Features

 Dual active bridge, hot swap MOSFETand

PoE-PD interface in a system-in-package

 100 V N-ch MOSFETs with 0.2 Ω total path

resistance for each active bridge.

 100 V, 0.1 Ω high-side N-ch hot swap MOSFET

 PoE-PD single-signature interface compliant

with IEEE 802.3bt / at / af

 Supports 4-pair PoE applications

 Supports 12 V auxiliary sources

 Identifies which kind of PSE (standard or

legacy) is connected with and provides

successful IEEE802.3bt / at / af classification

indication as a combination of the T0, T1 and

T2 signals (open drain)

 Smart operational modes

 Programmable classification current with

3.3 ms delay.

 Optional Autoclass feature

 Advanced energy-saving MPS timings

 Two-step hot swap current protection: DC with

1 ms delay and short-circuit with 10 us delay.

 Controlled pre-charge of the output capacitor

 PGD signal (open drain) to enable an external

PWM controller.

 Thermal shutdown protection

Applications

 High power wireless data systems

 Security cameras

 Access points

 Public information displays

 PoE lighting systems

Description

The PM8805 is a system-in-package for smart

power supply of Power over Ethernet (PoE)

Powered Devices (PD) and it is applicable for

power level up to 99.9 W.

It embeds: two active bridges and their driving

circuitry, a charge pump to drive the high-side

MOSFETs, the hot swap MOSFET and the

interface compliant with IEEE 802.3bt.

The device performs the physical layer

classification, providing the indication of

successful PSE type identification. A 4-pair PSE

is identified and the information is available by a

dedicated matrix of Tx signals.

The device works with power either from the

Ethernet cable or from an external power source

such as a wall adapter, with possible prevalence

of the auxiliary source with respect to the PoE.

The PM8805 is suitable to build the interface

section of PoE switch mode power supplies

targeting the highest conversion efficiency. It

provides a PGD signal that can be used to enable

a PWM controller, a DC-DC converter or an LED

driver.