AD9674 TGC Gain input driver

Hi,

For AD9674, we need a differential driver for Gain+-, in datasheet figure38, there is reference design, but this design need an input from -1.6V to 1.6V, except a DAC, we need an OP amplifier to convert to bipolar output. and for this amplifier, need a negative power supply.

So I want to know is, is there a more simplified driver? Googled and found Linear has a design(dn454fa), can we use this design? for this design, Can we use op like AD8138? Is there any DAC recommend for this design? Thanks!

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  • 0
    •  Analog Employees 
    on Dec 12, 2017 8:14 AM

    Hi Gsing,

    With the negative power supply, the circuit is easy, and the ADA4938 is the right part. Using the circuits in the CN0181 and ADA4938 is ok for your design, but I do not think the ADA8657 is good candidate due to bigger noise and small GBP. I will recommed you to use ADA4896-2.

    With the single power supply, The AD5429 has 2 channels of current output, you can set different codes to output two complementary output voltages (one is -1.6V to 0 and the other is 0 to -1.6V), and then you can connect these two output to the ADA4940, so you get a true differential circuits. You can use both the AC coupled and DC coupled for the ADA4940 input.  

    AD5450 is a single channel DAC, so it can only support a single end to differential output with the circuit I answered last time.

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  • 0
    •  Analog Employees 
    on Dec 12, 2017 8:14 AM

    Hi Gsing,

    With the negative power supply, the circuit is easy, and the ADA4938 is the right part. Using the circuits in the CN0181 and ADA4938 is ok for your design, but I do not think the ADA8657 is good candidate due to bigger noise and small GBP. I will recommed you to use ADA4896-2.

    With the single power supply, The AD5429 has 2 channels of current output, you can set different codes to output two complementary output voltages (one is -1.6V to 0 and the other is 0 to -1.6V), and then you can connect these two output to the ADA4940, so you get a true differential circuits. You can use both the AC coupled and DC coupled for the ADA4940 input.  

    AD5450 is a single channel DAC, so it can only support a single end to differential output with the circuit I answered last time.

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