STMicroelectronics EVALPM8803-FWD

Overview

EVALPM8803-FWD from STMicroelectronics is an evaluation board for the PM8803 IEEE 802.3at-compliant PoE-PD interface and current-mode PWM controller, supporting forward active clamp and synchronous flyback topologies. It integrates a 100 V/0.45 Ω hot-swap MOSFET, programmable 100–1000 kHz oscillator, dual gate drivers (GAT1/GAT2), and hardware-based Layer 1 classification for Type 2 PSE detection. Designed for VoIP phones and security cameras powered via Ethernet or auxiliary wall adapters.

For engineers reviewing the EVALPM8803-FWD datasheet, EVALPM8803-FWD pinout, EVALPM8803-FWD application, or EVALPM8803-FWD equivalent, this board enables rapid validation of PoE+ PD power architecture with priority-controlled auxiliary source switchover, inrush/DC current limiting, and thermal shutdown protection under real-world load transients.

Technical Context

The EVALPM8803-FWD implements the full PM8803 reference design for forward active clamp topology, including external components for detection/classification resistors (DET/CLS), DC current limit (DCCL), delay time (DT), and oscillator frequency (FRS). It routes all 20 HTSSOP pins-including separate RTN1, RTN2, and ARTN grounds-to minimize noise coupling between power and analog sections.

Board-level features include dedicated PCB copper planes connected to the exposed pad (EP) for thermal management, resistor-divider networks for SP/SA auxiliary start-up control, and optocoupler biasing circuitry tied to CTL/VB pins. The layout follows ST's guidelines for PoE converter grounding and high-voltage isolation between VDD/VSS and low-side logic.

Key Specifications

Availability

EVALPM8803-FWD is available at Aetrix Electronics and suitable for PoE-powered VoIP phones, IP security cameras, WLAN access points, and WiMAX CPEs requiring stable component supply during prototyping and pre-production validation phases.

Supply support for EVALPM8803-FWD includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power management, analog, microcontrollers, and automotive-grade ICs with ISO 9001 and IATF 16949 certified manufacturing.

The PM8803 product line targets high-efficiency, single-chip PoE-PD solutions for IEEE 802.3at (PoE+) applications where space-constrained designs require integrated hot-swap, classification, and flexible DC-DC control.

FAQ

What topologies does EVALPM8803-FWD support out of the box?

EVALPM8803-FWD is configured and validated for forward active clamp operation per Figure 1 of the PM8803 datasheet. It also supports synchronous flyback (Figure 2) via minor component changes-specifically repositioning the secondary-side MOSFET and adjusting GAT2 timing using the DT resistor. No PCB redesign is required.

How does the board handle auxiliary power source priority switching?

EVALPM8803-FWD implements SA pin biasing to assert high-priority auxiliary mode: when SA voltage exceeds 1.2 V (typ.), the PM8803 disables PoE input and powers up from the wall adapter. SP pin enables low-voltage auxiliary start-up below nominal PoE voltage (≥13 V), with built-in hysteresis to prevent oscillation during transition.

Can EVALPM8803-FWD be used to validate IEEE 802.3bt (PoE++) compliance?

No. EVALPM8803-FWD is designed exclusively for IEEE 802.3at (PoE+) with 30 W maximum input. The PM8803 IC lacks the four-pair detection, higher current classification (Class 5–8), and dual-signature support required for 802.3bt. It does not support autoclass or multi-event classification beyond 2-event Layer 1.

What thermal performance can be expected during full-load operation?

With the EP pad soldered to a 4-layer PCB having ≥6 vias to an internal ground/power plane, EVALPM8803-FWD achieves ≤40 °C/W junction-to-ambient thermal resistance. At 30 W output with 85 °C ambient, measured junction temperature remains below 125 °C-within the PM8803's operational range-when using recommended layout practices from Section 7 of the datasheet.