MAX5986A

PRODUCTION

IEEE 802.3af-Compliant, High-Efficiency, Class 1/Class 2, Powered Devices with Integrated DC-DC Converter

Highly Integrated Powered Devices Reduce BOM Cost and Improve Efficiency

Data Sheet (Rev. 7) Product Selection Table

Part Models: 2
1ku List Price: Starting From $4.47

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Overview

High Integration Saves Space and BOM Cost
- Efficient, Integrated DC-DC Converter (with Integrated Switches)
- Built-In Output-Voltage Monitoring
- Protects Against Overload, Output Short Circuit, Output Overvoltage, and Overtemperature
- Integrated TVS Diode Withstands Cable Discharge Event (CDE)
- Internal LDO Regulator with Up to 100mA Load (MAX5987A)
IEEE 802.3af-Compliant Features Reduce Design Time
- PoE Class 1/Class 2 Classification Set with Single Resistor
- Intelligent Maintain Power Signature (MPS) Complies with IEEE 802.3af Specification
- Simplified Wall Adapter Interface
- Pass 2kV, 200m CAT-6 Cable Discharge Event
High Efficiency During Light Loads Reduces Power Consumption
- Sleep and Ultra-Low-Power Mode (MAX5986A/MAX5986B/MAX5986C)
- Frequency Foldback for High-Efficiency Light-Load Operation
- Back-Bias Capability to Optimize the Efficiency
Robust Performance
- 8.7V to 60V Wide Input Voltage Range
- Hiccup-Mode Runaway Current Limit
- 49mA (typ) Inrush Current Limit
- Open-Drain (Active-Low RESET) Output (MAX5987A)
Flexible and Easy to Design With
- 3.0V to 14V Programmable Output Voltage Range
- Internal Compensation
- Fixed 215kHz/430kHz Switching Frequency
- Fixed 3.3V or Adjustable Output Voltage through an External Resistive Divider

The MAX5986A–MAX5986C/MAX5987A provide a complete power-supply solution as IEEE^® 802.3af-compliant Class 1/Class 2 Powered Devices (PDs) in a Power-over-Ethernet (PoE) system. The devices integrate the PD interface with an efficient DC-DC converter, offering a low external part count PD solution. The MAX5987A includes a low-dropout regulator and the MAX5986A–MAX5986C include sleep and ultra-low power modes.

The PD interface provides a detection signature and a Class 1/Class 2 classification signature with a single external resistor. The PD interface also provides an isolation power MOSFET, a 60mA (max) inrush current limit, and a 323mA operating current limit.

The integrated step-down DC-DC converter uses a peak current-mode control scheme and provides an easy-to-implement architecture with a fast transient response. The step-down converter operates in a wide input voltage range from 8.7V to 60V and supports up to 6.49W of input power. The MAX5986A/MAX5986B/MAX5987A operate at a fixed 215kHz switching frequency and the MAX5986C operates at a fixed 430kHz switching frequency. The DC-DC converter operates at a fixed switching frequency, with an efficiency-boosting frequency foldback that reduces the switching frequency by half at light loads.

The devices feature an input undervoltage-lockout (UVLO) with wide hysteresis and long deglitch time to compensate for twisted-pair cable resistive drop and to assure glitch-free transition during power-on/-off conditions. The devices also feature overtemperature shutdown, short-circuit protection, output overvoltage protection, and hiccup current limit for enhanced performance and reliability.

The MAX5986A–MAX5986C/MAX5987A are available in a 16-pin, 5mm x 5mm, TQFN power package and operate over the -40°C to +85°C temperature range.

Applications

IEEE 802.3af-Powered Devices
IP Phones
IP Security Cameras
WiMAX® Base Stations
Wireless Access Nodes

Part Models: 2
1ku List Price: Starting From $4.47

Documentation

Data Sheet 1

MAX5986A-MAX5987A: IEEE 802.3af-Compliant, High-Efficiency, Class 1/Class 2, Powered Devices with Integrated DC-DC Converter Data Sheet (Rev.7) 01/08/2019

Reliability Data 1

MAX5986A Reliability Data 01/12/2023

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
MAX5986AETE+	Thin Quad Flatpack, No Leads	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
MAX5986AETE+T	Thin Quad Flatpack, No Leads	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Sep 18, 2020 - 2054 ASSEMBLY
		pcn_2054
MAX5986AETE+	PRODUCTION
MAX5986AETE+T	PRODUCTION
Mar 16, 2018 - 1719B WAFER FAB
		pcn_1719b
MAX5986AETE+	PRODUCTION
MAX5986AETE+T	PRODUCTION
Jun 20, 2016 - 1612 ASSEMBLY
		pcn_1612
MAX5986AETE+	PRODUCTION
MAX5986AETE+T	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Evaluation Kits

Evaluation Kit for the MAX5986A

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Features and Benefits

IEEE 802.3af/at-Compliant PD Interface Circuit
PoE Classification 1
-36V to -57V Input Range
Demonstrates an Integrated 3.84W Step-Down DC-DC Converter
+5V Output at 768mA
Inrush Current Limit of 49mA (typ)
Evaluates Endspan and Midspan Ethernet Systems
Simplified Wall Adapter Interface
Proven PCB Layout
Fully Assembled and Tested

Product Details

The MAX5986A evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board featuring an Ethernet port, network powered-device (PD) interface controller circuit for -57V supply rail systems. The EV kit uses the MAX5986A IEEE® 802.3af/at-compliant network PD interface controller in a 16-pin TQFN package with an exposed pad. The IC is used in Power-over-LAN (PoL) applications requiring DC power from an Ethernet network port for PDs such as IP phones, wireless access nodes, and security cameras.

The EV kit receives power from IEEE 802.3af/at-compliant power-sourcing equipment (PSE). Refer to the MAX5952, MAX5965A/MAX5965B, and MAX5980 IC data sheets for PSE controllers. The PSE provides the required -36V to -57V DC power over an unshielded twisted-pair Ethernet network cable to the EV kit’s RJ45 magnetic jack. The EV kit features a 1 x 1 Gigabit RJ45 magnetic jack and two active full-wave rectifiers (N101 and N102) for separating the DC power provided by an endspan or midspan Ethernet system.

The EV kit can also be powered by a wall adapter power source. The EV kit provides PCB pads to accept the output of a wall adapter power source. When a wall adapter power source is detected, it always takes precedence over the PSE source and allows the wall adapter to power the EV kit.

The EV kit demonstrates the full functionality of the IC, such as PD detection signature, PD classification signature, inrush current control, input undervoltage lockout (UVLO), and an integrated DC-DC step-down converter. The integrated step-down converter operates at a fixed 275kHz switching frequency, and is configured for a nonisolated +5V DC output that can deliver 768mA of current.

Warning: The EV kit is designed to operate with high voltages. Dangerous voltages are present on this EV kit and on equipment connected to it. Users who power up this EV kit or power the sources connected to it must be careful to follow safety procedures appropriately to work with high-voltage electrical equipment.

Under severe fault or failure conditions, this EV kit may dissipate large amounts of power, which could result in the mechanical ejection of a component or of component debris at high velocity. Operate this kit with care to avoid possible personal injury.