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, as well as validating and testing their design

implementation to confirm system functionality.

9.1 Application Information

In this application, one 2-input open-drain NAND gate is used as shown in Figure 9-1. The other three gates can

be used for other applications in the system, or the inputs can be grounded and the channels left unused.

This device is used to directly control an LED. The LED is on when the inputs are both high, and off any other

time.

9.2 Typical Application

Power

Good 1

R

1

Power

Good 2

V

CC

Figure 9-1. Typical application schematic

9.2.1 Design Requirements

9.2.1.1 Power Considerations

Ensure the desired supply voltage is within the range specified in the Section 6.2. The supply voltage sets the

device's electrical characteristics as described in the Section 6.4.

The ground must be capable of sinking current equal to the total current to be sunk by all outputs of the

CD74HCT03 plus the maximum supply current, ICC, listed in Section 6.4. The logic device can only sink as

much current as is provided by the external pull-up resistor or other supply source. Be sure not to exceed the

maximum total current through GND listed in the Section 6.1.

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.

CAUTION

The maximum junction temperature, TJ(max) listed in the Section 6.1, is an additional limitation to

prevent damage to the device. Do not violate any values listed in the Section 6.1. These limits are

provided to prevent damage to the device.

9.2.1.2 Input Considerations

Unused inputs must be terminated to either VCC or ground. These can be directly terminated if the input is

completely unused, or they can be connected with a pull-up or pull-down resistor if the input is to be used

sometimes, but not always. A pull-up resistor is used for a default state of HIGH, and a pull-down resistor is used

CD74HCT03, CD54HCT03

SCHS414 – JUNE 2020

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