAGEPKG. NO.
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright
Data can be entered whenever the DATA-IN READY (DIR)
flag is high, by a low to high transition on the SHIFT-IN (SI)
input. This input must go low momentarily before the next
word is accepted by the FIFO. The DIR flag will go low
momentarily, until the data have been transferred to the second location. The flag will remain low when all 16-word locations are filled with valid data, and further pulses on the SI
input will be ignored until DIR goes high.
Unloading Data
As soon as the first word has rippled to the output, the dataout ready output (DOR) goes HIGH and data of the first word
is available on the outputs. Data of other words can be
removed by a negative-going transition on the shift-out input
(
SO). This negative-going transition causes the DOR signal
to go LOW while the next word moves to the output. As long
as valid data is available in the FIFO, the DOR signal will go
high again, signifying that the next word is ready at the
output. When the FIFO is empty, DOR will remain LOW, and
any further commands will be ignored until a “1” marker
ripples down to the last control register and DOR goes
HIGH. If during unloading SI is HIGH, (FIFO is full) data on
the data input of the FIFO is entered in the first location.
V
16
CC
15
SO
14
DOR
13
Q0
12
Q1
Q2
11
10
Q3
MR
9
Three-State Outputs
In order to facilitate data busing, three-state outputs (Q0 to
Q3) are provided on the data output lines, while the load
condition of the register can be detected by the state of the
DOR output. A HIGH on the three-state control flag (output
enable input OE) forces the outputs into the high-impedance
OFF-state mode. Note that the shift-out signal, unlike that in
the Harris CD40105B, is independent of the three-state
output control. In the CD40105B, the three-state control
must not be shifted from High to Low when the shift-out
signal is Low (data loss would occur). In the high-speed
CMOS version this restriction has been eliminated.
Cascading
The 40105 can be cascaded to form longer registers simply
by connecting the DIR to SO and DOR to SI. In the cascaded
mode, a MASTER RESET pulse must be applied after the
supply voltage is turnedon. For words wider than four bits, the
DIR and the DOR outputs must be gated together with AND
gates. Theri outputs drive the SI and SO inputs in parallel, if
expanding is done in both directions (see Figures 12 and 13).
Functional Diagram
THREE-
STATE
CONTROL
D0
D1
D2
D3
SHIFT IN
SHIFT OUT
MASTER
RESET
4
5
6
7
3
15
1
9
GND = 8
V
= 16
CC
13
Q0
12
Q1
11
Q2
10
Q3
14
DATA-OUT
READY
2
DATA-IN
READY
Master Reset
A high on the MASTER RESET (MR) sets all the control
logic marker bits to “0”. DOR goes low and DIR goes high.
The contents of the data register are not changed, only
declared invalid, and will be superseded when the first word
is loaded. Thus, MR does not clear data within the register
but only the control logic. If the shift-in flag (SI) is HIGH
during the master reset pulse, data present at the input (D0
to D3) are immediately moved into the first location upon
completion of the reset process.
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
3. θJA is measured with the component mounted on an evaluation PC board in free air.
NOTE: Outputs should be switching from 10% VCC to 90% VCC in
accordance with device truth table. For f
, input duty cycle = 50%.
MAX
FIGURE 3. HC CLOCK PULSE RISE AND FALL TIMES AND
PULSE WIDTH
tr = 6nstf = 6ns
V
t
CC
GND
TLH
INPUT
t
INVERTING
OUTPUT
THL
t
PHL
90%
50%
10%
t
PLH
90%
50%
10%
FIGURE 5. HC TRANSITION TIMES AND PROPAGATION
DELAY TIMES, COMBINATION LOGIC
NOTE: Outputs should be switching from 10% VCC to 90% VCC in
accordance with device truth table. For f
, input duty cycle = 50%.
MAX
FIGURE 4. HCT CLOCK PULSE RISE AND FALL TIMES AND
PULSE WIDTH
= 6ns
t
PLH
t
f
1.3V
10%
90%
t
3V
GND
TLH
tr = 6ns
INPUT
t
INVERTING
OUTPUT
THL
t
PHL
2.7V
1.3V
0.3V
FIGURE 6. HCT TRANSITION TIMES AND PROPAGATION
DELAY TIMES, COMBINATION LOGIC
10
CD74HC40105, CD74HCT40105
Test Circuits and Waveforms
90%
t
PLH
IC
t
TLH
tfC
L
50%
C
50pF
CLOCK
INPUT
DAT A
INPUT
t
SU(H)
OUTPUT
t
REM
V
CC
SET, RESET
OR PRESET
trC
L
90%
10%
t
H(H)
50%
(Continued)
t
H(L)
t
SU(L)
t
THL
90%
50%
10%
t
PHL
L
V
CC
GND
V
CC
50%
GND
GND
CLOCK
INPUT
DAT A
INPUT
t
SU(H)
OUTPUT
t
REM
3V
SET, RESET
OR PRESET
trC
L
2.7V
0.3V
t
H(H)
tfC
L
3V
1.3V
GND
t
H(L)
3V
t
SU(L)
90%
1.3V
10%
t
1.3V
t
PHL
GND
THL
1.3V
90%
1.3V
t
1.3V
t
PLH
TLH
1.3V
GND
IC
C
L
50pF
FIGURE 7. HC SETUP TIMES, HOLD TIMES, REMOVAL TIME,
AND PROPAGATION DELAY TIMES FOR EDGE
TRIGGERED SEQUENTIAL LOGIC CIRCUITS
6ns6ns
OUTPUT
DISABLE
OUTPUT LOW
TO OFF
OUTPUT HIGH
TO OFF
50%
t
t
OUTPUTS
ENABLED
PLZ
PHZ
10%
90%
90%
10%
t
PZL
t
PZH
OUTPUTS
DISABLED
50%
50%
OUTPUTS
ENABLED
FIGURE 9. HC THREE-STATE PROPAGATION DELAY
WAVEFORM
OTHER
INPUTS
TIED HIGH
OR LOW
OUTPUT
DISABLE
IC WITH
THREE-
STATE
OUTPUT
V
CC
GND
OUTPUT
R
FIGURE 8. HCT SETUP TIMES, HOLD TIMES, REMOVAL TIME,
AND PROPAGATION DELAY TIMES FOR EDGE
TRIGGERED SEQUENTIAL LOGIC CIRCUITS
0.3
t
t
PZL
PZH
6ns
1.3V
t
r
OUTPUT
DISABLE
OUTPUT LOW
TO OFF
OUTPUT HIGH
TO OFF
t
t
OUTPUTS
ENABLED
6nst
PLZ
PHZ
10%
90%
f
2.7
1.3
OUTPUTS
DISABLED
FIGURE 10. HCT THREE-STATE PROPAGATION DELAY
WAVEFORM
= 1kΩ
L
C
L
50pF
VCC FOR t
GND FOR t
PLZ
PHZ
AND t
AND t
PZL
PZH
3V
GND
1.3V
OUTPUTS
ENABLED
NOTE: Open drain waveforms t
VCC, CL = 50pF.
FIGURE 11. HC AND HCT THREE-STATE PROPAGATION DELAY TEST CIRCUIT
PLZ
and t
are the same as those for three-state shown on the left. The test circuit is Output RL=1kΩto
PZL
11
SHIFT IN
DATA OUT
READY
SI DOR
D0
D1
D2
D3
MR
DIR
8-BIT
DAT A
SI DOR
D0
D1
D2
D3
MR
DIR
DATA IN READY
MASTER RESET
(NOTE)
NOTE: Pulse must be applied for cascading by 16 N bits.
FIGURE 13. EXPANSION, 8-BITS WIDE BY 16 N-BITS LONG USING HC/HCT40105
SO
SO
Q0
Q1
Q2
Q3
Q0
Q1
Q2
Q3
SI DOR
D0
D1
D2
D3
MR
DIR
SI DOR
D0
D1
D2
D3
MR
DIR
Q0
Q1
Q2
Q3
SO
8-BIT
DAT A
Q0
Q1
Q2
Q3
SO
SHIFT OUT
12
MASTER
RESET
SHIFT IN
INPUTS
OUTPUTS
INPUTS
(DATA VALID)
≈180ns
(NOTE 7)
SHIFT OUT
SHIFT-OUT PULSES
HAVE NO EFFECT
INPUT READY
(CLEAR OUT)
(NOTE 6)
OUTPUT READY
(DATA VALID)
DATA IN
(Db)
THREE-STATE
(OUTPUT
ENABLE)
DATA OUT(UNKNOWN)HIGH Z
(NOTE 6)
1011 100011111000
SHIFT-IN PULSES
HAVE NO EFFECT
≈180ns
(NOTE 8)
101110
INVALID
NOTES:
6. Data valid goes to high level in advance of the data out by a maximum of 38ns at VCC = 4.5V for CL = 50pF and TA = 25oC.
7. At VCC = 4.5V, ripple time from position 1 to position 16.
8. At VCC = 4.5V, ripple time from position 16 to position 1.
FIGURE 14. TIMING DIAGRAM FOR THE CD74HC/HCT40105
13
IMPORTANT NOTICE
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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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DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
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In order to minimize risks associated with the customer’s applications, adequate design and operating
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Copyright 1999, Texas Instruments Incorporated
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