About the built-in voltage regulator max current

Status
Not open for further replies.
F

Fyod

Well-known member
Hi guys,
The Teensy docs warn that the 3.3V output is limited to 250mA.
Looking at the regulator's datasheet, the total output is 1A. Is the 250mA due to a conservative current reserve for the CPU, or a worst case scenario if connected to 500mA capable USB? Thermals? Different reason?
What I'd like to do is safely connect an ESP32. The datasheet mentions various RF modes, one of which is 802.11n, 40 MHz, MCS7, @13 dBm (TX). The peak current there is 260mA. This I think could be mitigated with a ±100uF cap as to not put an unnecessary load and possibly brownout the device.
Is it really stretching it trying to get away with 802.11b, 20 MHz, 1 Mbps, @19.5 dBm, peak 379mA, even if a ±100uF cap is provided?

Cheers!
 
Last edited:
The pinout card guidance is conservative and mostly based on concern over heat dissipation.

Adding a capacitor might help. But taken too far, it might also impact startup behavior by requiring a much larger inrush current to charge the capacitor when powering up, so avoid the temptation (a common misunderstanding, especially among makers and guides published by certain companies) to think that bigger is always better when it comes to power supply capacitors.
 
Status
Not open for further replies.
Back
Top