The component you mentioned, "SN 74HC245PW R," is part of the Texas Instruments (TI) product line. It is a 74HC245 series octal bus transceiver with 3-state outputs. This IC belongs to the family of HC (High-speed CMOS) logic devices.
Specifications for SN74HC245PWR:
1. Package Type: The SN74HC245PWR is a TSSOP-20 package (Thin Shrink Small Outline Package) with 20 pins. Pin Count: 20 pins (also referred to as TSSOP-20 package). 2. Pin Function List:The following is the detai LED pinout of the SN74HC245PWR package, describing the functionality of each of the 20 pins:
Pin Number Pin Name Pin Function 1 A1 Data input for the high byte (DIP1). 2 A2 Data input for the high byte (DIP2). 3 A3 Data input for the high byte (DIP3). 4 A4 Data input for the high byte (DIP4). 5 A5 Data input for the high byte (DIP5). 6 A6 Data input for the high byte (DIP6). 7 A7 Data input for the high byte (DIP7). 8 A8 Data input for the high byte (DIP8). 9 GND Ground connection. 10 OE Output Enable Pin: Enables or disables the outputs. 11 B1 Data output for the high byte (DIP1). 12 B2 Data output for the high byte (DIP2). 13 B3 Data output for the high byte (DIP3). 14 B4 Data output for the high byte (DIP4). 15 B5 Data output for the high byte (DIP5). 16 B6 Data output for the high byte (DIP6). 17 B7 Data output for the high byte (DIP7). 18 B8 Data output for the high byte (DIP8). 19 VCC Power supply input. 20 GND Ground connection (second ground pin). 3. Circuit Principles and Functionality:The SN74HC245PWR is an octal bus transceiver with 3-state outputs. This means that it has eight data inputs (A1-A8) and eight data outputs (B1-B8), which can be used for bi-directional data transfer. It also features an output enable pin (OE), which is used to control the output of the device. When OE is low, the outputs are enabled; when OE is high, the outputs are placed in a high-impedance state, effectively isolating the outputs from the bus.
This IC is commonly used in data bus applications for interfacing microcontrollers with peripheral devices or systems where high-speed data transfer is required.
4. FAQs (Frequently Asked Questions):Q1: What is the function of the OE (Output Enable) pin in SN74HC245PWR?
A1: The OE pin (pin 10) controls the output state of the device. When OE is low, the outputs (B1 to B8) are enabled. When OE is high, the outputs are in a high-impedance state, which effectively isolates the outputs from the bus.
Q2: How many data lines are there in SN74HC245PWR, and what are their functions?
A2: The SN74HC245PWR has 16 data lines in total: 8 input lines (A1 to A8) and 8 output lines (B1 to B8). The input lines receive data, while the output lines transmit the data.
Q3: What is the voltage supply range for the SN74HC245PWR?
A3: The SN74HC245PWR operates with a voltage supply range of 2V to 6V for VCC (Pin 19).
Q4: What type of logic family does the SN74HC245PWR belong to?
A4: The SN74HC245PWR is part of the 74HC (High-speed CMOS) logic family, which is designed for high-speed and low-power consumption applications.
Q5: Can the SN74HC245PWR be used in both directions for data transfer?
A5: Yes, the SN74HC245PWR is a bi-directional transceiver, meaning that it can both receive and transmit data through the A and B lines, depending on the direction set by the OE pin.
Q6: How does the SN74HC245PWR handle logic levels?
A6: The SN74HC245PWR supports CMOS logic levels, which means it is compatible with both TTL (Transistor-Transistor Logic) and CMOS logic devices. It ensures proper voltage levels for high and low logic states.
Q7: What is the maximum data transfer rate for the SN74HC245PWR?
A7: The SN74HC245PWR can operate at speeds up to 25 MHz under typical operating conditions.
Q8: What is the significance of the 3-state outputs in SN74HC245PWR?
A8: The 3-state outputs allow the SN74HC245PWR to effectively interface with multiple devices on a data bus without causing signal conflicts, by enabling or disabling its outputs via the OE pin.
Q9: What is the temperature range for the SN74HC245PWR?
A9: The SN74HC245PWR is rated for an operating temperature range of -40°C to +125°C.
Q10: Can the SN74HC245PWR be used in high-voltage circuits?
A10: The SN74HC245PWR is not designed for use in high-voltage circuits; it operates within a voltage supply range of 2V to 6V, and higher voltage usage could damage the device.
Q11: How is the SN74HC245PWR packaged?
A11: The SN74HC245PWR comes in a TSSOP-20 package, a 20-pin thin shrink small outline package suitable for surface-mount technology.
Q12: What is the power consumption of the SN74HC245PWR?
A12: The SN74HC245PWR consumes very low power, typically with a supply current of 2 µA during static conditions (with no data transfer).
Q13: Can I use the SN74HC245PWR to drive LEDs?
A13: The SN74HC245PWR is not designed to directly drive LEDs, as it is a logic-level transceiver. If needed, a current-limiting resistor or a driver circuit would be required.
Q14: What is the maximum current allowed per pin in SN74HC245PWR?
A14: The maximum current allowed per pin for the SN74HC245PWR is typically 6 mA for each input and output pin.
Q15: What is the logic level for a high and low signal in SN74HC245PWR?
A15: A high signal is typically above 2V for a VCC of 5V, and a low signal is below 0.8V.
Q16: Can the SN74HC245PWR be used for 5V systems?
A16: Yes, the SN74HC245PWR can operate in 5V systems, and it is commonly used in such systems.
Q17: How is the SN74HC245PWR typically used in circuits?
A17: The SN74HC245PWR is used in data bus applications, often between microcontrollers and peripherals, allowing bidirectional data flow with high-speed capabilities.
Q18: What is the significance of the "PWR" in the part number SN74HC245PWR?
A18: The "PWR" in the part number indicates that the device is packaged in a TSSOP-20 package suitable for surface-mount installation.
Q19: What happens if I leave the OE pin floating?
A19: Leaving the OE pin floating can cause unpredictable behavior, so it should always be connected to a logic high or low level to ensure reliable output operation.
Q20: Can I use SN74HC245PWR in a 3.3V logic circuit?
A20: Yes, the SN74HC245PWR can operate in a 3.3V logic circuit, as it supports logic level voltage ranges that are compatible with 3.3V systems.
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