HD74BC245A
Octal Bus Transceivers With 3 State Outputs
ADE-205-008A (Z)
Rev. 1
March 1993
Description
The HD74BC245A 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 ten buffers with three state
outputs in a 20 pin package. Each device has an active low enable input
G and a direction control input
DiR. When DiR is high, data flows from the A inputs to the B outputs. When DiR is low, data flows from
the B inputs to the A outputs. When G is high, disables both A and B ports by placing then in a high
impedance.
Features
Input/Output are at high impedance state when power supply is off.
Built in input pull up circuit can make input pins be open, when not used.
TTL level input
Wide operating temperature range
Ta = 40 to + 85C
Function Table
Control Inputs
G
DiR
Operation
L
L
B data to A bus
L
H
A data to B bus
H
X
Z
H :
High level
L
:
Low level
Z
:
High impedance
HD74BC245A
2
Pin Arrangement
(Top view)
1
2
3
4
5
6
7
8
9
10
12
11
13
14
15
16
17
18
19
20
V
CC
GND
A1
A2
A3
A4
A5
A6
A7
A8
DiR
B1
B2
B3
B4
B5
B6
B7
B8
G
Absolute Maximum Ratings
Item
Symbol
Rating
Unit
Supply voltage
V
CC
0.5 to +7.0
V
Input diode current
I
IK
30
mA
Input voltage
V
IN
0.5 to +7.5
V
Output voltage
V
OUT
0.5 to +7.5
V
Off state output voltage
V
OUT(off)
0.5 to +5.5
V
Storage temperature
Tstg
65 to +150
C
Note:
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.
HD74BC245A
3
Recommended Operating Conditions
Item
Symbol
Min
Typ
Max
Unit
Supply voltage
V
CC
4.5
5.0
5.5
V
Input voltage
V
IN
0
--
V
CC
V
Output voltage
V
OUT
0
--
V
CC
V
Operating temperature
Topr
40
--
85
C
Input rise/fall time*
1
t
r
, t
f
0
--
8
ns/V
Note:
1. This item guarantees maximum limit when one input switches.
Waveform: Refer to test circuit of switching characteristics.
Logic Diagram
A2
A1
B1
B2
B3
B4
B5
B6
B7
B8
A8
A7
A6
A5
A4
A3
DiR
G
HD74BC245A
4
Electrical Characteristics (Ta = 40C to +85C)
Item
Symbol
V
CC
(V)
Min
Max
Unit
Test Conditions
Input voltage
V
IH
2.0
--
V
V
IL
--
0.8
V
Output voltage
V
OH
4.5
2.4
--
V
I
OH
= 3 mA
4.5
2.0
--
V
I
OH
= 15 mA
V
OL
4.5
--
0.5
V
I
OL
= 48 mA
4.5
--
0.55
V
I
OL
= 64 mA
Input diode voltage
V
IK
4.5
--
1.2
V
I
IN
= 18 mA
Input current
I
I
5.5
--
250
A
V
IN
= 0 V
5.5
--
100
A
An or Bn, V
IN
= 5.5 V
5.5
--
1.0
A
DiR or
G
, V
IN
= 5.5 V
5.5
--
100
A
DiR or
G
, V
IN
= 7.0 V
Short circuit output current*
1
I
OS
5.5
100
225
mA
V
O
= 0 V, V
IN
= 5.5 V
Off state output current
I
OZH
5.5
--
100
A
V
O
= 2.7 V
I
OZL
5.5
--
250
A
V
O
= 0.5 V
Supply current
I
CCL
5.5
--
31.5
mA
V
IN
= 0 or 5.5 V
All outputs is "L"
I
CCH
5.5
--
0.5
mA
V
IN
= 0 or 5.5 V
All outputs is "H"
I
CCZ
5.5
--
4.5
mA
V
IN
= 0 or 5.5 V
All outputs is "Z"
I
CCT
*
2
5.5
--
1.5
mA
V
IN
= 3.4 or 0.5 V
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.
HD74BC245A
5
Switching Test Method (C
L
= 50 pF)
Ta = 25
C
V
CC
= 5.0 V
Ta = 40 to 85
C
V
CC
= 5.0 V
10%
Item
Symbol
Min
Max
Min
Max
Unit
Test Conditions
Propagation delay time
t
PLH
3.0
6.0
3.0
7.0
ns
An to Bn
t
PHL
3.0
6.0
3.0
7.0
t
PLH
3.0
6.0
3.0
7.0
ns
Bn to An
t
PHL
3.0
6.0
3.0
7.0
Output enable time
t
ZH
3.0
9.0
3.0
11.0
ns
G
to Bn
t
ZL
3.0
9.0
3.0
11.0
t
ZH
3.0
9.0
3.0
11.0
ns
G
to An
t
ZL
3.0
9.0
3.0
11.0
Output disable time
t
HZ
3.0
8.0
3.0
10.0
ns
G
to Bn
t
LZ
3.0
8.0
3.0
10.0
t
HZ
3.0
8.0
3.0
10.0
ns
G
to An
t
LZ
3.0
8.0
3.0
10.0
Input capacitanse
C
IN
3.0(Typ)
--
pF
V
IN
= V
CC
or GND
Output capacitance
C
I/O
15.0(Typ)
--
pF
V
I/O
= V
CC
or GND
Test Circuit
V
CC
See Function Table
V
CC
A1
Output
OPEN
7V
C =
50 pF
L
G
DiR
B1
Pulse Generator
Z
out
= 50
Input
50 Scope
S1
*4
500
450
Notes:
1.
C
L
includes probe and jig capacitance.
2.
A2-B2, A3-B3, A4-B4, A5-B5, A6-B6, A7-B7, A8-B8 are identical to above load circuit.
3.
S1: Input-Output change switch.
4.
Open: t
PLH
, t
PHL
, t
ZH
, t
HZ
7 V: t
ZL
, t
LZ
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