The component you referred to, "SN 74HC164D R," is manufactured by Texas Instruments. It is an 8-bit shift register, and its package is typically in the SOIC (Small Outline Integrated Circuit) format, which is denoted by "DR" in the part number.
For the detailed explanation of its pin function, specifications, and the circuit principles, including the complete pinout list for the SN74HC164DR, I will break down the requested information:
SN74HC164DR: Pinout and Functionality
Package Type: SOIC-16 (16 pins)The "DR" suffix indicates that the package type is an SOIC (Small Outline Integrated Circuit) package with 16 pins.
Pin Function Descriptions: Pin Number Pin Name Description 1 QH (Out) Serial output pin. This pin holds the value of the last shifted bit. 2 QH' (Out) Inverted serial output pin. Outputs the inverted value of the QH pin. 3 GND Ground pin. It is connected to the ground of the system. 4 DS (Data Input) Data input pin for the shift register. Data is shifted in on the rising edge of the Clock . 5 CP (Clock Pulse) Clock pulse input pin. Data is shifted into the shift register on the rising edge of the clock. 6 MR (Master Reset) Active-low reset pin. When low, it resets the shift register. 7 QH2 (Output) Second bit serial output. This pin holds the shifted value of the second bit. 8 QH3 (Output) Third bit serial output. Holds the shifted value of the third bit. 9 QH4 (Output) Fourth bit serial output. Holds the shifted value of the fourth bit. 10 QH5 (Output) Fifth bit serial output. Holds the shifted value of the fifth bit. 11 QH6 (Output) Sixth bit serial output. Holds the shifted value of the sixth bit. 12 QH7 (Output) Seventh bit serial output. Holds the shifted value of the seventh bit. 13 VCC Power supply pin. It is connected to the positive voltage supply for the chip. 14 QH8 (Output) Eighth bit serial output. Holds the shifted value of the eighth bit. 15 QH' (Inverted Output) Inverted version of the QH pin output. 16 VCC Power supply pin. It connects to the positive supply voltage for the chip. Circuit Principle Overview:The SN74HC164 is a serial-in parallel-out (SIPO) shift register with an 8-bit width. It functions by shifting bits in serially on the Data Input pin (DS) with each rising edge of the clock signal (CP), and the outputs on QH1 to QH8 represent the parallel outputs of the 8-bit shift register. The MR (Master Reset) pin is used to clear all registers when it is driven low.
Frequently Asked Questions (FAQs):
Q: What is the purpose of the Master Reset (MR) pin in the SN74HC164DR? A: The MR pin is an active-low reset input. When it is low, the shift register is reset, and all output pins are set to a low state.
Q: How does the clock pulse (CP) control the shifting of data in the SN74HC164DR? A: The clock pulse (CP) is used to shift the data from the DS input to the register on each rising edge of the clock. The data moves one position each time the clock pulses.
Q: What happens when the Data Input (DS) pin receives a logic "1" signal? A: When the DS pin receives a logic "1," it shifts that "1" into the shift register at the next rising edge of the clock pulse.
Q: What is the significance of the QH output pin? A: The QH pin is the serial output pin, which holds the value of the last shifted bit in the register.
Q: Can the SN74HC164DR be used for cascading multiple shift registers? A: Yes, multiple SN74HC164DR shift registers can be cascaded by connecting the QH pin of one to the DS input of the next. This allows for more than 8 bits of parallel data.
Q: What is the function of the inverted output (QH') pin? A: The QH' pin is the inverted version of the QH output, providing the complement of the bit stored in the shift register.
Q: Can the SN74HC164DR shift data in both directions? A: No, the SN74HC164DR is a unidirectional shift register, meaning it can only shift data from serial to parallel but cannot shift parallel data back to serial.
Q: What happens if the VCC pin is not properly connected? A: If the VCC pin is not connected to the correct power supply, the device will not function correctly, and outputs may be undefined or remain at a low state.
Q: What is the maximum clock frequency for the SN74HC164DR? A: The maximum clock frequency is typically around 25 MHz depending on the operating conditions such as voltage supply and load capacitance.
Q: What is the minimum voltage required to operate the SN74HC164DR? A: The minimum supply voltage required for proper operation is 2V, and the maximum voltage is typically 6V.
Q: Is the SN74HC164DR compatible with 3.3V logic? A: Yes, the SN74HC164DR is fully compatible with 3.3V logic levels, provided the supply voltage is within the specified range.
Q: Can the SN74HC164DR be used with both TTL and CMOS logic families? A: Yes, the SN74HC164DR is compatible with both TTL and CMOS logic families.
Q: What are the output voltage levels for the SN74HC164DR? A: The output voltage levels depend on the supply voltage (VCC). For example, with a VCC of 5V, the high output will be near 5V, and the low output will be near 0V.
Q: What is the impact of increasing the clock frequency too much? A: If the clock frequency is too high, the shift register may fail to reliably shift data, or output may become unpredictable due to timing constraints.
Q: How can I interface the SN74HC164DR with a microcontroller? A: The DS input can be connected to a GPIO pin of the microcontroller, and the CP pin to a clock source. The outputs (QH1 to QH8) can be used for parallel data outputs.
Q: What happens if the DS pin is left floating? A: Leaving the DS pin floating could cause unpredictable behavior. It is important to either drive this pin high or low, or use a pull-down resistor when not in use.
Q: How does the SN74HC164DR handle noise in the input signal? A: The SN74HC164DR is designed to be robust against noise, but it is still advisable to filter noisy clock or data signals to ensure proper operation.
Q: Can I use a resistor to limit current on the output pins? A: Yes, you can use resistors to limit the current if necessary, but the output pins are designed to drive standard CMOS loads directly.
Q: What is the propagation delay of the SN74HC164DR? A: The typical propagation delay is approximately 15ns, which is the time it takes for an input signal to propagate to the corresponding output.
Q: How does the SN74HC164DR behave during a power-up event? A: During power-up, the outputs are in an undefined state until the device receives proper VCC and the reset pin is activated (if necessary).
This information provides a thorough understanding of the pin functions and the operation of the SN74HC164DR chip, including an FAQ section with typical user inquiries. If you need any further elaboration or a different format, feel free to ask!
