We initially became interested in the LTC9105 for an ESP32 based industrial monitoring gateway because of its I²C telemetry and PoE power-allocation reporting. However, its datasheet shows a higher-voltage input/AUX architecture that does not appear to directly accommodate a 12 VDC auxiliary source. Is that indeed the case? Alternatively, we reviewed the LTC4278 because its auxiliary input range appears much better suited to a 12 VDC source, although it does not appear to provide the same telemetry capabilities. For our application, we are particularly interested in power telemetry. Ideally, the host processor could determine:
• Whether the active source is PoE+ or external 12 VDC
• Input voltage, current and power consumption
• PoE classification/allocated power, if practical
• Presence/status of the alternate power source
Edit Notes
corrected post[edited by: Rob1887 at 4:56 PM (GMT -4) on 20 Sep 2026]
