DAC53204: Voltage margin Regarding

Bhuvaneshwari k

Prodigy 40 points

Part Number: DAC53204
Other Parts Discussed in Thread: DAC63204

Tool/software:

Hi,

I'm using this DAC53204(Current output mode) in our design.

1.If I need to margin the voltage with +/-10%, How the manual calculation will be?'

2.If I set DAC code as 9A0 In GUI with Imax (+25uA to -25uA) the voltage changes from nominal 1.8V to plus margin 1.98V? How does it arrive? Give a manual calculation.

Below is the example LDO design ,Give a calculation to margin this 1.1V to +/-10%

Please kindly help me with this query with High priority? Thanks a lot

Thanks,

4 months ago

0 Illia Volkov 4 months ago

TI__Intellectual 1895 points

Dear Bhuvaneshwari,

Thank you very much for reaching out.

When it comes to the controlling the output of this LDO, it has a linear response followed by VOUT_NOMINAL = IREF*RREF, where IREF is 50uA.

If you need to vary the VOUT nominal by +-10% you need to inject additional current into the node which is +-10% of the IREF. In other words, DAC needs either sink -10% of IREF , or source +10% of IREF (+-5uA) provided you use 22k RREF.

According to the eq 4 of https://www.ti.com/lit/an/slaae23a/slaae23a.pdf Margin high code = (5uA+25uA)/50uA*256 = 154d Margin low code = 102d

Please take a closer look at the application section of the datasheet of the LDO ( page 67 ) as it goes into more detail on how to use DAC53204/DAC63204 for this application.

https://www.ti.com/lit/ds/symlink/tps7a57.pdf

Thank you very much,

Illia Volkov

0 Bhuvaneshwari k 4 months ago in reply to Illia Volkov

Prodigy 40 points

Hi Illia ,

Thank you so much for your reply,

What if in the above case(schematic)? I have used this LDO in my design.

Thanks and regards,

Bhuvaneshwari

0 Illia Volkov 3 months ago in reply to Bhuvaneshwari k

TI__Intellectual 1895 points

Dear Bhuvaneshwari,

Thank you for your question.

Did you have a second to take a look at the application note I attached ( https://www.ti.com/lit/an/slaae23a/slaae23a.pdf) ? The application note goes step by step on how to calculate the code and resistors and the derevation process. Please note that looks like VFB in the case of this LDO is 200mV.

We also provide this excel based calculator tool that will calculate DAC values/codes (https://www.ti.com/tool/download/VOLTAGE-MARGINING-CALCULATOR).

Please let me know if you have any additional questions.

Thank you,

Illia Volkov

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DAC53204: Voltage margin Regarding