Analog Devices Inc./Maxim Integrated MAX5965AUAX+T

Overview

The MAX5965AUAX+T from Maxim Integrated is a quad, monolithic, -48V power-sourcing equipment (PSE) controller compliant with IEEE 802.3af and compatible with IEEE 802.3at. It performs PD detection, classification (including Class 5 and 2-event Class 6), current limiting, and DC/AC load disconnect detection across four independent ports. Designed for midspan injectors and Ethernet switches, it delivers up to 45W per port in high-power mode.

For engineers reviewing the MAX5965AUAX+T datasheet, MAX5965AUAX+T pinout, MAX5965AUAX+T application, or MAX5965AUAX+T equivalent, key selection considerations include its 36-pin SSOP package, I²C-compatible 3-wire interface, programmable startup/fault timeouts, instantaneous per-port current readout, and support for legacy high-capacitance PDs.

Technical Context

The MAX5965AUAX+T implements a fully software-configurable PSE control architecture with four independent port state machines, each managing detection, classification, current foldback, and fault response. Its analog front-end includes precision SENSE_ inputs (±5µA bias), programmable VSENSE_ trip thresholds (e.g., 177–443 mV), and integrated 9-bit ADC for real-time current monitoring.

It supports four operational modes-Auto, Semi-Auto, Manual, and Shutdown-with hardware pins (AUTO, MIDSPAN, SHD1–SHD4) and register-based control. Critical safety functions include input UVLO (28.5V), OVLO (62.5V), thermal shutdown (+150°C), and load-stability checks during detection.

Key Specifications

Pinout & Package

MAX5965AUAX+T is housed in a 36-pin SSOP (Shrink Small Outline Package) with exposed pad for thermal performance. The package measures 12.8 mm × 7.5 mm × 2.2 mm (max height) and is RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PSE controller applications.

Compared with MAX5965AEAX+, the MAX5965AUAX+T trades extended temperature support for lower cost and simplified qualification in commercial environments; compared with MAX5952AESA+, it delivers 3× higher per-port power, real-time current visibility, and future-proof 802.3at compatibility - making it essential for next-generation PoE infrastructure.

Availability

MAX5965AUAX+T is available at Aetrix Electronics and suitable for enterprise switches, midspan power injectors, and industrial routers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for MAX5965AUAX+T 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

Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for communications, computing, and industrial applications.

The MAX5965A/B product line was designed specifically for intelligent, scalable Power over Ethernet infrastructure - targeting PSE equipment that demands high port density, precise current control, and seamless 802.3af/at interoperability.

FAQ

What is the maximum power per port supported by the MAX5965AUAX+T?

The MAX5965AUAX+T supports up to 45W per port in high-power mode, enabling IEEE 802.3at Type 2 compliance. This is achieved through programmable current limits (e.g., VSU_LIM = 170–220 mV) and foldback control, allowing safe delivery to Class 4 and Class 5 powered devices. The MAX5965AUAX+T achieves this without external components beyond the external MOSFET and sense resistor.

Does the MAX5965AUAX+T support AC load disconnect detection?

No, the MAX5965AUAX+T does not support AC load disconnect detection. That feature is exclusive to the MAX5965B variant (e.g., MAX5965BUAX+). The MAX5965AUAX+T is the 'A' version, which omits the OSC input functionality and associated AC detection circuitry. For AC disconnect capability, the MAX5965BUAX+ or MAX5965BEAX+ must be selected instead.

How is port current measured and reported in the MAX5965AUAX+T?

The MAX5965AUAX+T integrates a 9-bit ADC that digitizes the SENSE_ voltage for each port. Current is calculated using the external sense resistor value (e.g., 0.5Ω) and read out instantaneously via the I²C interface - eliminating the need for external ADCs or polling delays. The ADC provides ±5 mV absolute accuracy at 300 mV input, supporting precise real-time power budgeting in the host system.

What are the key differences between MAX5965AUAX+T and MAX5952AESA+?

The MAX5965AUAX+T offers significantly enhanced capabilities over the MAX5952AESA+, including 45W vs. 15.4W per port, Class 5/6 classification, I²C-based instantaneous current readout, programmable safety timers, and high-capacitance PD detection. While pin-compatible, the MAX5965AUAX+T requires no firmware changes to upgrade existing MAX5952 designs - delivering immediate power and intelligence gains.

Can the MAX5965AUAX+T operate in both endpoint and midspan PSE configurations?

Yes, the MAX5965AUAX+T supports both configurations via the MIDSPAN pin. When MIDSPAN is pulled low (default via internal 50kΩ pulldown), it operates as an endpoint PSE (powering over data pairs). When driven high to VDD, it configures for midspan operation (powering over spare pairs). This dual-mode flexibility allows one design to serve switch-integrated and standalone injector applications.