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# DAC53004: Current sink application

Part Number: DAC53004

Dear experts,

We are developing a circuit with a DAC53004 as a current source and voltage margining and scaling. In our circuit, we also need current sinks, 0 to 15 µA. At the beginning of the DAC53004's datasheet, we can read, "The DAC outputs provide a force-sense option for use as a programmable comparator and current sink."

I would like to know whether you have some examples to explain how to use the DAC53004 as current sink? It seems possible but I'm not sure to know how to do it!

Best regards

Antoine

• Hi Antoine,

We have this application circuit that uses the force-sense capability to control an external transistor:

Smart DAC LED Biasing Circuit with Low-Power Sleep Mode

High-Side Current Source LED Biasing Circuit Using Smart DACs

If you only need 0 to 15uA then you can directly use the DAC in current output mode to source/sink up to ±250 μA

Voltage margining and scaling circuit with current output smart DAC

Best,

Katlynne Jones

• Hi Katlynne,

Sorry for the very late answer.

Thank you, I have checked all the links pointed out by you and have a better idea of how to use the DAC53004in a current sink mode.

But, I have another question about the output compliance voltage.

In my application, the maximum allowed voltage at the input pin is 420 mV.

In the datasheet, the Min voltage is 200mv with an output range of 0 µA to 25 µA and 400mv with an output range of -25 µA to 25 µA.

What does that mean? Can I use this DAC for this kind of application? or do I need to add some passive components to set the output compliance voltage?

Best

Antoine

• Hi Antoine,

The compliance voltage is the voltage required from the output to VDD or AGND when the DAC is sourcing/sinking current. The minimum VDD supply of 1.8V will ensure you're meeting the compliance voltage to VDD (VDD is at least 420mV + 400mV). The DAC output needs to be at least 400mV (AGND + 400mV) to be able to sink the current. You can add a series resistor to manipulate the voltage seen at the DAC output if necessary.

Best,

Katlynne Jones