HD74BC620A
Octal Bus Transceivers With 3 State Outputs
ADE-205-024 (Z)
1st. Edition
Feb. 1994
Description
The HD74BC620A provides high drivability and operation equal to or better than high speed bipolar
standard logic IC by using Bi-CMOS process. The device features low power dissipation that is about 1/5
of high speed bipolar logic IC. When the frequency is 10 MHz. The device has eight bus transceivers with
three state outputs in a 20 pin package. This device allows data transmission from the A bus to the B bus or
from the B bus to the A bus depending upon the logic levels at the enable inputs (GBA and GAB). The
enable inputs can be used to disable the device so that the buses are effectively isolated.
Features
•
Input/Output are at high impedance state when power supply is off.
•
Input pins can be open, when not used, owing to built in input pull up circuit.
•
Input is TTL level.
•
Wide operating temperature range
Ta = –40 to +85°C.
Function Table
Enable Inputs
GBA
L
H
H
L
GAB
L
H
L
H
Operation
B
data to A bus
A
data to B bus
Isolation
B
data to A bus
A
data to B bus
H :
L :
High level
Low level
HD74BC620A
Pin Arrangement
GAB
A1
A2
A3
A4
A5
A6
A7
A8
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
CC
GBA
B1
B2
B3
B4
B5
B6
B7
B8
(Top view)
Absolute Maximum Ratings
Item
Supply voltage
Input diode current
Input voltage
Output voltage
Off state output voltage
Storage temperature
Note:
Symbol
V
CC
I
IK
V
IN
V
OUT
V
OUT(off)
Tstg
Rating
–0.5 to +7.0
±30
–0.5 to +7.5
–0.5 to +7.5
–0.5 to +5.5
–65 to +150
Unit
V
mA
V
V
V
°C
1. The absolute maximum ratings are values which must not individually be exceeded, and
furthermore, no two of which may be realized at the same time.
2
HD74BC620A
Recommended Operating Conditions
Item
Supply voltage
Input voltage
Ouput voltage
Operating temperature
Input rise/fall time*
1
Note:
Symbol
V
CC
V
IN
V
OUT
Topr
t
r
, t
f
Min
4.5
0
0
–40
0
Typ
5.0
—
—
—
—
Max
5.5
V
CC
V
CC
85
8
Unit
V
V
V
°C
ns/V
1. This item guarantees maximum limit when one input switches.
Waveform: Refer to test circuit of switching characteristics.
Logic Diagram
GBA
GAB
A1
B1
A2
B2
A3
B3
A8
B8
3
HD74BC620A
Electrical Characteristics
(Ta = –40 to +85°C)
Item
Input voltage
Symbol
V
IH
V
IL
Output voltage
V
OH
4.5
4.5
V
OL
4.5
4.5
Input diode voltage
Input current
V
IK
I
I
4.5
5.5
5.5
5.5
5.5
Output short circuit current*
1
Off state output current
I
OS
I
OZH
I
OZL
Supply current
I
CCL
I
CCH
I
CCZ
I
CCT
*
2
5.5
5.5
5.5
5.5
5.5
5.5
5.5
V
CC
(V)
Min
2.0
—
2.4
2.0
—
—
—
—
—
—
—
–100
—
—
—
—
—
—
Max
—
0.8
—
—
0.5
0.55
–1.2
–250
1.0
100
100
–225
–100
–250
29.5
2.5
4.5
1.5
Unit
V
V
V
V
V
V
V
µA
µA
µA
µA
mA
µA
µA
mA
mA
mA
mA
I
OH
= –3 mA
I
OH
= –15 mA
I
OL
= 48 mA
I
OL
= 64 mA
I
IN
= –18 mA
V
IN
= 0 V
GAB or
GBA,
V
IN
= 5.5 V
An or Bn, V
IN
= 5.5 V
GAB or
GBA
= 7 V
V
IN
= 0 or 5.5 V
V
O
= 2.7 V
V
O
= 0.5 V
V
IN
= 0 or 5.5 V
All outputs is “L”
V
IN
= 0 or 5.5 V
All outputs is “H”
V
IN
= 0 or 5.5 V
All outputs is “Z”
V
IN
= 3.4 or 0.5 V
Test Conditions
Notes: 1. Not more than one output should be shorted at a time and duration of the short circuit should not
exceed one second.
2. When input by the TTL level, it shows I
CC
increase at per one input pin.
4
HD74BC620A
Switching Characteristics
(C
L
= 50 pF)
Ta = 25°C
V
CC
= 5.0 V
Item
Propagation delay time
Symbol
t
PLH
t
PHL
t
PLH
t
PHL
Output enable time
t
ZH
t
ZL
t
ZH
t
ZL
Output disable time
t
HZ
t
LZ
t
HZ
t
LZ
Input capacitance
Output capacitance
C
IN
C
I/O
Min
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0 (Typ)
15.0 (Typ)
Max
6.0
6.0
6.0
6.0
9.0
9.0
9.0
9.0
8.0
8.0
8.0
8.0
Ta = –40 to +85°C
V
CC
= 5.0 V
±10%
Min
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
—
—
Max
7.0
7.0
7.0
7.0
11.0
11.0
11.0
11.0
10.0
10.0
10.0
10.0
pF
pF
V
IN
= V
CC
or GND
V
I/O
= V
CC
or GND
ns
GBA
to An
ns
GAB to Bn
ns
GBA
to An
ns
GAB to Bn
ns
Bn to An
Unit
ns
Test Conditions
An to Bn
5
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