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TOSHIBA
TOSHIBA CORPORATION
1/3
TC74AC520
TC74AC521
TC74AC Series
The information contained here is subject to change without notice.
The information contained herein is presented only as guide for the applications of our products. No responsibility is assumed by TOSHIBA for any infringements of patents or other rights of the third parties
which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of TOSHIBA or others. These TOSHIBA products are intended for usage in general electronic
equipments (office equipment, communication equipment, measuring equipment, domestic electrification, etc.) Please make sure that you consult with us before you use these TOSHIBA products in equip-
ments which require high quality and/or reliability, and in equipments which could have major impact to the welfare of human life (atomic energy control, spaceship, traffic signal, combustion control, all types
of safety devices, etc.). TOSHIBA cannot accept liability to any damage which may occur in case these TOSHIBA products were used in the mentioned equipments without prior consultation with TOSHIBA.
520: with Pull-up Resistor
Features:
High Speed:
t
pd
= 6.4ns (typ.) at V
CC
= 5V
Low Power Dissipation:
I
CC
= 8
μ
A (max.) at T
a
=
25
°
C*
High Noise Immunity:
V
NIH
= V
NIL
= 28% V
CC
(min.)
Symmetrical Output Impedance:
S
I
OH
S
= I
OL
= 24mA
(min.). Capability of driving 50
transmission lines.
Balanced Propagation Delays:
t
pLH
= t
pHL
Wide Operating Voltage Range:
V
CC
(opr) = 2V~5.5V
Pin and Function Compatible with 74F521
Available in DIP, SOIC and SOP Packages
* for AC521 only
Pin Assignment
Truth Table
X:
Don’t Care
The TC74AC520 and TC74AC521 are advanced high speed
CMOS 8-BIT DIGITAL COMPARATORS fabricated with sili-
con gate and double-layer metal wiring C
2
MOS technology.
They achieve the high speed operation similar to equivalent
Bipolar Schottky TTL, while maintaining the CMOS low
power dissipation.
They compare two 8-bit binary or BCD words applied
inputs P0~P7, and inputs Q0~Q7, and indicate whether or
not they are equal.
The TC74AC520 is equipped with pull-up resistors (20
typ.) to inputs Q0~Q7 and features pull-up resistors on the Q
inputs for switch data.
A signal active low enable is provided to facilitate cascad-
ing of several packages to compare words greater than 8
bits.
All inputs are equipped with protection circuits against
static discharge or transient excess voltage.
IEC Logic Symbol
INPUTS
OUTPUT
P, Q
G
P = Q
P = Q
P
≠
Q
X
L
L
L
H
H
H
1
2
3
4
5
6
7
20
19
18
17
16
15
14
V
CC
P=Q
Q7
P7
Q6
P6
Q5
G
P0
Q0
P1
Q1
P2
Q2
13
P5
8
P3
9
12
Q4
Q3
11
P4
10
GND
(TOP VIEW)
COMP
(1)
G
(2)
P0
(4)
P1
(6)
P2
(8)
P3
(11)
P4
(13)
P5
(15)
(17)
P6
P7
0
7
P
(3)
Q0
(5)
Q1
(7)
Q2
(9)
Q3
(12)
Q4
(14)
Q5
(16)
Q6
(18)
Q7
0
7
Q
P=Q
(19)
P=Q
EN