74HC573D Detailed explanation of pin function specifications and circuit principle instructions
The " 74HC573D " is a high-speed CMOS logic IC from NXP Semiconductors, part of the 74HC series. Specifically, it is an octal D-type transparent latch with 3-state outputs.
Let's break down the requested information about the device:
1. Package Type and Pinout Details
The 74HC573D comes in a 20-pin Dual In-line Package (DIP), a widely used through-hole package. It can also be available in other package types (e.g., SOIC), but for this explanation, we'll focus on the DIP-20 package. Here are the full pinout functions for this specific device:
Pin Function Table (DIP-20)
Pin Number Pin Name Pin Function Description 1 Q0 Output for Data Bit 0. When the latch is enabled, the data from the corresponding input (D0) is passed to Q0. 2 Q1 Output for Data Bit 1. When the latch is enabled, the data from the corresponding input (D1) is passed to Q1. 3 Q2 Output for Data Bit 2. When the latch is enabled, the data from the corresponding input (D2) is passed to Q2. 4 Q3 Output for Data Bit 3. When the latch is enabled, the data from the corresponding input (D3) is passed to Q3. 5 Q4 Output for Data Bit 4. When the latch is enabled, the data from the corresponding input (D4) is passed to Q4. 6 Q5 Output for Data Bit 5. When the latch is enabled, the data from the corresponding input (D5) is passed to Q5. 7 Q6 Output for Data Bit 6. When the latch is enabled, the data from the corresponding input (D6) is passed to Q6. 8 Q7 Output for Data Bit 7. When the latch is enabled, the data from the corresponding input (D7) is passed to Q7. 9 GND Ground. Connect this pin to the ground of your circuit. 10 Q0 Output for Data Bit 0 (repeated). 11 Q1 Output for Data Bit 1 (repeated). 12 Q2 Output for Data Bit 2 (repeated). 13 Q3 Output for Data Bit 3 (repeated). 14 Q4 Output for Data Bit 4 (repeated). 15 Q5 Output for Data Bit 5 (repeated). 16 Q6 Output for Data Bit 6 (repeated). 17 Q7 Output for Data Bit 7 (repeated). 18 LE Latch Enable. When this pin is high, data from the inputs (D0 to D7) is passed to the outputs. When low, data is latched, and outputs reflect the latched data. 19 D7 Data Input for Bit 7. This pin is part of the 8-bit data input to the latch. 20 D0 Data Input for Bit 0. This pin is part of the 8-bit data input to the latch.2. Basic Circuit Operation and Principle
The 74HC573D operates as an octal transparent latch with 3-state outputs. The latch captures the data from the inputs (D0–D7) and holds it on the output pins (Q0–Q7) when the latch enable (LE) pin is low. If the latch enable (LE) is high, the outputs will reflect the values from the inputs, continuously updating.
The 3-state output configuration means that each output can be placed in a high-impedance state, which is useful for bus systems where multiple devices may need to share a common data line without interfering with each other.
LE (Latch Enable): Controls whether the data is passed to the outputs or latched. High enables transparent mode (data flows to outputs), while low latches the data. Q0–Q7: Output pins that carry the latched data. D0–D7: Data inputs that receive the data to be latched. GND: Ground pin.3. 20 Common FAQ for 74HC573D
Q: What is the function of the 74HC573D chip? A: The 74HC573D is an octal D-type latch with 3-state outputs, used for storing and transferring data.
Q: What package does the 74HC573D come in? A: It comes in a 20-pin DIP package, but can also be available in other package types.
Q: How many data inputs does the 74HC573D have? A: It has 8 data inputs, named D0 to D7.
Q: What is the latch enable (LE) pin? A: The LE pin controls whether data is passed to the output pins or latched. When low, the data is latched; when high, data is passed to the output.
Q: What happens when LE is high? A: When LE is high, the latch is transparent, and data from the D inputs is immediately passed to the Q outputs.
Q: Can the outputs of 74HC573D be in a high-impedance state? A: Yes, the outputs can be placed in a high-impedance state, which is ideal for bus systems.
Q: How many outputs does the 74HC573D have? A: It has 8 outputs, named Q0 to Q7.
Q: Is there any internal logic to control the data latching? A: Yes, the LE pin controls the latching operation.
Q: What does the "D" in 74HC573D stand for? A: The "D" refers to the type of latch—specifically, a D-type latch.
Q: Can the 74HC573D be used for data storage in microcontroller circuits? A: Yes, it can be used to store and transfer data in microcontroller circuits.
Q: What voltage range does the 74HC573D support? A: The 74HC573D operates typically between 2V to 6V.
Q: How does the 74HC573D differ from other 74HC series latches? A: It is an octal latch, meaning it has 8 bits of data, and it has 3-state outputs.
Q: Is the 74HC573D used in high-speed applications? A: Yes, the 74HC573D is designed for high-speed digital logic applications.
Q: What is the maximum operating frequency of the 74HC573D? A: The maximum operating frequency depends on the voltage level but can reach up to 25 MHz at 5V.
Q: What is the purpose of the 3-state output on the 74HC573D? A: The 3-state output allows multiple devices to share the same data bus without interfering with each other.
Q: What happens if the LE pin is left floating? A: It’s recommended not to leave the LE pin floating, as it may lead to unpredictable behavior.
Q: How is the 74HC573D used in data bus systems? A: The 74HC573D’s 3-state outputs allow it to be connected to a shared data bus, with its outputs only active when needed.
Q: What is the maximum current the 74HC573D can supply at the output pins? A: The 74HC573D can typically source or sink about 6 mA per output pin.
Q: Does the 74HC573D have internal pull-up resistors? A: No, the device does not have internal pull-up resistors, so external pull-ups may be needed in some configurations.
Q: Can I use the 74HC573D with a 3.3V system? A: Yes, it is compatible with 3.3V systems, but be mindful of the voltage levels on the outputs.
4. Conclusion
The 74HC573D is a versatile IC with a variety of uses in digital electronics, especially in systems where data needs to be latched and transmitted with 3-state outputs. The detailed pinout and operation make it highly suited for bus communication and other applications requiring transparent latching.
