I am connecting this device to a 1.8V UART. I am trying to size a power supply for the 1.8V side of this chip. The UART is powered by an off-board supply.
What will be the maximum current draw from the VL pin?
VCC=5.0V
VL=1.8V
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I am connecting this device to a 1.8V UART. I am trying to size a power supply for the 1.8V side of this chip. The UART is powered by an off-board supply.
What will be the maximum current draw from the VL pin?
VCC=5.0V
VL=1.8V
Hi Jon,
Good question. The VL current is typically small enough to not require any special consideration within a power budget (it is just powering the logic IOs of the chip), but we will see if we can give a more specific answer. We will get back to you later this week.
Max
Jon,
Just to give a quick update - we've had some difficulties getting this test set up this week due to lack of availability of a suitable test PCB. We will keep working to resolve this and update you once we have a clearer answer.
Max
Max,
Thanks for the support. I can verify the final current draw on the design prototype if you can give some general recommendations so you don't have to setup hardware on your end.
My initial guess is that it should only be a few milliamps (probably <5-10mA ish?) including driving the two IO lines. Since this is the only 1.8V component on my PCB, i'll probably just use an LDO or voltage reference to keep the supply simple and pull off the onboard 3.3V rail. I expect to make a second revision before production and will have a chance to optimize this if necessary.
-Jon
Jon,
It should be below 5 mA. VL only powers some low-voltage logic in the IC, nothing more current-hungry like the charge pump, output driver, receiver circuit, etc.
Max