The part number "SN74LVC245ADWR" refers to a product manufactured by Texas Instruments. This specific part is a Octal Bus transceiver designed for high-speed data transmission and voltage level shifting. Below, I'll provide the detailed pin function specifications, circuit principles, pinout details, and frequently asked questions (FAQ).
Pin Function Specifications:
The SN74LVC245ADWR is available in a TSSOP-20 package, which has 20 pins in total. Below is a table of the pin functions for this specific part:
Pinout Table: Pin Number Pin Name Pin Function Description 1 A1 Data Input (A1) 2 A2 Data Input (A2) 3 A3 Data Input (A3) 4 A4 Data Input (A4) 5 A5 Data Input (A5) 6 A6 Data Input (A6) 7 A7 Data Input (A7) 8 A8 Data Input (A8) 9 GND Ground 10 B1 Data Output (B1) 11 B2 Data Output (B2) 12 B3 Data Output (B3) 13 B4 Data Output (B4) 14 B5 Data Output (B5) 15 B6 Data Output (B6) 16 B7 Data Output (B7) 17 B8 Data Output (B8) 18 DIR Direction Control 19 OE Output Enable 20 Vcc Positive Supply VoltageDetailed Pin Function Descriptions:
A1-A8 (Pins 1-8): These are the data input pins (A) for the device. These pins are used to send data from the source device to the bus. Each of these pins connects to a specific bit of data.
B1-B8 (Pins 10-17): These are the data output pins (B). The data sent from the A pins will be output here, depending on the direction control pin and the output enable pin.
DIR (Pin 18): The direction control pin determines the direction of data flow. If the DIR pin is high, data flows from the A pins to the B pins. If the DIR pin is low, data flows from the B pins to the A pins.
OE (Pin 19): The output enable pin allows you to control the outputs. When OE is high, the outputs (B1-B8) are in a high-impedance state. When OE is low, data can be output on the B pins.
Vcc (Pin 20): This is the positive power supply pin for the device.
GND (Pin 9): This is the ground pin. It provides the reference point for the voltage levels.
Circuit Principle:
The SN74LVC245ADWR operates as an octal bus transceiver. It allows data to be transferred between two buses in either direction based on the DIR pin. The device has high-speed capability with low-voltage CMOS logic and supports voltage levels for TTL and CMOS logic systems. The OE pin controls whether the output is active or in a high-impedance state, enabling or disabling the bus transceiver.
This part is especially useful in systems where bidirectional data transmission is necessary, such as in memory, peripheral, and microcontroller interface s. The LVC stands for Low Voltage CMOS, meaning it can operate with low supply voltage (typically 2.7V to 3.6V).
20 FAQ on the SN74LVC245ADWR:
What is the supply voltage range for the SN74LVC245ADWR? The supply voltage range for the SN74LVC245ADWR is from 2.7V to 3.6V. What is the purpose of the DIR pin in the SN74LVC245ADWR? The DIR pin controls the direction of data flow. When DIR is high, data flows from the A pins to the B pins; when low, it flows from B pins to A pins. How does the OE pin affect the device's operation? The OE pin controls whether the output pins (B1-B8) are active or in a high-impedance state. When OE is high, the outputs are in high-impedance, and when low, the outputs are active. Can I use the SN74LVC245ADWR with a 5V power supply? No, the SN74LVC245ADWR is designed to operate with a supply voltage between 2.7V and 3.6V, so 5V would exceed the device's voltage ratings. What is the function of the A1-A8 pins? The A1-A8 pins are the data input pins, where data is fed into the device for transfer to the B pins. How many data input/output channels does the SN74LVC245ADWR have? The SN74LVC245ADWR has 8 data input pins (A1-A8) and 8 data output pins (B1-B8), for a total of 16 channels. What is the maximum data transfer speed for the SN74LVC245ADWR? The maximum data transfer speed (or data rate) is specified in the datasheet as part of the device's timing characteristics, typically measured in MHz. What happens when the Vcc pin is not connected? If the Vcc pin is not connected, the device will not function, as there will be no power supply to operate the internal logic. Can the SN74LVC245ADWR be used for both unidirectional and bidirectional data transmission? Yes, the device can be used for both unidirectional and bidirectional data transmission, controlled by the DIR pin.What is the significance of the TSSOP-20 package for the SN74LVC245ADWR?
The TSSOP-20 package is a small, surface-mount package with 20 pins, ideal for compact circuit designs where space is limited.How can I protect the SN74LVC245ADWR from static discharge?
To protect the device from static discharge, you can use proper ESD (Electrostatic Discharge) handling techniques, including grounding yourself and using ESD-safe equipment.Is the SN74LVC245ADWR compatible with 5V logic?
No, it is designed for low voltage (2.7V to 3.6V), so it is not directly compatible with 5V logic systems without additional level shifting.What type of logic does the SN74LVC245ADWR support?
The SN74LVC245ADWR supports low-voltage CMOS (LVC) logic.Can I connect the A and B pins together?
No, connecting the A and B pins together could result in unpredictable behavior. The A and B buses should be connected to separate devices.What is the typical application of the SN74LVC245ADWR?
Typical applications include memory interfacing, peripheral interfacing, and any system requiring bidirectional data transfer between buses.How do I calculate the timing for data transfer?
The timing characteristics for data transfer are defined in the datasheet, including setup time, hold time, and propagation delay.What is the maximum current that can be supplied to the A and B pins?
The maximum current ratings are specified in the datasheet, typically a few milliamps per pin for reliable operation.Can the SN74LVC245ADWR be used in automotive applications?
The SN74LVC245ADWR can be used in automotive applications if the operating voltage and environmental conditions match the device's specifications.Is there a version of the SN74LVC245ADWR with more or fewer pins?
Yes, Texas Instruments also offers similar parts in different packages and pin counts, such as the 8-pin versions.How does temperature affect the SN74LVC245ADWR?
The device operates within a specified temperature range, typically from -40°C to +85°C, and performance may degrade outside this range.This concludes the detailed pinout, functional descriptions, and frequently asked questions for the SN74LVC245ADWR.