SN74LS90D datasheet by Texas Instruments

SN74LS90D Frequently Asked Questions (FAQs)

• What is the maximum clock frequency that the SN74LS90D can handle?
  The maximum clock frequency of the SN74LS90D is 2 MHz, but it can vary depending on the specific application and operating conditions.
• How do I ensure that the SN74LS90D is properly powered and decoupled?
  To ensure proper operation, the SN74LS90D should be powered with a stable 5V supply, and decoupling capacitors (e.g., 0.1uF and 10uF) should be placed close to the device to filter out noise and voltage spikes.
• What is the maximum output current that the SN74LS90D can sink or source?
  The SN74LS90D can sink or source up to 16mA of current per output pin, but it's recommended to limit the current to 10mA or less to ensure reliable operation.
• How do I handle the asynchronous reset input (R) on the SN74LS90D?
  The asynchronous reset input (R) should be tied to VCC through a pull-up resistor (e.g., 1kΩ) to ensure that the device is properly reset. A capacitor (e.g., 100nF) can also be added to filter out noise on the reset line.
• Can I use the SN74LS90D in a 3.3V system?
  The SN74LS90D is designed for 5V operation, but it can be used in a 3.3V system with some limitations. However, the device's performance and functionality may be affected, and it's recommended to consult the datasheet and application notes for specific guidance.