# TX-SDK-V2 - Ultrasound Demoboard Power-up Questions

Hello,

I am about to power-up the system. I want to make sure everything is correct during this procedure.

I was going to use mechanical switches to connect the bench power supplies on one side and the banana plugs from the board on the other side. I read in another post this could potentially damage the pulser IC, due to voltage spikes and reflection. So, I am going to follow the steps described in page 12 from the PDF "V2 User Guide", connecting the banana plugs directly to the PSUs and powering each one of them in sequence. I have some questions and observations, though.

In the picture depicting the PSUs the 3.3/1.8V rails are generated from a single power supply. The next page states that is necessary to power up the 3.3V rail before the 1.8V one. Does it make a difference to power-up them at the same time/separately? For the symmetric rails I assume I can power-up them at the same time. Therefore, I will follow this power-up sequence:

1. VSUB, the most negative voltage (I will set it to -60V), current limited at 100mA

2. +3.3V/+1.8V, current limited at 100mA

3. +1.8V (in case it is mandatory to power up this rail separately), current limited at 100mA

4. +5V/-5V, current limited at 100mA

5. +10/-10V, current limited at 250mA

6. other +10/-10V, to generate +40V/-40V through the difference from the +50/-50V rails, current limited at 100mA

7.+50/-50V, current limited at 250mA

To power-down I will follow the sequence in the reverse order. GND will be connected all the times. J_SUB in the default “2-3” position. All the outlets in the lab I am working are grounded, so I will make the connections as they are depicted in the figure.

As long as VPF >= VPP - 14 and VNF <= VNN + 14V I assume the device should be protected from damages. Then, the +40/-40V banana plugs will be first connected to +10/-10V voltages in step 6. As soon as I power up the +50/-50V supply it will generate +40/-40V. Is there any condition in which a single +40V/-40V supply is better suited?