TCS37717FN Datasheet, PDF (37/48 Pages) List of Unclassifed Manufacturers – The benefits and features of the TCS3771 are listed below

TCS3771 − Application Information
Application Information
LED Driver Pin with Proximity Detection
In a proximity sensing system, the IR LED can be pulsed by the
TCS3771 with more than 100mA of rapidly switching current,
therefore, a few design considerations must be kept in mind to
get the best performance. The key goal is to reduce the power
supply noise coupled back into the device during the LED
pulses.
The first recommendation is to use two power supplies; one for
the device V_DD and the other for the IR LED. In many systems,
there is a quiet analog supply and a noisy digital supply. By
connecting the quiet supply to the V_DD pin and the noisy supply
to the LED, the key goal can be meet. Place a 1μF low-ESR
decoupling capacitor as close as possible to the V_DD pin and
another at the LED anode, and a 22μF capacitor at the output
of the LED voltage regulator to supply the 100mA current surge.
Figure 44:
Proximity Sensing Using Separate Power Supplies
If it is not possible to provide two separate power supplies, the
device can be operated from a single supply. A 22Ω resistor in
series with the V_DD supply line and a 1μF low ESR capacitor
effectively filter any power supply noise. The previous capacitor
placement considerations apply.
Figure 45:
Proximity Sensing Using Single Power Supply
ams Datasheet, Confidential
[v1-20] 2014-Aug-06
Page 37
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