Wouter,
   I considered the diode solution but that adds 500mV to the Vol/Voh,=20
so I was hoping that there exists someplace the ideal solution.
-Phil-

On 12/17/2014 11:55 AM, Wouter van Ooijen wrote:
> 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
> 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
> (but that has a SR input, not a parallel input).
>
> Wouter van Ooijen

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