Datasheet

1
2
4
6
8
19
11
13
15
17
3
5
7
9
12
14
16
18
1A1
1A2
1A3
1A4
1Y1
2A1
2A2
2A3
2A4
2Y1
1Y2
1Y3
1Y4
2Y2
2Y3
2Y4
2OE
1OE
Copyright © 2016, Texas Instruments Incorporated
9
SN54HCT244 , SN74HCT244
www.ti.com SCLS175E –MONTH 2003–REVISED AUGUST 2016
Product Folder Links: SN54HCT244 SN74HCT244
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8 Detailed Description
8.1 Overview
The SNx4HCT244 device is organized as two 4-bit buffers and line drivers with separate output-enable (OE)
inputs. When OE is low, the device passes data from the A inputs to the Y outputs. When OE is high, the outputs
are in the high-impedance state. To ensure the high-impedance state during power up or power down, OE must
be tied to V
CC
through a pullup resistor; the minimum value of the resistor is determined by the current-sinking
capability of the driver.
8.2 Functional Block Diagram
Figure 3. Logic Diagram (Positive Logic)
8.3 Feature Description
The SN74HCT244 device can drive up to 15 LSTTL loads. This device has low power consumption of 80-µA I
CC
.
The SN74HCT244 also has 3 state outputs that allow the outputs to go to high impedance, low or high.
8.4 Device Functional Modes
Table 1 lists the functions of the SNx4HC244.
Table 1. Function Table
INPUTS
OUTPUT
Y
OE A
L H H
L L L
H X Z