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Question regarding from VBATT to 5v on the fly for transmission

Category: Hardware
Product Number: MAX3471

Hello,

We are planning on using the MAX3471 with a dual-voltage configuration.

We will use an ideal ORing diode power muxer to supply voltage directly from VBATT or from a switched 5V rail. This is so we can transmit at a higher 5V level, but maintain low power consumption while being able to receive at all times.

Is there any potential side effects from this power configuration? Are there any slew rate issues with a configuration like

  • I assume VBATT is the battery voltage, and it will be >2.5V so if the 5V rail or battery is powering the chip it meets min and max Vcc conditions. This device has a low data rate and include filtering and hysteresis at the receiver and the driver is already slew rate limited so it should be ok. How many nodes do you have on this bus and do you use any termination?

  • We typically only use a single device with no termination, cable length is 1M.

    This is part of our communication standard that will be able to support up to 10 devices on the same RS485 line, we were planning on implementing AC termination to reduce power losses.

    Baudrate is 19200