Phil Keller schreef op 17-Dec-14 8:34 PM:
> I have a need for a design I am working on for a high current, high
> voltage selectable OPEN-DRAIN or OPEN-SOURCE buffer/driver.
> To be more specific I need:
> * Operate over a Vcc of 5v (or less) to 18v (or more)
> * 5v on the input control, up to 16v on the outputs.
> * Max toggle rate of < 5KHz.
> * Capable of sourcing OR sinking > 100mA continuously
> * Operate as either an OPEN_DRAIN or as an OPEN_SOURCE
> * Not overly cost sensitive.
> * I need a total of 40 per board so up to 8 drivers per package would be =
OK.
>
> My first thought was to use a Tri-State buffer. The data input would
> define which direction would be the driven direction and the enable
> cause the device to go from Hi-Z to active. Thus for an OPEN_DRAIN I
> would have the input LOW (assuming a non-inverting buffer) and connect
> the ENABLE signal to the controlling source. Enable active >> Output
> driven LOW. Enable inactive >> Output OFF.
>
> I have been unable to find a device that meets these requirements. I
> looked at the TI UCC27524 device which has an ENABLE pin. The problem is
> that the ENABLE is actually AND=92d with the input pin, it is NOT
> Tri-State device.

As you explicitly want only sink or on;y source, couldn't you put a=20
diode in series with the output of your favourite non-tristating chip?

My reflex is to check the ULN2803 and relatives. Or maybe the TPIC595=20
(but that has a SR input, not a parallel input).

Wouter van Ooijen
--=20
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