I'm running a Teensy 4.1 with a 3.5" Estardyn screen running off the T4.1 3.3v. When I measure the screen on the bench I can tell that the BL is driving from the 3.3V VCC and the BL pin is just an enable input. I measure about 58-60mA for the backlight at 3.3v.
I also have a couple of GPS modules and an RS485-UART converter on the T4.1 3.3v. I haven't measured the full load yet but am budgeting about 55mA per GPS module at acquisition at max, and about 35mA for the 485 transmitting (and nominal when idle).
This gives me an external 3.3v load of (worst case) about 205mA although I would never expect to see more than about 160mA sustained.
My question is: Where does the 250mA recommended limit come from? The part is a 1A part I think - so presumably either it's thermal, or a big reservation for the T4.1 itself.
YES YES YES I could put another external regulator on the board, but if the 250mA is a conservative number, accounting for the T4.1's own draw, and already giving good thermal headroom - am I safe running my 160mA with possible very transient peaks of around 200?
Cheers - Neil G
I also have a couple of GPS modules and an RS485-UART converter on the T4.1 3.3v. I haven't measured the full load yet but am budgeting about 55mA per GPS module at acquisition at max, and about 35mA for the 485 transmitting (and nominal when idle).
This gives me an external 3.3v load of (worst case) about 205mA although I would never expect to see more than about 160mA sustained.
My question is: Where does the 250mA recommended limit come from? The part is a 1A part I think - so presumably either it's thermal, or a big reservation for the T4.1 itself.
YES YES YES I could put another external regulator on the board, but if the 250mA is a conservative number, accounting for the T4.1's own draw, and already giving good thermal headroom - am I safe running my 160mA with possible very transient peaks of around 200?
Cheers - Neil G
