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LMX8410L: Using separate regulators to split Vcc current

Part Number: LMX8410L

I want to use different lower noise regulators for the Vcc supply than what is used on the eval card. The data sheet only gives the total current for the 3.3V supplies, says it needs 650mA typical while another place says the supply should be able to source 800mA. I want to separate these Vcc (3.3V) inputs and run them off of two separate 500mA regulators. Is there data available for the current draw of each of the 3.3V inputs? Also, is there an optimum way of doing this, of grouping the inputs into two groups? Which are digital, analog, most sensitive to interference?

My choices are, I can use two regulators and split the Vcc into two groups or I can parallel the two regulator outputs and run all the Vcc's together. Which is the best way?

The Vcc supply inputs are:

Vcc_RFI, Vcc_IFI, Vcc_RFQ, Vcc_IFQ, Vcc_Buf, Vcc_Dig, Vcc_CP, Vcc_MASH, Vcc_VCO

  • Charles,

    The 3.3V rail draws about 650mA and the 5V rail draws about 140mA. You can decide for yourself how much margin you need, but the datasheet recommends 800mA and 200mA, respectively.

    I'm afraid that we do not have data for the current consumption of each power pin, so I'm not able to recommend how to group the power inputs. Please refer to datasheet section 9: Power Supply Recommendations for design information.