7 Detailed Description

7.1 Overview

The maximum sink and source current is 24 mA.

Inputs can be driven from 1.8-V, 2.5-V, 3.3-V (LVTTL), or 5-V (CMOS) devices. This feature allows the use of this

device as translators in a mixed-system environment.

7.2 Functional Block Diagram

A

B

Y

Figure 7-1. Logic Diagram, Each Gate (Positive Logic)

7.3 Feature Description

7.3.1 Balanced High-Drive CMOS Push-Pull Outputs

A balanced output allows the device to sink and source similar currents. The high drive capability of this device

creates 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 power output of the device to be limited to avoid thermal runaway and

damage due to over-current. The electrical and thermal limits defined the in the Section 5.1 must be followed at

all times.

7.3.2 Standard CMOS Inputs

Standard CMOS inputs are high impedance and are typically modelled as a resistor in parallel with the input

capacitance given in the Section 5.6 and Section 5.7. The worst case resistance is calculated with the maximum

input voltage, given in the Section 5.1, and the maximum input leakage current, given in the Section 5.6 and

Section 5.7, using ohm's law (R = V ÷ I).

Signals applied to the inputs need to have fast edge rates, as defined by Δt/Δv in Section 5.3 and Section

5.4 to avoid excessive currents and oscillations. If a slow or noisy input signal is required, a device with a

Schmitt-trigger input should be utilized to condition the input signal prior to the standard CMOS input.

7.3.3 Clamp Diodes

The inputs and outputs to this device have negative clamping diodes.

CAUTION

Voltages beyond the values specified in the Section 5.1 table can cause damage to the device.

The input negative-voltage and output voltage ratings may be exceeded if the input and output

clamp-current ratings are observed.

GND

Logic

Input

Output

VCC

Device

-IIK

-IOK

Figure 7-2. Electrical Placement of Clamping Diodes for Each Input and Output

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SN54LVC00A, SN74LVC00A

SCAS279S – JANUARY 1993 – REVISED MARCH 2024

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