SN74HCS238D datasheet(9/18 Pages) TI

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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).

The Schmitt-trigger input architecture provides hysteresis as defined by ΔVT in the Electrical Characteristics

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.

GND

Logic

Input

Output

VCC

Device

-IIK

+IIK

+IOK

-IOK

Figure 8-2. Electrical Placement of Clamping Diodes for Each Input and Output

8.4 Device Functional Modes

Function Table lists the functional modes of the SN74HCS238.

Table 8-1. Function Table

INPUTS(1)

OUTPUTS

(1)

H = High Voltage Level, L = Low Voltage Level, X = Don't Care

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SN74HCS238

SCLS835 – SEPTEMBER 2020

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SN74HCS238D Datasheet(PDF) 9 Page - Texas Instruments