SN74HCS00DYYR datasheet(13/31 Pages) TI

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9.2.2 Detailed Design Procedure

1. Add a decoupling capacitor from VCC to GND. The capacitor needs to be placed physically close to the

device and electrically close to both the VCC and GND pins. An example layout is shown in the Layout

section.

2. Ensure the capacitive load at the output is ≤ 50 pF. This is not a hard limit; however, it will ensure optimal

performance. This can be accomplished by providing short, appropriately sized traces from the SN74HCS00

to one or more of the receiving devices.

3. Ensure the resistive load at the output is larger than (VCC / IO(max)) Ω. This will ensure that the maximum

output current from the Absolute Maximum Ratings is not violated. Most CMOS inputs have a resistive load

measured in megaohms; much larger than the minimum calculated above.

4. Thermal issues are rarely a concern for logic gates; however, the power consumption and thermal increase

can be calculated using the steps provided in the CMOS Power Consumption and Cpd Calculation

application report.

9.2.3 Application Curves

Figure 9-2. Application Timing Diagram

10 Power Supply Recommendations

The power supply can be any voltage between the minimum and maximum supply voltage rating located in the

Recommended Operating Conditions. Each VCC terminal should have a good bypass capacitor to prevent power

disturbance. A 0.1-μF capacitor is recommended for this device. It is acceptable to parallel multiple bypass caps

to reject different frequencies of noise. The 0.1-μF and 1-μF capacitors are commonly used in parallel. The

bypass capacitor should be installed as close to the power terminal as possible for best results, as shown in the

following layout example.

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SN74HCS00

SCLS775C – DECEMBER 2019 – REVISED DECEMBER 2021

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SN74HCS00DYYR 数据表(PDF) 13 Page - Texas Instruments