Analog Devices Inc./Maxim Integrated MAX5969AETB+T

Overview

MAX5969AETB+T from Maxim Integrated is an IEEE 802.3af/at-compliant powered device (PD) interface controller with integrated n-channel isolation MOSFET, designed for PoE-powered endpoints. It delivers detection signature (24.9kΩ), 2-event classification (Class 0–5), inrush current limiting (≤180mA), and 720–880mA operating current limit, enabling robust power handshaking in IP phones, security cameras, and wireless access nodes.

For engineers reviewing the MAX5969AETB+T datasheet, MAX5969AETB+T pinout, MAX5969AETB+T application, or MAX5969AETB+T equivalent, key selection criteria include UVLO threshold (35.4V turn-on), TDFN-EP package thermal performance (θJA = 4°C/W), wall adapter switchover support, and 100V absolute maximum input rating - all critical for PoE PD design validation and BOM consolidation.

Technical Context

The MAX5969AETB+T implements a dual-mode UVLO (35.4V turn-on / 31V turn-off with 4.2V hysteresis) and supports IEEE 802.3at 2-event classification via CLS resistor programming and 2EC latched output. Its internal isolation MOSFET features 0.5–1.0Ω on-resistance (depending on junction temperature) and integrates di/dt control to manage inrush transients.

Operation spans four voltage-defined modes: detection (1.4–10.1V), classification (12.6–20V), mark event (10.1–12.6V falling), and power mode (>35.4V). The device asserts PG (open-drain, 375µA sink capability) for downstream DC-DC enable sequencing and uses WAD-to-RTN voltage sensing (>9V) to trigger seamless wall adapter switchover.

Key Specifications

Pinout & Package

MAX5969AETB+T is housed in a thermally enhanced 10-pin TDFN-EP package (3mm × 3mm) with exposed pad (EP) that must be soldered to a VSS-connected copper plane for optimal thermal performance. The EP is internally connected to VSS through a resistive path and is not electrically isolated.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar powered device interface applications.

Compared with MAX5969BETB+T, the MAX5969AETB+T offers tighter UVLO hysteresis for faster re-engagement after brief dips, while the LT4275AIMSE#PBF demands additional components to replicate wall adapter switchover - making MAX5969AETB+T the optimal choice for cost-sensitive, space-constrained dual-source PoE endpoints.

Availability

MAX5969AETB+T is available at Aetrix Electronics and suitable for IP phones, wireless access nodes, and IP security cameras requiring stable component supply, PoE+ compliance, and auxiliary power arbitration.

Supply support for MAX5969AETB+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) designs precision analog, mixed-signal, and power management ICs for demanding industrial, communications, and computing applications.

The MAX5969A/MAX5969B product line targets IEEE 802.3af/at PoE-powered devices needing integrated power switching, robust classification, and seamless auxiliary source handover - optimized for compact, thermally constrained endpoints.

FAQ

What is the primary function of the MAX5969AETB+T in a PoE system?

The MAX5969AETB+T serves as a complete IEEE 802.3af/at-compliant powered device (PD) interface controller. It performs detection signature generation, 2-event classification, inrush current limiting, and controlled power-up via its integrated isolation MOSFET. In the MAX5969AETB+T, this enables reliable PoE handshaking and power delivery for endpoints like IP phones and security cameras while supporting automatic switchover to wall adapter power.

How does the MAX5969AETB+T handle wall adapter detection and switchover?

The MAX5969AETB+T monitors the WAD pin relative to RTN and asserts the 2EC output when voltage exceeds 9V, triggering immediate shutdown of the isolation MOSFET and enabling auxiliary power path. This switchover is seamless and does not require external logic. The MAX5969AETB+T's WAD detection threshold (9V) and hysteresis (0.725V) ensure noise immunity, and its non-latched 2EC behavior for wall adapter events allows rapid reversion to PoE when auxiliary power is removed.

What are the key differences between MAX5969AETB+T and MAX5969BETB+T?

The MAX5969AETB+T and MAX5969BETB+T share identical pinout, package, and core functionality but differ in UVLO thresholds: MAX5969AETB+T uses 35.4V turn-on / 31V turn-off (4.2V hysteresis), while MAX5969BETB+T uses 38.6V / 31V (7.3V hysteresis). This makes the MAX5969AETB+T more responsive to marginal input conditions, whereas the MAX5969BETB+T provides greater noise margin in long-cable or high-drop installations.

Can the MAX5969AETB+T support IEEE 802.3at Type 2 (PoE+) classification?

Yes, the MAX5969AETB+T fully supports IEEE 802.3at Type 2 classification via its 2-event protocol. It generates the required mark current (IMARK = 0.25–0.85mA) and reset event threshold (2.8–5.2V) to respond to Type 2 PSE probing, and latches the 2EC output upon successful identification. The MAX5969AETB+T's classification current ranges (e.g., 52.7–63.3mA for Class 5) align precisely with IEEE 802.3at tables, enabling up to 25.5W power delivery.

What thermal considerations apply to the MAX5969AETB+T in continuous operation?

The MAX5969AETB+T features a thermally enhanced 10-pin TDFN-EP package with θ_JA = 4°C/W and θ_JC = 9°C/W. Its thermal shutdown activates at +140°C with +28°C hysteresis, and the exposed pad must be soldered to a VSS-connected copper plane. Under 800mA load at +85°C ambient, the MAX5969AETB+T's 1.0Ω max R_ON yields ~640mW conduction loss - requiring ≥4cm² of 2oz copper for safe operation without forced air.