SN74LS191DR datasheet by Texas Instruments

SN74LS191DR Frequently Asked Questions (FAQs)

• What is the maximum clock frequency that the SN74LS191DR can handle?
  The maximum clock frequency of the SN74LS191DR is 25 MHz, but it can vary depending on the operating voltage and load capacitance.
• How do I ensure that the SN74LS191DR 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 remains in a known state.
• What is the recommended operating voltage range for the SN74LS191DR?
  The recommended operating voltage range for the SN74LS191DR is 4.75V to 5.25V, but it can operate from 4.5V to 5.5V with reduced performance.
• How do I handle the asynchronous clear input (CLR) in the SN74LS191DR?
  The CLR input should be synchronized with the clock signal to avoid metastability issues. It's recommended to use a flip-flop or a synchronizer circuit to synchronize the CLR input with the clock signal.
• What is the maximum input voltage that the SN74LS191DR can tolerate?
  The maximum input voltage that the SN74LS191DR can tolerate is 7V, but it's recommended to keep the input voltage within the recommended operating voltage range to ensure proper operation.