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Active: In Production.

Data Sheet

FULL DATA SHEET (PDF, 376kB) Download   E-Mail

Description

The MAX5953A/MAX5953B/MAX5953C/MAX5953D integrate a complete power IC solution for Powered Devices (PD) in a Power-Over-Ethernet (PoE) system, in compliance with the IEEE 802.3af standard. The MAX5953A/MAX5953B/MAX5953C/MAX5953D provide the PD with a detection signature, a classification signature, and an integrated isolation switch with programmable inrush current control. These devices also integrate a voltage-mode PWM controller with two power MOSFETs connected in a two-switch voltage-clamped DC-DC converter configuration. An integrated MOSFET provides PD isolation during detection and classification. All devices guarantee a leakage current offset of less than 10µA during the detection phase. A programmable current limit prevents high inrush current during power-on. The devices feature power-mode undervoltage lockout (UVLO) with wide hysteresis and long deglitch time to compensate for twisted-pair-cable resistive drop and to assure glitch-free transition between detection, classification, and power-on/-off phases. The MAX5953A/MAX5953C have an adjustable UVLO threshold with the default value compliant to the 802.3af standard, while the MAX5953B/MAX5953D have a lower and fixed UVLO threshold compatible with some legacy pre-802.3af power-sourcing equipment (PSE) devices. The DC-DC converters are operable in either forward or flyback configurations with a wide input voltage range from 11V to 76V and up to 15W of output power. The voltage-clamped power topology enables full recovery of stored magnetizing and leakage inductive energy for enhanced efficiency and reliability. When using the high-side MOSFET, the controller can be configured as a buck converter. A look-ahead signal for driving secondary-side synchronous rectifiers can be used to increase efficiency. A wide array of protection features include UVLO, over-temperature shutdown, and short-circuit protection with hiccup current limit for enhanced performance and reliability. Operation up to 500kHz allows for smaller external magnetics and capacitors. The MAX5953A/MAX5953B/MAX5953C/MAX5953D are available in a high-power (2.22W), 7mm x 7mm thermally enhanced thin QFN package.

Key Features		Applications/Uses
Powered Device Interface Fully Integrated IEEE 802.3af-Compliant PD Interface PD Detection and Programmable Classification Signatures Less than 10µA Leakage Current Offset During Detection Integrated MOSFET for Isolation and Inrush Current Limiting Gate Output Allows External Control of the Internal Isolation MOSFET Programmable Inrush Current Control Programmable Undervoltage Lockout (MAX5953A/MAX5953C) DC-DC Converter Clamped, Two-Switch Power IC for High Efficiency Integrated High-Voltage 0.4Ω Power MOSFETs Up to 15W Output Power Bias Voltage Regulator with Automatic High-Voltage Supply Turn-Off 11V to 76V Wide Input Voltage Range Feed-Forward Voltage-Mode Control for Fast Input Transient Rejection Programmable Undervoltage Lockout Overtemperature Shutdown Indefinite Short-Circuit Protection with Programmable Fault Integration Integrated Look-Ahead Signal for Secondary-Side Synchronous Rectification > 90% Efficiency with Synchronous Rectification Up to 500kHz Switching Frequency High-Power (2.22W), 7mm x 7mm Thermally Enhanced Lead-Free Thin QFN Package		Computer Telephony IEEE 802.3af Powered Devices Internet Appliances IP Phones Security Cameras Wireless Access Nodes

Diagram

Typical Operating Circuit

Application Notes

Application Note 3912: Low-Cost, Complete Power Solution for Powered Devices Includes a 12V Buck Converter - MAX5953A, MAX5953B, MAX5953C, MAX5953D

Design Guides

Power Management for Battery-Powered Equipment (PDF)

Reliability Reports

Show FIT data for: MAX5953 Request Reliability Report for: MAX5953A MAX5953B MAX5953C MAX5953D MAX5953

Software/Models

none

Ordering Information

Notes: Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day. Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

Devices: 1-8 of 8

MAX5953A	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX5953AUTM+			Active	TQFN;48 pin;50.4 mm² Outline Drawing: 21-0144 (PDF) Land Pattern: 90-0040 (PDF) Use pkgcode/variation: T4877MN+8*	0°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5953AUTM+T			Active	Land Pattern: Not Available	0°C to +85°C	See data sheet
MAX5953B	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX5953BUTM+			Active	TQFN;48 pin;50.4 mm² Outline Drawing: 21-0144 (PDF) Land Pattern: 90-0040 (PDF) Use pkgcode/variation: T4877MN+8*	0°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5953BUTM+T			Active	Land Pattern: Not Available	0°C to +85°C	See data sheet
MAX5953C	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX5953CUTM+			Active	TQFN;48 pin;50.4 mm² Outline Drawing: 21-0144 (PDF) Land Pattern: 90-0040 (PDF) Use pkgcode/variation: T4877MN+8*	0°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5953CUTM+T			Active	Land Pattern: Not Available	0°C to +85°C	See data sheet
MAX5953D	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX5953DUTM+			Active	TQFN;48 pin;50.4 mm² Outline Drawing: 21-0144 (PDF) Land Pattern: 90-0040 (PDF) Use pkgcode/variation: T4877MN+8*	0°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5953DUTM+T			Active	Land Pattern: Not Available	0°C to +85°C	See data sheet

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New Product Press Release 2006-04-21  Product Ad: Download

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