STMicroelectronics PM8803TR

Overview

PM8803TR from STMicroelectronics is a high-efficiency, IEEE 802.3at-compliant integrated PoE-PD interface and current-mode PWM controller in HTSSOP20 package. It integrates a 100 V/0.45 Ω hot-swap MOSFET, programmable DC current limit up to 1 A, and supports flyback, forward, and forward active clamp topologies. It enables seamless dual-source power priority (PoE or auxiliary wall adapter) in VoIP phones and security cameras.

For engineers reviewing the PM8803TR datasheet, PM8803TR pinout, PM8803TR application, or PM8803TR equivalent, key selection considerations include IEEE 802.3at Layer 1 classification indication (T2P signal), inrush current control (140 mA typ.), dual gate drivers (GAT1/GAT2, 1 A peak), oscillator frequency programmability (100–1000 kHz), and thermal shutdown at 160 °C.

Technical Context

The PM8803TR implements hardware-based IEEE 802.3at detection, classification, and undervoltage lockout with dedicated pins (DET, CLS, DCCL) and a successful 2-event classification indicator (T2P). Its PoE interface includes an integrated 100 V hot-swap MOSFET and accurate inrush limiting (140 mA typ.) with automatic switchover to DC current mode at V_DS = 1.5 V.

The PWM controller features current-mode operation with programmable oscillator (via FRS pin), adjustable slope compensation, dual complementary low-side drivers (GAT1/GAT2), and programmable dead time (via DT pin). It supports synchronous rectification and active clamp topologies with 80% max duty cycle and internal temperature sensing.

Key Specifications

Pinout & Package

PM8803TR is housed in a thermally enhanced HTSSOP20 package with exposed pad (EP) for PCB copper plane connection to VSS, supporting ≤40 °C/W junction-to-ambient thermal resistance on a 4-layer board with 6–8 vias.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PoE-PD interface and PWM controller applications.

Compared with MAX5969B and NCP1094, the PM8803TR uniquely combines IEEE 802.3at hardware classification indication (T2P), integrated dual gate drivers, and configurable auxiliary priority - making it optimal for PoE+ powered devices requiring robust dual-source operation without added ICs or digital overhead.

Availability

PM8803TR is available at Aetrix Electronics and suitable for VoIP phones, security cameras, WLAN access points, and industrial PoE+ appliances requiring stable component supply, long-term lifecycle support, and consistent HTSSOP20 tape-and-reel packaging.

Supply support for PM8803TR 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 specializing in power management, analog, and microcontroller solutions for industrial, automotive, and communications markets.

The PM8803TR belongs to ST's Power over Ethernet product line, designed specifically to integrate PoE-PD interface and SMPS control into a single IC for compact, high-efficiency powered devices compliant with IEEE 802.3at.

FAQ

What is the function of the T2P pin on the PM8803TR?

The T2P pin is an open-drain active-low indicator that asserts when the PM8803TR successfully completes IEEE 802.3at two-event classification with a compatible PSE. It is not used for detection or classification itself but provides hardware-level confirmation of Type 2 PSE recognition, enabling system firmware to enable full-power operation only after valid handshake completion.

Can the PM8803TR operate with only an auxiliary power source and no PoE connection?

Yes - the PM8803TR supports auxiliary-only operation via SP or SA pins. Pulling SA high (with voltage divider to ARTN) grants highest priority to the auxiliary source, disabling PoE interface functions while enabling full PWM controller operation. The device draws bias from VC or VB rails and maintains all SMPS control features without Ethernet connection.

How is the DC current limit configured, and what is its maximum value?

The DC current limit is set by a resistor between DCCL pin and VSS. With R_DCCL = 30 kΩ, limit is ~1 A; with R_DCCL = 150 kΩ, limit drops to ~140 mA. The specification guarantees ±15% accuracy across this range. Leaving DCCL open configures default 640 mA limit for standard IEEE 802.3at compliance.

What thermal design guidance applies to the HTSSOP20 package?

The HTSSOP20 package requires connection of the exposed pad (EP) to a PCB copper plane tied to VSS, with 6–8 thermal vias to inner ground/power planes. On a 4-layer board with 35 µm copper, this achieves ≤40 °C/W R_THJA. Layout must separate RTN1, RTN2, and ARTN grounds to prevent switching noise from corrupting current sense signals.