8 Detailed Description

8.1 Overview

This device contains four independent 2-input AND Gates with Schmitt-trigger inputs. Each gate performs the

Boolean function Y = A ● B in positive logic.

8.2 Functional Block Diagram

One of Four Channels

xA

xB

xY

8.3 Feature Description

8.3.1 Balanced CMOS Push-Pull Outputs

This device includes balanced CMOS push-pull outputs. The term "balanced" indicates that the device can sink

and source similar currents. The drive capability of this device may create fast edges into light loads so routing

and load conditions should be considered to prevent ringing. Additionally, the outputs of this device are capable

of driving larger currents than the device can sustain without being damaged. It is important for the output power

of the device to be limited to avoid damage due to overcurrent. The electrical and thermal limits defined in the

Absolute Maximum Ratings must be followed at all times.

Unused push-pull CMOS outputs should be left disconnected.

8.3.2 CMOS Schmitt-Trigger Inputs

This device includes inputs with the Schmitt-trigger architecture. These inputs are high impedance and are

typically modeled as a resistor in parallel with the input capacitance given in the Electrical Characteristics table

from the input to ground. The worst case resistance is calculated with the maximum input voltage, given in the

Absolute Maximum Ratings table, and the maximum input leakage current, given in the Electrical Characteristics

table, using Ohm's law (R = V ÷ I).

table, which makes this device extremely tolerant to slow or noisy inputs. While the inputs can be driven much

slower than standard CMOS inputs, it is still recommended to properly terminate unused inputs. Driving the

inputs with slow transitioning signals will increase dynamic current consumption of the device. For additional

information regarding Schmitt-trigger inputs, please see Understanding Schmitt Triggers.

8.3.3 Clamp Diode Structure

The inputs and outputs to this device have both positive and negative clamping diodes as depicted in Electrical

Placement of Clamping Diodes for Each Input and Output.

CAUTION

Voltages beyond the values specified in the Absolute Maximum Ratings table can cause damage

to the device. The input and output voltage ratings may be exceeded if the input and output clamp-

current ratings are observed.

SN74HCS08-Q1

SCLS756D – MAY 2019 – REVISED MARCH 2021

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