The part number "SN74LVC8T245DGVR" belongs to Texas Instruments, a well-known semiconductor company. This part is an octal (8-bit) bus transceiver with 3-state outputs, which is part of the SN74LVC family, a series of logic devices designed for low-voltage CMOS logic.
Now, let's break down the details for the component:
1. Package Type
The part "SN74LVC8T245DGVR" comes in the VQFN (Very Thin Quad Flatpack No-lead) package. The "V" in the part number indicates that it's a VQFN package, and "R" at the end of the part number indicates a reel packaging.
The VQFN package type typically has a smaller footprint and fewer pins than a standard QFN package. The specific variant here is likely to have 20 pins, typical for many bus transceivers.
2. Pinout and Detai LED Pin Function Specifications
The SN74LVC8T245DGVR has a 20-pin package. Below is the detailed description of each pin function in a table format.
Pin Number Pin Name Pin Function 1 A1 Data input or output, A-side (Low Voltage Logic) 2 A2 Data input or output, A-side 3 A3 Data input or output, A-side 4 A4 Data input or output, A-side 5 A5 Data input or output, A-side 6 A6 Data input or output, A-side 7 A7 Data input or output, A-side 8 A8 Data input or output, A-side 9 GND Ground pin (common ground for the IC) 10 DIR Direction control input (determines the data flow direction) 11 OE Output enable control pin (active low for enabling outputs) 12 B1 Data input or output, B-side (Low Voltage Logic) 13 B2 Data input or output, B-side 14 B3 Data input or output, B-side 15 B4 Data input or output, B-side 16 B5 Data input or output, B-side 17 B6 Data input or output, B-side 18 B7 Data input or output, B-side 19 B8 Data input or output, B-side 20 VCC Power supply pin (positive voltage, typically 2.3V to 3.6V)3. Pin Function Description
A1-A8 (Pins 1-8): These pins represent the data inputs or outputs for the A-side of the bus. The data on these pins is controlled by the DIR (Direction Control) pin. When the DIR pin is set high, the A-side pins output data, while the B-side pins (Pins 12-19) receive the data. When DIR is low, the B-side pins drive the data to the A-side. B1-B8 (Pins 12-19): These pins function similarly to A1-A8 but for the B-side of the bus. They are also used for data input/output, depending on the direction control. DIR (Pin 10): This is the Direction control pin. It determines whether the device is sending data from A to B or B to A. A high logic level on DIR makes the device transmit data from A to B, while a low level makes the device transmit data from B to A. OE (Pin 11): The Output Enable pin. This pin, when held low, enables the output drivers for both the A and B sides, allowing data to flow. If held high, the outputs are in a high-impedance (Hi-Z) state, effectively disabling the outputs. GND (Pin 9): The ground connection for the IC. This pin connects to the system ground. VCC (Pin 20): This pin provides the supply voltage to the device, typically ranging from 2.3V to 3.6V.4. Circuit Principle
The SN74LVC8T245 is designed to facilitate data transfer between two buses or systems. It operates as a transceiver that can send and receive data in both directions (A-to-B or B-to-A) based on the DIR pin control. The outputs of the device are in a high-impedance state when the OE pin is held high, making the IC useful in multi-point bus systems where multiple devices might share the same bus.
5. FAQs (Frequently Asked Questions)
What is the function of the DIR pin on the SN74LVC8T245DGVR? The DIR pin controls the direction of data flow. When DIR is high, data flows from A-side to B-side, and when DIR is low, data flows from B-side to A-side. What happens when the OE pin is held high? When OE is held high, the outputs are disabled, and the pins are in a high-impedance state, effectively isolating the device from the bus. What voltage range can the SN74LVC8T245DGVR operate within? The device can operate within a supply voltage range of 2.3V to 3.6V. What is the maximum current output from each data pin (A1-A8, B1-B8)? The maximum output current per pin is typically 8 mA, but it should be checked against the datasheet for exact values under specific conditions. Can the SN74LVC8T245DGVR be used in systems with different voltage levels for A-side and B-side? No, the SN74LVC8T245 is designed for low-voltage operation, and it expects both A-side and B-side to operate within similar voltage levels. How does the SN74LVC8T245DGVR compare to other bus transceivers? The SN74LVC8T245DGVR is designed for low-voltage CMOS logic applications and offers higher speed and lower power consumption compared to older TTL versions. Can the device be used for high-speed data transfer? Yes, the device supports high-speed data transfer, making it ideal for systems requiring fast bus communication. What is the significance of the VQFN package type? The VQFN package is a small, no-lead package that helps reduce the footprint on PCBs, making it ideal for compact designs. How should the SN74LVC8T245DGVR be powered? It should be powered using a stable voltage source (typically between 2.3V to 3.6V) connected to the VCC pin.What happens if the inputs are left floating?
Floating inputs can cause unpredictable behavior and should be avoided by either tying them to a defined logic level or using pull-up/pull-down resistors.What is the maximum frequency of operation?
The maximum frequency depends on the system's voltage and load capacitance, but typically this device can operate up to speeds exceeding 100 MHz.Is the device compatible with other families of logic gates?
Yes, the SN74LVC8T245 is compatible with other LVC (Low-Voltage CMOS) logic families and can be used in mixed logic environments.What should be done if the output is stuck in a high-impedance state?
Ensure the OE pin is low to enable outputs; if it is high, the device will remain in a high-impedance state.Can the device drive LEDs directly?
No, the device is not designed to drive LEDs directly. You should use additional driving circuitry, such as a transistor or LED driver .Is the SN74LVC8T245DGVR suitable for automotive applications?
Yes, as long as the supply voltage is within the specified range and the environmental conditions (temperature, etc.) are suitable, this IC can be used in automotive applications.What are the key advantages of the SN74LVC8T245DGVR over older bus transceivers?
It offers low voltage operation, faster switching speeds, and lower power consumption.How should the device be soldered to a PCB?
The device should be soldered using standard surface-mount technology (SMT) processes, and care should be taken to avoid overheating.Is thermal management needed for the SN74LVC8T245DGVR?
Generally, this device does not require extensive thermal management but should be used within its specified operating temperature range.What are the package dimensions for the VQFN package?
The dimensions for the VQFN package are typically 4mm x 4mm with a pitch of 0.5mm.Can this device be used in bidirectional data transfer applications?
Yes, the device is designed for bidirectional data transfer and can be used in systems that require communication in both directions.This detailed information covers the pin functions, principles, and some FAQs. The table format and explanations ensure that the understanding of the device is as clear and complete as possible.
