SN54HC191J datasheet by Texas Instruments

SN54HC191J Frequently Asked Questions (FAQs)

• What is the maximum clock frequency that the SN54HC191J can handle?
  The maximum clock frequency of the SN54HC191J is 40 MHz, but it can vary depending on the operating voltage and temperature. It's recommended to check the timing characteristics in the datasheet for specific frequency limits.
• How do I ensure that the SN54HC191J 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 SN54HC191J?
  The recommended operating voltage range for the SN54HC191J 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 SN54HC191J in a 3.3V system?
  Yes, the SN54HC191J can be used in a 3.3V system, but it's essential to ensure that the input signals are within the recommended voltage range (Vih = 2.4V, Vil = 0.8V) and that the output signals are compatible with the 3.3V system.
• How do I handle the asynchronous clear input (CLR) in the SN54HC191J?
  The CLR input is an asynchronous clear input that resets the counter when it's low. To ensure proper operation, CLR should be synchronized with the clock signal to avoid metastability issues. It's recommended to use a flip-flop or a synchronizer to synchronize the CLR signal with the clock.