POE

Manufacturers

https://silvertel.com/poe-power-over-ethernet-html/	Silvertel	POE modules
https://www.st.com/en/power-management/power-over-ethernet-ics/products.html	ST	POE ic's

Theory

https://www.newnets.ru/knowledge/19942/

IEEE802.3af	up to 13W
IEEE802.3at	up to 30W
IEEE802.3bt	up to 99W

In Power over Ethernet systems, the power sourcing equipment (PSE) senses the Ethernet connection to detect if the powered device (PD) is plugged into the cable termination by applying a small voltage (2.7 V to 10 V) on the Ethernet cable and measures the equivalent resistance in at least two consecutive steps. During this phase, the PD must present a resistance between 23.75 kW and 26.25 kΩ.

Designers can set the current by changing the value of the external resistor according to the following table:

Table 7: Value of the external classification resistor for the different PD classes of power

Class	PD max. average power (W)	RCLS (Ω)
0	13	2k
1	3.84	150
2	6.49	80.6
3	13	51.1
4	25.5	35.6

PSE - power sourcing equipment

PD - powered device

https://www.st.com/en/power-management/pm8800.html	ST	PM8800	ic	IEEE 802.3af	NRND	~5$	https://sds.compel.ru/infosheet/ST/PM8800A
https://www.st.com/en/power-management/pm8803.html	ST	PM8803	ic	IEEE 802.3at
https://www.st.com/en/power-management/pm8804.html	ST	PM8804	ic	~2$	https://sds.compel.ru/infosheet/ST/PM8804TR
https://www.st.com/en/power-management/pm8805.html	ST	PM8805	ic	IEEE 802.3bt	~15$	https://sds.compel.ru/infosheet/ST/PM8805TR
https://www.promelec.ru/fs/sources/83/5a/32/b8/4aa6318fe63f3c434997a44a.pdf	Onsemi	NCP1083DEG	ic	IEEE 802.3bt