@@ -117,9 +117,9 @@ One easy way to get power to your project is through USB. It can deliver up to 1
### 9) 3.3v Power Supply
The MCU needs a stable voltage. A common for digital components is 3.3v. To this end we will use a fixed LDO (low dropout) regulator, with a 5v input (powered from the USB connector) and 3.3v output. We will use the (_HA_)
The MCU needs a stable voltage. A common for digital components is 3.3v. To this end we will use a fixed LDO (low dropout) regulator, with a 5v input (powered from the USB connector) and 3.3v output. We will use the [AP2125N-3.3TRG1](https://www.elfa.se/en/ldo-voltage-regulator-3v-360ma-sot-23-diodes-incorporated-ap2125n-3trg1/p/30041163)
Look in the datasheet for reference values for decoupling. Later we will design the power supply for the PWM3389 sensor, which is a bit trickier.
Look in the [datasheet](https://www.elfa.se/Web/Downloads/_t/ds/AP2125_eng_tds.pdf) for a typical application circuit. Later we will design the power supply for the PWM3389 sensor, which is a bit trickier.
### 10) PWM3389DM-T3QU Schematic Symbol
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@@ -141,9 +141,9 @@ Hint. Never, never ever, change the grid settings when placing the pins in the s
As you see in the PWM3389DM-T3QU datasheet and reference schematics, the sensor requires a 1.9v power supply. This is much less common voltage (try finding one from Elfa or rs-online) and you will likely fail.
To that end, you can use an adjustable regulator (_HA_).
To that end, you can use an adjustable voltage regulator, such as [MIC5235YM5-TR](https://www.elfa.se/en/ldo-voltage-regulator-24-20v-sot-23-microchip-mic5235ym5-tr/p/30099685), which will let you set your desired output voltage using external resistors.
The equation for the output voltage can be found in the datasheet for (_HA_).Hint: A good rule of thump is one 100nF ceramic capacitor to each power-pin. Hint2: The smoothing capacitor should be an electrolytic capacitor, hence polarized.
The circuit and equation for calculating the resistor values needed to acheive the desired the output voltage (1.9V) can be found in the [datasheet](https://www.elfa.se/Web/Downloads/_t/ds/MIC5235YM5-TR_eng_tds.pdf) for the regulator. Here you will also find information about input- and output capacitor values needed for proper operation.
Once you have added the 1.9v power supply you can add a new power net, and connect that to your PMW3389 component.
