The maximum cable length depends on the data rate and the type of cable used. As a general rule, the SN75188DE4 can support cable lengths up to 100 meters at a data rate of 1 Mbps. However, it's recommended to consult the TI application note 'TIA/EIA-485 and TIA/EIA-422-B Overview' for more detailed information on cable length and data rate trade-offs.
To ensure reliable operation in noisy environments, it's essential to follow proper PCB layout and design practices, such as using a ground plane, separating analog and digital signals, and using shielding and filtering techniques. Additionally, consider using a common-mode choke or a ferrite bead to reduce electromagnetic interference (EMI).
Yes, the SN75188DE4 can be used in a multi-point configuration, but it's essential to ensure that the total bus loading does not exceed the recommended maximum of 60 units. A unit is defined as a transmitter or receiver, and each device on the bus counts as one unit. Consult the datasheet for more information on bus loading calculations.
The SN75188DE4 can operate from a single 5V supply, with a minimum voltage of 4.5V and a maximum voltage of 5.5V. However, it's recommended to operate the device within the recommended operating range of 4.75V to 5.25V for optimal performance and reliability.
Proper bus termination is critical in RS-485 networks to prevent signal reflections and ensure reliable data transmission. A 120-ohm termination resistor should be connected between the differential lines (A and B) at each end of the bus. Additionally, consider using a biasing network to maintain a stable common-mode voltage.
SN75188DE4 datasheet
by Texas Instruments
