Philips Semiconductors
Product specification
Octal bus transceiver/register (3-State)
74ABT646A
FEATURES
•
Combines 74ABT245 and 74ABT374 type functions in one device
•
Independent registers for A and B buses
•
Live insertion/extraction permitted
•
Power-up 3-State
•
Power-up reset
•
Multiplexed real-time and stored data
•
Output capability: +64mA/–32mA
•
Latch-up protection exceeds 500mA per Jedec Std 17
•
ESD protection exceeds 2000 V per MIL STD 883 Method 3015
and 200 V per Machine Model
The 74ABT646A transceiver/register consists 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 the internal registers. Data on the A or B bus will be clocked
into the registers as the appropriate clock pin goes High. Output
Enable (OE) and DIR pins are provided to control the transceiver
function. In the transceiver mode, data present at the high
impedance port may be stored in either the A or B register or both.
The Select (SAB, SBA) pins determine whether data is stored or
transferred through the device in real-time. The DIR determines
which bus will receive data when the OE is active (Low). In the
isolation mode (OE = High), data from Bus A may be stored in the B
register and/or data from Bus B may be stored in the A register.
When an output function is disabled, the input function is still
enabled and may be used to store and transmit data. Only one of
the two buses, A or B, may be driven at a time. The examples on the
next page demonstrate the four fundamental bus management
functions that can be performed with the 74ABT646A.
DESCRIPTION
The 74ABT646A high-performance BiCMOS device combines low
static and dynamic power dissipation with high speed and high
output drive.
QUICK REFERENCE DATA
SYMBOL
t
PLH
t
PHL
C
IN
C
I/O
I
CCZ
PARAMETER
Propagation delay
An to Bn or Bn to An
Input capacitance
CP, S, OE, DIR
I/O capacitance
Total supply current
CONDITIONS
T
amb
= 25°C; GND = 0V
C
L
= 50pF; V
CC
= 5V
V
I
= 0V or V
CC
Outputs disabled;
V
O
= 0V or V
CC
Outputs disabled; V
CC
=5.5V
TYPICAL
3.2
3.7
4
7
110
UNIT
ns
pF
pF
µA
ORDERING INFORMATION
PACKAGES
24-Pin Plastic DIP
24-Pin plastic SO
24-Pin Plastic SSOP Type II
24-Pin Plastic TSSOP Type I
TEMPERATURE RANGE
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
OUTSIDE NORTH AMERICA
74ABT646A N
74ABT646A D
74ABT646A DB
74ABT646A PW
NORTH AMERICA
74ABT646A N
74ABT646A D
74ABT646A DB
7ABT646APW DH
DWG NUMBER
SOT222-1
SOT137-1
SOT340-1
SOT355-1
PIN CONFIGURATION
CPAB
SAB
DIR
A0
A1
A2
A3
A4
A5
A6
A7
GND
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
V
CC
CPBA
SBA
OE
B0
B1
B2
B3
B4
B5
B6
B7
PIN DESCRIPTION
PIN NUMBER
1, 23
2, 22
3
4, 5, 6, 7,
8, 9, 10, 11
20, 19, 18, 17,
16, 15, 14, 13
21
12
24
SYMBOL
CPAB /
CPBA
SAB / SBA
DIR
A0 – A7
B0 – B7
OE
GND
V
CC
FUNCTION
A to B clock input / B to A clock
input
A to B select input / B to A
select input
Direction control input
Data inputs/outputs (A side)
Data inputs/outputs (B side)
Output enable input
(active-Low)
Ground (0V)
Positive supply voltage
SA00082
1998 Feb 17
2
853-1553 18978
Philips Semiconductors
Product specification
Octal bus transceiver/register (3-State)
74ABT646A
FUNCTION TABLE
INPUTS
OE
X
X
H
H
L
L
L
L
H
L
X
↑
*
=
=
=
=
DIR
X
X
X
X
L
L
CPAB
↑
X
↑
H or L
X
X
CPBA
X
↑
↑
H or L
X
H or L
SAB
X
X
X
X
X
X
SBA
X
X
X
X
L
H
An
Input
Unspecified
output*
Input
Output
DATA I/O
Bn
Unspecified
output*
Input
Input
Input
OPERATING MODE
Store A, B unspecified
Store B, A unspecified
Store A and B data
Isolation, hold storage
Real time B data to A bus
Stored B data to A bus
H
X
X
L
X
Real time A data to B bus
Input
Output
H
H or L
X
H
X
Stored A data to B bus
High voltage level
Low voltage level
Don’t care
Low-to-High clock transition
The data output function may be enabled or disabled by various signals at the OE input. Data input functions are always enabled, i.e.,
data at the bus pins will be stored on every Low-to-High transition of the clock.
LOGIC DIAGRAM
21
OE
3
DIR
23
CPBA
22
SBA
1
CPAB
2
SAB
1of 8 Channels
1D
C1
Q
A0
4
1D
C1
Q
20
B0
A1
A2
A3
A4
A5
A6
A7
5
6
7
8
9
10
11
DETAIL A X 7
19
18
17
16
15
14
13
B1
B2
B3
B4
B5
B6
B7
SA00086
1998 Feb 17
4
Philips Semiconductors
Product specification
Octal bus transceiver/register (3-State)
74ABT646A
ABSOLUTE MAXIMUM RATINGS
1, 2
SYMBOL
V
CC
I
IK
V
I
I
OK
V
OUT
I
OUT
T
stg
PARAMETER
DC supply voltage
DC input diode current
DC input voltage
3
DC output diode current
DC output voltage
3
DC output current
Storage temperature range
V
O
< 0
output in Off or High state
output in Low state
V
I
< 0
CONDITIONS
RATING
–0.5 to +7.0
–18
–1.2 to +7.0
–50
–0.5 to +5.5
128
–65 to 150
UNIT
V
mA
V
mA
V
mA
°C
NOTES:
1. Stresses beyond those listed 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.
2. The performance capability of a high-performance integrated circuit in conjunction with its thermal environment can create junction
temperatures which are detrimental to reliability. The maximum junction temperature of this integrated circuit should not exceed 150°C.
3. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
RECOMMENDED OPERATING CONDITIONS
LIMITS
SYMBOL
V
CC
V
I
V
IH
V
IL
I
OH
I
OL
∆t/∆v
T
amb
DC supply voltage
Input voltage
High-level input voltage
Low-level Input voltage
High-level output current
Low-level output current
Input transition rise or fall rate
Operating free-air temperature range
0
–40
PARAMETER
Min
4.5
0
2.0
0.8
–32
64
10
+85
Max
5.5
V
CC
V
V
V
V
mA
mA
ns/V
°C
UNIT
1998 Feb 17
5
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