DAC8775: Act as current source device

Yen Ting Chu

Part Number: DAC8775

Team,

My customer is looking for current source (output) device and I proposed DAC8775 to them. However, it looks like DAC8775 is a bit over spec. My customer is looking for current source device with the below spec:

1. 4mA of output current

2. EN pin controlling, either 4mA or 0mA output

3. Output voltage at 24V

Thanks for your advice.

Best regards,

Andy Chu

over 5 years ago

0 Kevin Duke over 5 years ago

TI__Mastermind 46290 points

Andy,

It would be helpful to understand:

What is the load impedance?
What is the exact output current range desired? 0-4mA? Is it more binary 0mA or 4mA?

Most likely a discrete approach is more appropriate here.

0 Yen Ting Chu over 5 years ago in reply to Kevin Duke

TI__Intellectual 1350 points

Kevin,

1. The max load impedance would be 6k ohm.

2. It is just either 0mA or 4mA. It is not a range.

Best regards,

Andy Chu

0 Yen Ting Chu over 5 years ago in reply to Yen Ting Chu

TI__Intellectual 1350 points

Kevin,

May I have your comment on this? Thanks.

Best regards,

Andy Chu

0 Kevin Duke over 5 years ago in reply to Yen Ting Chu

TI__Mastermind 46290 points

Andy,

Other than specifically having an enable pin to turn this on and off, there is no problem for DAC8775 to drive this load at this current. If a single-pin enable / disable type functionality is really required, a DAC is probably not the right solution. In fact, it is probably an overkill from a performance / capability perspective, meaning there would be an abundance of cheaper solutions.

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DAC8775: Act as current source device