SN75150D datasheet by Texas Instruments

SN75150D Frequently Asked Questions (FAQs)

• What is the maximum cable length that can be used with the SN75150D?
  The maximum cable length depends on the data rate and the type of cable used. As a general rule, the maximum cable length for RS-485 is around 4000 feet (1219 meters) at a data rate of 100 kbps. However, this can be affected by factors such as cable quality, noise, and termination.
• How do I terminate the RS-485 bus to prevent signal reflections?
  To prevent signal reflections, a termination resistor (typically 120 ohms) should be placed at both ends of the RS-485 bus. This resistor should be connected between the differential lines (A and B) and should be matched to the characteristic impedance of the cable.
• Can I use the SN75150D for half-duplex communication?
  Yes, the SN75150D can be used for half-duplex communication. In half-duplex mode, the transmitter and receiver are multiplexed onto a single pair of wires, and the device can be switched between transmit and receive modes using the DE (driver enable) and RE (receiver enable) pins.
• What is the minimum input voltage required for the SN75150D to function properly?
  The minimum input voltage required for the SN75150D to function properly is 4.5V. However, it's recommended to operate the device at a voltage between 4.75V and 5.25V for optimal performance.
• How do I handle hot-swapping of devices on the RS-485 bus?
  To handle hot-swapping of devices on the RS-485 bus, it's recommended to use a bus buffer or a repeater that can handle the transient conditions caused by device insertion or removal. Additionally, the device should be designed to withstand the voltage and current transients that occur during hot-swapping.