9.3.1 Modes

The R_S, pin 8 of the SN55HVD233-SEP, provides for three modes of operation: high-speed, slope control, or low-power standby mode. The user selects the high-speed mode of operation by connecting pin 8 directly to ground, allowing the driver output transistors to switch on and off as fast as possible with no limitation on the rise and fall slope. The user can adjust the rise and fall slope by connecting a resistor to ground at pin 8, because the slope is proportional to the pin's output current. Slope control is implemented with a resistor value of 0 Ω to achieve a single ended slew rate of approximately 38-V/µs, and up to a value of 50 kΩ to achieve approximately 4-V/µs slew rate. For more information about slope control, refer to Application and Implementation section.

The SN55HVD233-SEP enters a low-current standby (listen-only) mode during which the driver is switched off and the receiver remains active if a high logic level is applied to pin 8. The local protocol controller reverses this low-current standby mode when it needs to transmit to the bus.