OC

PG

ON/OFF

RESET

Power Sup ply

Motor Con trol ler

On/Off Switch

Over

Temp

Detection

Over Current

Detection

OT

9

CD74HC08-Q1

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SCLS512B – JULY 2003 – REVISED APRIL 2020

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9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

In this application, three 2-input AND gates are combined to produce a 4-input AND gate function as shown in

Figure 7. The fourth gate can be used for another application in the system, or the inputs can be grounded and

the channel left unused.

The CD74HC08-Q1 is used to directly control the RESET pin of a motor controller. The controller requires four

input signals to all be HIGH before being enabled, and should be disabled in the event that any one signal goes

LOW. The 4-input AND gate function combines the four individual reset signals into a single active-low reset

signal.

9.2 Typical Application

Figure 7. Typical application block diagram

9.2.1 Design Requirements

9.2.1.1 Power Considerations

Ensure the desired supply voltage is within the range specified in the Recommended Operating Conditions. The

supply voltage sets the device's electrical characteristics as described in the Electrical Characteristics.

The supply must be capable of sourcing current equal to the total current to be sourced by all outputs of the

CD74HC08-Q1 plus the maximum supply current, ICC, listed in the Electrical Characteristics. The logic device

can only source or sink as much current as it is provided at the supply and ground pins, respectively. Be sure not

to exceed the maximum total current through GND or VCC listed in the Absolute Maximum Ratings.

Total power consumption can be calculated using the information provided in CMOS Power Consumption and

Cpd Calculation.

Thermal increase can be calculated using the information provided in Thermal Characteristics of Standard Linear

and Logic (SLL) Packages and Devices.