Maxim > Products > Hot-Swap, PoE, and Power Switching > MAX5942A, MAX5942B

MAX5942A, MAX5942B

IEEE 802.3af Power-Over-Ethernet Interface/PWM Controller for Power Devices

Overview

Technical Documents

Ordering Info

Status

Active: In Production.

Description

The MAX5942A/MAX5942B integrate a complete power IC for powered devices (PD) in a power-over-ethernet (PoE) system. The MAX5942A/MAX5942B provide a PD interface and a compact DC-DC PWM controller suitable for flyback and forward converters in either isolated or nonisolated designs.

The MAX5942A/MAX5942B PD interface complies with the IEEE™ 802.3af standard, providing the PD with a detection signature, a classification signature, and an integrated isolation switch with programmable inrush current control. These devices also feature power-mode undervoltage lockout (UVLO) with wide hysteresis and power-good status outputs.

The MAX5942A/MAX5942B also integrate all the building blocks necessary for implementing DC-DC fixed-frequency isolated power supplies. This device is a current-mode controller with an integrated high startup circuit suitable for isolated telecom/industrial voltage range power supplies. A high-voltage startup circuit allows the PWM controller to draw power directly from the 18V to 67V input supply during startup. The switching frequency is internally trimmed to 275kHz ±10%, thus reducing magnetics and filter components. The MAX5942A allows an 85% operating duty cycle and can be used to implement flyback converters. The MAX5942B limits the operating duty cycle to less than 50% and can be used in single-ended forward converters. The MAX5942A/MAX5942B are designed to work with or without an external diode bridge in front of the PD.

The MAX5942A/MAX5942B are available in 16-pin SO packages.

Data Sheet

Download	Rev 2	(PDF, 460kB)
E-Mail

Key Features

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 FET
- Programmable Inrush Current Control/ULVO
- PGOOD/Active-Low PGOOD Outputs Enable PWM Controller
PWM Controller
- Wide Input Range: 18V to 67V
- Isolated (Without Optocoupler) or Nonisolated Power Supply
- Current-Mode Control
- Leading-Edge Blanking
- Internally Trimmed 275kHz ±10% Oscillator
- Soft-Start

Applications/Uses

Computer Telephony
Internet Appliances
IP Phones
Power Devices in Power-Over-Ethernet/Power-Over-MDI
Security Cameras
Wireless Access Nodes

Key Specifications:

Powered Devices

Part Number

IEEE Compliance

R_DS(ON)
(Ω)

PWM

f_S
(kHz)

Protection Features

Prog. UVLO

Package/Pins

Smallest Available Pckg.
(mm²)

Oper. Temp.
(°C)

Budgetary Price

PD MOSFET

max w/pins

See Notes

MAX5942

802.3af

0.6

Yes

275

Programmable Inrush Current

Yes

SOIC(N)/16

-40 to +85

$2.89 @1k

See All Powered Devices (9)

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Diagram

Typical Operating Circuit

Application Notes

Application Note 3363		New Ethernet Systems Distribute DC Power with Data
Tutorial 4678		Advantages of Internet Protocol (IP) Cameras and H.264 Compression for Security and Surveillance Video

Reliability Reports

Show FIT data for:
Request Reliability Report for:

Software/Models

MAX5942 Macromodel

MAX5942 Orcad Library

MAX5942TR Test Circuit File

Ordering Information

Filters:

Part Number:

Package:

Temperature:

Tape and Reel

Sample

Part Number	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX5942ACSE			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M-6*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX5942ACSE+			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M+6*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5942ACSE+T			Active	N.SO;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX5942ACSE-T			Active	N.SO;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX5942AESE			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M-6*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX5942AESE+			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M+6*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5942AESE+T			Active	N.SO;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX5942AESE-T			Active	N.SO;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX5942BCSE			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M-6*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX5942BCSE+			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M+6*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
Part Number	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX5942BCSE+T			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M+6*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5942BCSE-T			Active	N.SO;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX5942BESE			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M-6*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX5942BESE+			Active	SOIC(N);16 pin;62 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0097 (PDF) Use pkgcode/variation: S16M+6*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX5942BESE+T			Active	N.SO;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX5942BESE-T			Active	N.SO;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet

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; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product 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.

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Information Index

Overview		Technical Documents		Ordering Info		Related Products
Description Key Features Applications/Uses Key Specifications Diagram Notes and Comments		Data Sheet Application Notes Evaluation Kits Product Guides Reliability Reports Software/Models		Price and Availability Samples Buy Online Package Information Lead-Free Information		Similar Products by Function Similar Products by Application Evaluation Kits Products with Similar Part Numbers Products Used With This

Document Ref.: 19-3024 Rev 2; 2004-09-22
This page last modified: 2007-11-13