8 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.

8.1 Application Information

The SN74LVC08A is used to drive CMOS device and used for implementing AND logic. The LVC family can

support current drive of about 24 mA at 3-V VCC. The inputs for SN74LVC08A are 5.5-V tolerant allowing it to

translate down to VCC.

8.2 Typical Application

A

B

Y

C

R

Figure 8-1. Three Input AND Gate Implementation and Driving LED

8.2.1 Design Requirements

This device uses CMOS technology and has balanced output drive. Take care to avoid bus contention because

it can drive currents that would exceed maximum limits. The high drive will also create fast edges into light loads

so routing and load conditions should be considered to prevent ringing.

8.2.2 Detailed Design Procedure

SN74LVC08A contains four AND gates in one package which can be used for individual AND function or to

implement complex Boolean logic. Figure 8-1 shows an example of implementing 3input AND function. AB are

inputs for AND gate which are connected to another AND gate. Z= A × B × C. SN74LVC08A support high drive

current of 24 mA which can be used to drive LEDs of even Drive low current signal FETs, an example is shown

in Figure 8-1 TI recommends to use a series resistance to limit the current. If VCC is 3 V, and LED current should

be 10 mA, and the forward-voltage of LED is 2.5 V, then R as shown in Figure 8-1 is calculated using Equation

1:

R = (VCC – VLED) / I

(1)

R = (3 – 2.5) / 0.01 = 50 Ω

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SN54LVC08A, SN74LVC08A

SCAS283U – JANUARY 1993 – REVISED MARCH 2024

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