DAC7574: RDAC CALCULATION

SATHYA SHREE S

Part Number: DAC7574

Hi,

We are using DAC7574 for voltage margining RAA2142504GSP#HA0. Kindly help us to calculate the RDAC value in Voltage DAC. What value needs to be used for VDAC and RSET.

over 1 year ago

0 Katlynne Jones over 1 year ago

TI__Mastermind 34198 points

Hello,

I would need more details to help support this request. What is the desired output range of the RAA2142504GSP#HA0? Do you already have resistors selected for R1 & R2? Is the below figure a good representation on how you plan to connect the DAC to the circuit?

Best,

Katlynne Jones

0 SATHYA SHREE S over 1 year ago in reply to Katlynne Jones

Intellectual 560 points

Hi Jones,

Desired output voltage 3.3V, we have selected resistors R1=97.6K, R2=57.6K. Yes the representation you mentioned is correct. We will be using like this.

We need R3 resistor value for margining the voltage of 10%. Help us to calculate the value.

Thanks,

S Sathya shree

0 Katlynne Jones over 1 year ago in reply to SATHYA SHREE S

TI__Mastermind 34198 points

Hello,

Thanks for the additional information. Based on the RAA2142504GSP#HA0 reference voltage of 1.224V, you can use a R3 resistor of 348kΩ with a VDAC,low of 47mV (DAC code 0x5) and VDAC, high of 2.4V (DAC code 0xFDC0) to margin by 10%. VDAC,low corresponds to a 3.63V output and VDAC,high corresponds o a 2.97V output.

We do have a calculator tool available on ti.com to help with this calculation.

https://www.ti.com/tool/download/VOLTAGE-MARGINING-CALCULATOR

I'm attaching a version that uses the values you shared. If you need to make any modifications to the resistor values in the future you can check with the calculator tool. SmartDAC-Voltage-Margining-Calculator.xlsx

Best,

Katlynne Jones

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DAC7574: RDAC CALCULATION