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queries about afe 4400

sundar singh pothula
Prodigy 10 points
Other Parts Discussed in Thread: AFE4400

HI

I am working with afe4400, I have some doubts about afe4400

1. Do AFE4400  have any internal filters, if it does how modify the frequency limits.Do I have to design and write a code for  the digital filter in micro controller. 

2. Can i connect the Led/photo diode directly to AFE4400 or I need to connect through H Bridge,

3. IF I am using a Diode H Bridge do i need to provide any external LED drive supply.

  • 0
    TI__Intellectual 1910 points

    Hi Sundar,

    1. Yes, the AFE4400 does have an internal filter as shown in figure 26 of the user's guide (http://www.ti.com/lit/ug/slau480c/slau480c.pdf). The corner can be set to 500 or 1,000 Hz. You can also implement an additional digital filter, but this is not necessary.

    2. The H-Bridge FETs and driver are internal to the device as shown in figure 71 of the datasheet (http://www.ti.com/lit/ds/symlink/afe4490.pdf). You may connect the LED's directly to the TXN and TXP pins as shown in figure 71 or 72 of the datasheet directly to the AFE4400. The photodiode is connected directly to the INN and INP pins as shown in figure 53 of the datasheet. Take note that Cpd is the differential capacitance of the photodiode and not an external capacitor.

    3. The H-Bridge is internal to the device, as is the H-Bridge driver. You will need to provide voltages to the RX_ANA_SUP, RX_DIG_SUP, TX_CTRL_SUP, and LED_DRV_SUP pins. You can find more information about the supplies in the datasheet.

    Regards,

    Gui