SN65HVD235DR Detailed explanation of pin function specifications and circuit principle instructions

The part number "SN65HVD235DR" belongs to Texas Instruments (TI). This component is an RS-485 transceiver , and its function is to facilitate communication in differential signaling systems, commonly used in industrial and data communication environments.

Packaging

The "SN65HVD235DR" is available in a SOIC-8 (Small Outline Integrated Circuit, 8 pins) package. It's designed to handle data transmission with high noise immunity and low Power consumption.

Detailed Pin Function Specifications for SN65HVD235DR

The SN65HVD235DR is a 8-pin device in the SOIC-8 package. Below is the detailed description of each pin function.

Pin Number Pin Name Pin Function 1 RO Receiver Output. This pin outputs the received data signal. It is the logic-level representation of the differential signal on the bus. It is active low (if the transceiver receives a low differential signal). 2 RE Receiver Enable. This pin controls the receiver section of the transceiver. When RE is low, the receiver is enabled, allowing the device to receive data. When RE is high, the receiver is disabled, and the output (RO) is in a high-impedance state. 3 DE Driver Enable. This pin controls the driver section of the transceiver. When DE is high, the driver is enabled and can send data on the bus. When DE is low, the driver is disabled, and the bus is left in a high-impedance state. 4 DI Driver Input. This pin is used for inputting data that will be transmitted to the bus. When the driver is enabled, the data present on DI will be transmitted differentially on the bus. 5 A A (Non-Inverting) Differential Bus Pin. This pin is one of the two bus terminals for the differential signaling. It should be connected to the positive side of the differential pair. 6 B B (Inverting) Differential Bus Pin. This pin is the second bus terminal for the differential signaling. It should be connected to the negative side of the differential pair. 7 VCC Power Supply Pin. This pin should be connected to the positive supply voltage, typically 3.3V or 5V depending on the application. 8 GND Ground Pin. This pin should be connected to the ground of the circuit.

Circuit Principle Instructions

The SN65HVD235DR is used for differential data transmission over a long distance with higher noise immunity compared to single-ended signals. The transceiver can function as both a transmitter and a receiver. It uses the RS-485 standard, which allows multiple devices (up to 32) to be connected on the same differential bus.

In the transceiver, when the driver section is enabled (DE pin high), data from the DI pin is transmitted over the A and B pins (differential signaling). When the receiver section is enabled (RE pin low), the transceiver listens to the differential bus and converts the signals into a logic-level representation at the RO pin.

Important Considerations:

The A and B pins should be properly terminated with a resistor to ensure proper differential signaling. When using multiple transceivers on the same bus, biasing resistors may be required to ensure the bus remains in a known state when no device is actively driving the bus.

Frequently Asked Questions (FAQ) - SN65HVD235DR

What is the purpose of the "RO" pin in the SN65HVD235DR? The "RO" pin provides the logic-level output of the received differential signal. It is used to read the data received by the receiver. What does the "RE" pin do in the SN65HVD235DR? The "RE" pin enables or disables the receiver section of the transceiver. When low, the receiver is active, and when high, it is disabled. Can I use the SN65HVD235DR for single-ended communication? No, the SN65HVD235DR is designed for differential signaling and cannot be used for single-ended communication. How do I enable the driver of the SN65HVD235DR? To enable the driver, set the "DE" pin high. This will allow the device to drive the differential signals onto the A and B bus pins. What should I connect the A and B pins to? The A and B pins should be connected to the differential pair of the RS-485 bus, with A being the non-inverting and B the inverting side. What happens if the "DE" pin is set low? If the "DE" pin is low, the driver is disabled, and the bus is left in a high-impedance state. Can I use the SN65HVD235DR with a 5V power supply? Yes, the SN65HVD235DR can operate with a 5V power supply, but it can also operate with a 3.3V supply depending on your application. What is the maximum data rate for the SN65HVD235DR? The maximum data rate for the SN65HVD235DR is typically 10 Mbps. Is the SN65HVD235DR suitable for long-distance communication? Yes, the SN65HVD235DR is designed for long-distance communication with the RS-485 standard, which supports distances up to 4000 feet (1.2 kilometers) at lower data rates.

How do I terminate the RS-485 bus for proper operation?

To ensure proper communication, terminate the A and B lines at both ends of the bus with a resistor (typically 120Ω) matching the characteristic impedance of the bus.

What is the significance of the RE pin in the SN65HVD235DR?

The RE pin controls whether the receiver is active. When RE is low, the receiver is enabled to receive data from the bus.

Can multiple SN65HVD235DR devices be connected to the same bus?

Yes, multiple devices can be connected to the same RS-485 bus. The RS-485 standard supports up to 32 transceivers on a single bus.

What should I do if the data on the bus becomes corrupted or unreliable?

Check the termination of the bus, ensure the proper voltage levels on the VCC and GND pins, and ensure that no more than 32 transceivers are connected to the bus.

What is the difference between A and B pins in the SN65HVD235DR?

The A and B pins represent the differential signal lines. A is the non-inverting pin, and B is the inverting pin, providing differential data transmission.

Can the SN65HVD235DR handle high-speed communication?

The SN65HVD235DR is capable of data rates up to 10 Mbps, making it suitable for medium to high-speed applications.

What happens when the VCC pin is not connected properly?

If the VCC pin is not properly connected, the device will not function, and there will be no communication on the bus.

How can I prevent noise interference when using the SN65HVD235DR?

Properly terminate the bus, use twisted pair wires for the differential signal, and ensure proper grounding to reduce noise interference.

What is the role of the GND pin in the SN65HVD235DR?

The GND pin is the ground reference for the transceiver. It should be connected to the ground of your circuit to ensure proper signal levels.

Can I use the SN65HVD235DR in a 3.3V system?

Yes, the SN65HVD235DR can operate in 3.3V systems, but be sure the signal levels are compatible with other devices on the bus.

What are the key features of the SN65HVD235DR?

The SN65HVD235DR is a low-power, high-speed RS-485 transceiver with a wide voltage range (3.3V to 5V), robust noise immunity, and the ability to drive and receive data over long distances.

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