74HC164D Detailed explanation of pin function specifications and circuit principle instructions

The component you're asking about, "74HC164D," is a high-speed CMOS (HC) logic shift register integrated circuit (IC), manufactured by Nexperia (formerly part of Philips, and now under Nexperia).

74HC164D Pinout and Explanation:

Package Type:

The "D" suffix in the "74HC164D" refers to the SOIC-14 package (Small Outline Integrated Circuit with 14 pins). The 74HC164 is a 14-pin IC.

Here’s a detailed list of each pin’s function:

Pin Number Pin Name Description 1 Q1 Output pin 1. It provides the shifted logic data output. 2 Q2 Output pin 2. It provides the shifted logic data output. 3 Q3 Output pin 3. It provides the shifted logic data output. 4 Q4 Output pin 4. It provides the shifted logic data output. 5 Q5 Output pin 5. It provides the shifted logic data output. 6 Q6 Output pin 6. It provides the shifted logic data output. 7 Q7 Output pin 7. It provides the shifted logic data output. 8 GND Ground (0V) connection pin for the IC. 9 DS Data Serial input. This is where data enters the shift register. 10 MR Master Reset (active low). It clears the outputs (Q1-Q7). 11 CLK Clock pin for the shift register, it triggers the shifting operation. 12 QH' Output pin QH (complement of Q7) for a serial output. 13 QH Serial output pin. This is the last output in the chain of data. 14 VCC Power supply pin for the IC. Typically +5V.

General Operating Principle:

The 74HC164 is a serial-in, parallel-out shift register. Data is shifted in serially via the DS (Data Serial) pin and clocked in with the rising edge of the CLK (Clock) pin. After each clock pulse, the input data moves one step through the register, and the outputs (Q1-Q7) reflect the shifted data in parallel. The MR (Master Reset) pin clears all the outputs when activated low.

Pin Function FAQ (20 Common Questions):

Q1: What does the DS pin do in the 74HC164D? A1: The DS pin is the serial data input for the 74HC164D. It is where data is entered bit by bit to be shifted through the register.

Q2: What happens when the CLK pin is triggered in the 74HC164D? A2: The CLK pin triggers the shift operation, causing the data in the shift register to move one position to the right with each clock pulse.

Q3: Can I use 74HC164D without the MR pin? A3: No, the MR pin is essential because it allows you to reset the outputs to a known state when needed. If left unconnected, it can cause unpredictable behavior.

Q4: What happens when the MR pin is set low in the 74HC164D? A4: When the MR pin is low (active low), it resets all outputs (Q1-Q7) to a logic low state.

Q5: How many output pins does the 74HC164D have? A5: The 74HC164D has seven output pins, labeled Q1 through Q7. These pins reflect the shifted data.

Q6: What is the significance of the QH' pin on the 74HC164D? A6: The QH' pin is the complement of the Q7 pin, providing a serial output of the shifted data.

Q7: How do I use the 74HC164D in a circuit? A7: To use the 74HC164D, you need to provide data at the DS pin, clock it in with the CLK pin, and read the parallel data at Q1-Q7 or the serial output at QH.

Q8: What is the supply voltage for the 74HC164D? A8: The 74HC164D typically operates at a supply voltage of +5V (VCC pin), though it can function at lower voltages within the specified range.

Q9: Can I chain multiple 74HC164D ICs together? A9: Yes, you can cascade multiple 74HC164D ICs by connecting the QH pin of one IC to the DS pin of the next IC.

Q10: What does the GND pin represent in the 74HC164D? A10: The GND pin is the ground connection and serves as the reference voltage for the IC.

Q11: Can I use the 74HC164D in high-speed applications? A11: Yes, the 74HC164D is a high-speed CMOS shift register, suitable for many digital circuits where fast serial-to-parallel data conversion is needed.

Q12: How do I know when to change the data input? A12: Data should be changed at the DS pin just before or between clock pulses on the CLK pin to ensure proper shifting.

Q13: What happens if the CLK pin has no signal? A13: If the CLK pin does not receive a signal, the data in the shift register will not shift, and the outputs will remain static.

Q14: What is the maximum clock frequency of the 74HC164D? A14: The 74HC164D typically operates at frequencies up to 25 MHz, depending on voltage and temperature conditions.

Q15: What should I do if my 74HC164D isn’t outputting data? A15: Check the power supply, ensure the CLK pin is receiving pulses, and verify that the MR pin is not active low.

Q16: Can I use the 74HC164D in 3.3V circuits? A16: Yes, but ensure that the logic levels are within the acceptable range for the IC’s inputs and outputs, as specified in the datasheet.

Q17: How do I reset the 74HC164D? A17: To reset the 74HC164D, set the MR pin low to clear all output pins.

Q18: What does the Q1-Q7 output pins represent? A18: The Q1-Q7 output pins represent the shifted data after each clock pulse. Each pin reflects the state of the shift register at that position.

Q19: Can I use the 74HC164D for bidirectional data? A19: No, the 74HC164D is designed for unidirectional data transfer (serial input to parallel output).

Q20: What is the function of the VCC pin? A20: The VCC pin is the positive power supply pin for the IC, typically powered by +5V.

This should give you a comprehensive overview of the 74HC164D shift register. Feel free to ask if you need further clarification!