HIT HD74BC240A Datasheet
HD74BC240A
Octal Buffers/Line Drivers With 3 State Outputs
ADE-205-006A(Z)
2nd Edition
March 1993
Description
The HD74BC240A 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 inverter drivers with
three state outputs in a 20 pin package. This device is a non inverting buffer and has two active low
enables (1G and 2G). Each enable independently controls 4 buffers.
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 + 85°C
Function Table
Inputs
G A Output Y
HX Z
LH L
LL H
H : High level
L : Low level
X : Immaterial
Z : High impedance
HD74BC240A
Pin Arrangement
1G
V
1
20
CC
1A1
2Y4
1A2
2Y3
1A3
2Y2
1A4
2Y1
GND
2
3
4
5
6
7
8
9
10
19
18
17
16
15
14
13
12
11
2G
1Y1
2A4
1Y2
2A3
1Y3
2A2
1Y4
2A1
(Top view)
Absolute Maximum Ratings
Item Symbol Rating Unit
Supply voltage V
Input diode current I
Input voltage V
Output voltage V
Off state output voltage V
CC
IK
IN
OUT
OUT(off)
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.
–0.5 to +7.0 V
±30 mA
–0.5 to +7.5 V
–0.5 to +7.5 V
–0.5 to +5.5 V
2
HD74BC240A
Recommended Operating Conditions
Item Symbol Min Typ Max Unit
Supply voltage V
Input voltage V
Output voltage V
CC
IN
OUT
Operating temperature Topr –40 — 85 °C
Input rise/fall time*
1
tr, t
f
Note: 1. This item guarantees maximum limit when one input switches.
Waveform: Refer to test circuit of switching characteristics.
Logic Diagram
1G
4.5 5.0 5.5 V
0—VCCV
0—VCCV
0 — 8 ns/V
2G
1A1
2Y4
1A2
2Y3
1A3
2Y2
1A4
2Y1
1Y1
2A4
1Y2
2A3
1Y3
2A2
1Y4
2A1
3
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