The SN74ACT244DWR is a product from Texas Instruments (TI), which is a global semiconductor manufacturer. It is an octal buffer/line driver with 3-state outputs and operates as a part of their 74ACT series.
Packaging of SN74ACT244DWR:
The DWR suffix indicates that the device is in a TSSOP (Thin Shrink Small Outline Package), specifically a 20-pin TSSOP package.Pin Function Specifications:
Below is a detailed explanation of the pin functions for the SN74ACT244DWR based on its 20-pin TSSOP package.
Pin Number Pin Name Pin Type Pin Function Description 1 O1 Output 3-state output for data line 1 (Y1). 2 O2 Output 3-state output for data line 2 (Y2). 3 O3 Output 3-state output for data line 3 (Y3). 4 O4 Output 3-state output for data line 4 (Y4). 5 O5 Output 3-state output for data line 5 (Y5). 6 O6 Output 3-state output for data line 6 (Y6). 7 O7 Output 3-state output for data line 7 (Y7). 8 O8 Output 3-state output for data line 8 (Y8). 9 GND Ground Ground pin, must be connected to the system ground. 10 DIR Input Direction control pin, determines whether the outputs are active or in high impedance. 11 A1 Input Data input line 1 (A1). 12 A2 Input Data input line 2 (A2). 13 A3 Input Data input line 3 (A3). 14 A4 Input Data input line 4 (A4). 15 A5 Input Data input line 5 (A5). 16 A6 Input Data input line 6 (A6). 17 A7 Input Data input line 7 (A7). 18 A8 Input Data input line 8 (A8). 19 Vcc Power Supply voltage, must be connected to the system power source (typically 5V). 20 /OE Input Output Enable pin, active low; when LOW, the outputs are enabled, when HIGH, outputs are high impedance.Circuit Principle Instruction:
The SN74ACT244DWR is a high-speed octal buffer with 3-state outputs designed to improve signal integrity and data transfer in digital circuits. It is widely used in situations where multiple devices need to share the same bus or data lines, such as in microprocessor interface s, memory buffers, and data multiplexers. The IC buffers data from 8 input lines (A1 to A8) and drives 8 output lines (Y1 to Y8). When the /OE (Output Enable) pin is HIGH, the output pins go into a high-impedance state, effectively isolating them from the circuit, which is crucial for bus systems that share data lines between devices. The DIR (Direction) pin determines whether the data is driven from the input lines to the output lines (when DIR is LOW) or vice versa (when DIR is HIGH). This makes the IC versatile for bidirectional data flow management.
FAQs:
Below are 20 frequently asked questions (FAQs) about the SN74ACT244DWR.
Q: What is the operating voltage range for the SN74ACT244DWR? A: The operating voltage range is typically 4.5V to 5.5V.
Q: How many pins are in the SN74ACT244DWR package? A: The SN74ACT244DWR comes in a 20-pin TSSOP package.
Q: What is the purpose of the /OE pin in the SN74ACT244DWR? A: The /OE pin is the Output Enable pin. When LOW, it enables the output lines; when HIGH, it puts the output lines into a high-impedance state.
Q: How do I control the data flow with the DIR pin? A: The DIR pin controls the direction of data flow. When LOW, data from A1-A8 is driven to Y1-Y8; when HIGH, data from Y1-Y8 is driven to A1-A8.
Q: Is the SN74ACT244DWR compatible with 3.3V logic levels? A: The device operates best with 5V logic levels but can tolerate 3.3V logic for inputs. However, for proper output voltage levels, a 5V supply is recommended.
Q: What is the maximum current that each output pin can source or sink? A: Each output pin can source or sink up to 24mA.
Q: Can the SN74ACT244DWR be used for both input and output data? A: Yes, the SN74ACT244DWR is a bidirectional buffer, and the DIR pin controls the direction of the data flow.
Q: What is the function of the Vcc pin on the SN74ACT244DWR? A: The Vcc pin provides the supply voltage to the device and must be connected to the positive power rail (typically 5V).
Q: What is the typical propagation delay for the SN74ACT244DWR? A: The typical propagation delay time is 5ns (nanoseconds) for both high-to-low and low-to-high transitions.
Q: How do I connect the GND pin? A: The GND pin must be connected to the ground of the system to complete the circuit.
Q: Can the SN74ACT244DWR be used in a system with mixed 5V and 3.3V components? A: Yes, the device can work in mixed voltage systems as long as the voltage levels are within the specified range for input and output logic.
Q: Can I use the SN74ACT244DWR to drive a large capacitive load? A: The SN74ACT244DWR is not intended to drive large capacitive loads directly. A series resistor or buffer might be necessary.
Q: What happens when the /OE pin is HIGH? A: When the /OE pin is HIGH, all output pins go into a high-impedance state, effectively disconnecting the outputs from the circuit.
Q: How should I handle unused pins in the SN74ACT244DWR? A: Unused input pins should be tied to either HIGH or LOW to avoid floating inputs, and unused output pins should not affect the operation if they are left unconnected when /OE is HIGH.
Q: What is the difference between the SN74ACT244 and SN74ACT245? A: The SN74ACT244 is an octal buffer with a single direction (data flows from inputs to outputs), while the SN74ACT245 has bi-directional capability, allowing data to flow both ways.
Q: Can I cascade multiple SN74ACT244DWR devices? A: Yes, you can cascade multiple devices by connecting the outputs to the inputs of the next device, ensuring the /OE and DIR pins are properly controlled.
Q: What is the maximum data rate supported by the SN74ACT244DWR? A: The device supports data rates up to 125 MHz, making it suitable for high-speed digital circuits.
Q: How does the 3-state output work in the SN74ACT244DWR? A: The 3-state output allows the device to either drive a signal, be in a high-impedance state, or be disconnected, which is crucial in bus systems.
Q: Can I use the SN74ACT244DWR for level shifting applications? A: The device is not designed specifically for level shifting but can be used in systems where voltage compatibility between 5V logic and 3.3V systems is needed.
Q: What is the recommended operating temperature range for the SN74ACT244DWR? A: The recommended operating temperature range is 0°C to 70°C for commercial-grade devices.
This information provides a detailed understanding of the SN74ACT244DWR chip's functions, pins, usage, and common queries. Let me know if you need further details!
