TI SN74HC646NT

SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
D
Independent Registers for A and B Buses
Multiplexed Real-Time and Stored Data
True Data Paths
High-Current 3-State Outputs Can Drive up
to 15 LSTTL Loads
Package Options Include Plastic
Small-Outline (DW) and Ceramic Flat (W)
Packages, Ceramic Chip Carriers (FK), and
Standard Plastic (NT) and Ceramic (JT)
300-mil DIPs
SN54HC646 . . . JT OR W PACKAGE
SN74HC646 . . . DW OR NT PACKAGE
(TOP VIEW)
CLKAB
SAB
DIR
A1
A2
A3
A4
A5
A6
A7
A8
GND
description
The ’HC646 consist of bus-transceiver circuits
with 3-state outputs, D-type flip-flops, and control
circuitry arranged for multiplexed transmission of
data directly from the input bus or from the internal
registers. Data on the A or B bus is clocked into the
registers on the low-to-high transition of the
appropriate clock (CLKAB or CLKBA) input.
Figure 1 illustrates the four fundamental busmanagement functions that can be performed
with the ’HC646.
The select-control (SAB and SBA) inputs can
multiplex stored and real-time (transparent mode)
data. DIR determines which bus receives data
when OE is active (low). In the isolation mode (OE
high), A data may be stored in one register and /or
B data may be stored in the other register.
24
2
23
3
22
4
21
5
20
6
19
7
18
8
17
9
16
10
15
11
14
12
13
VCC
CLKBA
SBA
OE
B1
B2
B3
B4
B5
B6
B7
B8
DIR
SAB
CLKAB
NC
VCC
CLKBA
SBA
SN54HC646 . . . FK PACKAGE
(TOP VIEW)
A1
A2
A3
NC
A4
A5
A6
5
2 1 28 27 26
25
6
24
7
23
8
22
9
21
10
20
4
11
3
19
12 13 14 15 16 17 18
A7
A8
GND
NC
B8
Output-enable (OE) and direction-control (DIR)
inputs control the transceiver functions. In the
transceiver mode, data present at the
high-impedance port may be stored in either or
both registers.
1
OE
B1
B2
NC
B3
B4
B5
B7
B6
D
D
D
D
NC – No internal connection
When an output function is disabled, the input function is still enabled and can be used to store and transmit
data. Only one of the two buses, A or B, may be driven at a time.
The SN54HC646 is characterized for operation over the full military temperature range of – 55°C to 125°C. The
SN74HC646 is characterized for operation from –40°C to 85°C.
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  1997, Texas Instruments Incorporated
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information 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
SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
21
OE
L
3
DIR
L
1
23
CLKAB CLKBA
X
X
2
SAB
X
BUS B
BUS A
BUS A
BUS B
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
22
SBA
L
21
OE
L
3
DIR
H
3
DIR
X
X
X
1
23
CLKAB CLKBA
X
↑
X
↑
↑
↑
2
SAB
X
X
X
22
SBA
X
X
X
21
OE
L
L
22
SBA
X
BUS B
3
DIR
L
H
STORAGE FROM
A, B, OR A AND B
1
CLKAB
X
H or L
23
CLKBA
H or L
X
2
SAB
X
H
TRANSFER STORED DATA
TO A AND/OR B
Pin numbers shown are for the DW, JT, NT, and W packages.
Figure 1. Bus-Management Functions
2
2
SAB
L
BUS A
BUS A
21
OE
X
X
H
23
CLKBA
X
REAL-TIME TRANSFER
BUS A TO BUS B
BUS B
REAL-TIME TRANSFER
BUS B TO BUS A
1
CLKAB
X
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22
SBA
H
X
SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
FUNCTION TABLE
INPUTS
DATA I/O
OPERATION OR FUNCTION
OE
DIR
CLKAB
CLKBA
SAB
SBA
A1– A8
B1– B8
X
X
↑
X
X
X
Input
Unspecified†
Input
Store A, B unspecified†
Store B, A unspecified†
X
X
X
↑
X
X
Unspecified†
H
X
↑
↑
X
X
Input
Input
Store A and B data
H
X
H or L
H or L
X
X
Input disabled
Input disabled
Isolation, hold storage
L
L
X
X
X
L
Output
Input
Real-time B data to A bus
L
L
X
H or L
X
H
Output
Input
Stored B data to A bus
L
H
X
X
L
X
Input
Output
Real-time A data to B bus
L
H
H or L
X
H
X
Input
Output
Stored A data to B bus
† The data-output functions can be enabled or disabled by various signals at OE and DIR. Data-input functions are always enabled; i.e., data at
the bus terminals is stored on every low-to-high transition of the clock inputs.
logic symbol‡
OE
DIR
CLKBA
SBA
CLKAB
SAB
A1
21
3
23
22
1
2
G3
3 EN1 [BA]
3 EN2 [AB]
C4
G5
C6
G7
≥1
4
1
7
1
A3
A4
A5
A6
A7
A8
20
B1
5 1
6D
A2
4D
5
≥1
2
7
5
19
6
18
7
17
8
16
9
15
10
14
11
13
B2
B3
B4
B5
B6
B7
B8
‡ This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the DW, JT, NT, and W packages.
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3
SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
logic diagram (positive logic)
OE
DIR
CLKBA
SBA
CLKAB
SAB
21
3
23
22
1
2
One of Eight Channels
1D
C1
A1
4
20
B1
1D
C1
To Seven Other Channels
Pin numbers shown are for the DW, JT, NT, and W packages.
absolute maximum ratings over operating free-air temperature range†
Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Input clamp current, IIK (VI < 0 or VI > VCC) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
Output clamp current, IOK (VO < 0 or VO > VCC) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
Continuous output current, IO (VO = 0 to VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±35 mA
Continuous current through VCC or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±70 mA
Package thermal impedance, θJA (see Note 2): DW package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81°C/W
NT package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67°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 voltage ratings may be exceeded if the input and output current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace
length of zero.
4
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SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
recommended operating conditions
SN54HC646
VCC
VIH
Supply voltage
VCC = 2 V
VCC = 4.5 V
High-level input voltage
VCC = 6 V
VCC = 2 V
VIL
VI
VO
Low-level input voltage
Input voltage
Output voltage
Input transition (rise and fall) time
TA
Operating free-air temperature
NOM
MAX
2
5
6
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
MIN
NOM
MAX
2
5
6
1.5
1.5
3.15
3.15
4.2
VCC = 4.5 V
VCC = 6 V
tt
SN74HC646
MIN
UNIT
V
V
4.2
0
0.5
0
0.5
0
1.35
0
1.35
0
1.8
0
1.8
0
0
0
VCC
VCC
0
VCC
VCC
0
1000
0
1000
0
500
0
500
0
400
0
400
–55
125
–40
85
V
V
V
ns
°C
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
VOH
TEST CONDITIONS
IOZ
ICC
Ci
A or B
SN54HC646
MIN
MAX
SN74HC646
MIN
MAX
UNIT
2V
1.9
1.998
1.9
1.9
4.4
4.499
4.4
4.4
6V
5.9
5.999
5.9
5.9
IOH = –6 mA
IOH = –7.8 mA
4.5 V
3.98
4.3
3.7
3.84
6V
5.48
5.8
5.2
5.34
2V
0.002
0.1
0.1
0.1
IOL = 20 µA
4.5 V
0.001
0.1
0.1
0.1
6V
0.001
0.1
0.1
0.1
4.5 V
0.17
0.26
0.4
0.33
6V
0.15
0.26
0.4
0.33
VI = VCC or 0
6V
±0.1
±100
±1000
±1000
nA
VO = VCC or 0
VI = VCC or 0,
6V
±0.01
±0.5
±10
±5
µA
8
160
80
µA
10
10
10
pF
IOL = 6 mA
IOL = 7.8 mA
II
TA = 25°C
TYP
MAX
4.5 V
VI = VIH or VIL
Control
inputs
MIN
IOH = –20 µA
VI = VIH or VIL
VOL
VCC
IO = 0
Control
inputs
6V
2 V to 6 V
3
V
V
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
POST OFFICE BOX 655303
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5
SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
timing requirements over recommended operating free-air temperature range (unless otherwise
noted)
VCC
fclock
tw
tsu
th
Clock frequency
Pulse duration, CLKBA or CLKAB high or low
Setup time, A before CLKAB↑
↑ or B before CLKBA↑
↑
Hold time, A after CLKAB↑
↑ or B after CLKBA↑
↑
TA = 25°C
MIN
MAX
POST OFFICE BOX 655303
SN74HC646
MIN
MAX
MIN
MAX
2V
0
6
0
4.3
0
5.5
4.5 V
0
31
0
22
0
27
6V
0
36
0
25
0
31
2V
80
115
95
4.5 V
16
23
19
6V
14
20
16
2V
100
150
125
4.5 V
20
30
25
6V
17
26
21
2V
5
5
5
4.5 V
5
5
5
6V
5
5
5
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
6
SN54HC646
• DALLAS, TEXAS 75265
UNIT
MHz
ns
ns
ns
SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
switching characteristics over recommended operating free-air temperature range, CL = 50 pF
(unless otherwise noted) (see Figure 2)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
fmax
CLKBA or CLKAB
tpd
A or B
SBA or SAB†
ten
tdis
ten
tdis
OE
OE
DIR
DIR
tt
A or B
B or A
A or B
A or B
A or B
A or B
A or B
Any
VCC
MIN
TA = 25°C
TYP
MAX
SN54HC646
MIN
MAX
SN74HC646
MIN
2V
6
11
4.4
5.5
4.5 V
31
54
22
27
6V
36
64
25
31
MAX
UNIT
MHz
2V
65
180
270
225
4.5 V
18
36
54
45
6V
14
31
46
38
2V
50
135
205
170
4.5 V
14
27
41
34
6V
11
23
35
29
2V
70
190
285
240
4.5 V
20
38
57
48
6V
16
32
48
41
2V
85
245
370
305
4.5 V
25
49
74
61
6V
20
42
63
52
2V
85
245
370
305
4.5 V
25
49
74
61
6V
20
42
63
52
2V
80
245
370
305
4.5 V
25
49
74
61
6V
20
42
63
52
2V
80
245
370
305
4.5 V
25
49
74
61
6V
20
42
63
52
2V
28
60
90
75
4.5 V
8
12
18
15
6V
6
10
15
13
ns
ns
ns
ns
ns
ns
† These parameters are measured with the internal output state of the storage register opposite that of the bus input.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
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SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
switching characteristics over recommended operating free-air temperature range, CL = 150 pF
(unless otherwise noted) (see Figure 2)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
CLKBA or CLKAB
tpd
A or B
A or B
B or A
SBA or SAB†
A or B
OE
A or B
ten
DIR
A or B
tt
Any
VCC
MIN
TA = 25°C
TYP
MAX
SN54HC646
MIN
MAX
SN74HC646
MIN
MAX
2V
90
265
400
330
4.5 V
24
53
80
66
6V
20
46
68
57
2V
70
220
335
280
4.5 V
20
44
67
56
6V
15
38
57
49
2V
80
275
415
345
4.5 V
24
55
83
69
6V
20
47
70
60
2V
113
330
500
410
4.5 V
33
66
100
82
6V
27
57
85
71
2V
113
330
500
410
4.5 V
33
66
100
82
6V
27
57
85
71
2V
45
210
315
265
4.5 V
17
42
63
53
6V
13
36
53
† These parameters are measured with the internal output state of the storage register opposite that of the bus input.
UNIT
ns
ns
ns
43
operating characteristics, TA = 25°C
PARAMETER
Cpd
TEST CONDITIONS
Power dissipation capacitance
No load
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
8
POST OFFICE BOX 655303
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TYP
50
UNIT
pF
SN54HC646, SN74HC646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS150B – DECEMBER 1982 – REVISED MAY 1997
PARAMETER MEASUREMENT INFORMATION
VCC
From Output
Under Test
CL
(see Note A)
PARAMETER
S1
Test
Point
tPZH
ten
RL
1 kΩ
tPZL
tPHZ
tdis
S2
RL
1 kΩ
Data
Input
VCC
50%
10%
50%
50%
0V
In-Phase
Output
50%
10%
tPHL
90%
90%
tr
tPHL
Out-ofPhase
Output
90%
tf
Closed
Closed
Open
Open
Open
VCC
th
90%
90%
VCC
50%
10% 0 V
tf
50%
10%
Output
Control
(Low-Level
Enabling)
VCC
50%
50%
0V
tPZL
VOH
50%
10% V
OL
tf
Output
Waveform 1
(See Note B)
tPLZ
≈ VCC
≈ VCC
50%
10%
VOL
tPZH
tPLH
50%
10%
Open
VOLTAGE WAVEFORMS
SETUP AND HOLD AND INPUT RISE AND FALL TIMES
VCC
tPLH
Open
tr
VOLTAGE WAVEFORMS
PULSE DURATIONS
50%
Closed
0V
0V
Input
Closed
tsu
0V
50%
Open
50%
50%
tw
Low-Level
Pulse
50 pF
or
150 pF
50 pF
or
150 pF
––
Reference
Input
VCC
S2
50 pF
LOAD CIRCUIT
50%
S1
tPLZ
tpd or tt
High-Level
Pulse
CL
90%
VOH
VOL
Output
Waveform 2
(See Note B)
tr
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT TRANSITION TIMES
50%
90%
VOH
≈0V
tPHZ
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES FOR 3-STATE OUTPUTS
NOTES: A. CL includes probe and test-fixture capacitance.
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators having the following
characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr = 6 ns, tf = 6 ns.
D. For clock inputs, fmax is measured when the input duty cycle is 50%.
E. The outputs are measured one at a time with one input transition per measurement.
F. tPLZ and tPHZ are the same as tdis.
G. tPZL and tPZH are the same as ten.
H. tPLH and tPHL are the same as tpd.
Figure 2. Load Circuit and Voltage Waveforms
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9
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any product or service without notice, and advise customers to obtain the latest version of relevant information
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pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
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.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
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Copyright  1998, Texas Instruments Incorporated