What happens if I operate a RS-485 circuit with a 10% supply instead of the recommended 5%?
Generally speaking, the addition or subtraction of 0.25V at the supply will not cause application problems. Parametric sensitivity to the supply voltage will vary with circuit design but, you could expect a direct variation of the output signal level since the high-level output is connected to VCC through a transistor. The other key circuit parameters that could reveal a marginal system design are the receiver input sensitivity and propagation delay times. Although our circuits are not characterized with a 10% VCC, functionality can be assumed. If the system design is near the limits of data rate or line length for RS-485, a laboratory evaluation is recommended.
