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Powering switched capacitor RS232 devices from separate supply?

Other Parts Discussed in Thread: MAX3243E

Hi, I want to put in about 25 MAX3243E chips in a design, but I don't want to power the RS232 interface by the on-board switched capacitor scheme. Can I attach a separate (central) supply to the +V and -V pins (presumably +6V and -6V DC) and leave out the switched capacitor circuit capacitors? (Obviously, needing a few general bypass caps here and there). Is there an application note for this? I think I saw this suggested somewhere before, but I can't find it. Thank You, Joe Norris

  • Joe,

    You need to make sure that at no time VCC > V+ or V- > GND. Reason: internal diode VCC to V+ and V- to GND
    C1 and C2 pins must be unconnected.

    I am not aware of an application note, but I have used this method internally for MAX3xxx device testing.
    In summary the idea is technically feasible, but I do not have full characterization data to support this.