SN74HC191D datasheet by Texas Instruments

SN74HC191D Frequently Asked Questions (FAQs)

• What is the maximum clock frequency that the SN74HC191D can handle?
  The maximum clock frequency of the SN74HC191D is 30 MHz, but it can vary depending on the operating voltage and load capacitance. It's recommended to check the timing characteristics in the datasheet for specific frequency limits.
• How do I ensure that the SN74HC191D is properly reset during power-up?
  To ensure proper reset, connect the MR (Master Reset) pin to a pull-up resistor and a capacitor to VCC. This will ensure that the device is reset during power-up and holds the reset state until the capacitor is fully charged.
• What is the recommended operating voltage range for the SN74HC191D?
  The recommended operating voltage range for the SN74HC191D is 2V to 6V, with a typical operating voltage of 5V. Operating the device outside of this range may affect its performance and reliability.
• Can I use the SN74HC191D in a 3.3V system?
  Yes, the SN74HC191D can be used in a 3.3V system, but it's essential to ensure that the input signals are within the recommended voltage range (VCC - 0.5V to VCC + 0.5V) to maintain proper operation.
• How do I handle the asynchronous clear input (CLR) in my design?
  The asynchronous clear input (CLR) should be tied to VCC through a pull-up resistor if not used. If used, ensure that the CLR signal is synchronized with the clock signal to avoid unintended clearing of the counter.