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SYSTEM BOARD 6702

MAXREFDES1177: POE POWERED DEVICE AND 12V/600mA NO-OPTO FLYBACK DC-DC CONVERTER USING THE MAX17690 AND MAX5969B


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Overview


Designed, Built, Tested

The Reference Design Document describes the hardware pictured below. It provides a detailed systematic technical guide to designing a PoE powered device and 12V/600mA No-Opto flyback DC-DC converter using the MAX17690 and MAX5969B. The hardware was built according to the linked Schematic, Bill of Materials and PCB Artwork. It was tested by Maxim’s expert applications engineering team in a state-of-the-art design lab and the Test Results are fully documented. Functionality of the design over all electrical operating conditions was verified with the MAXREFDES1177 Simulation Circuit using Maxim’s OASIS Circuit Simulation Tool. Downloadable ECAD/EDA files are available in 7 different formats including OrCAD, Altium, Mentor DX Designer, Eagle and more.

Description

Input Type VIN (MIN)
(V)		 VIN (MAX)
(V)		 IOUT
(A)		 Single/Multiple
Output		 VOUT
(V)		 POUT
(W)		 Isolated/Non-Isolated Topology
DC 30 60 0.6 Single 12 7.2 Isolated Flyback

Power over Ethernet (PoE) is a technology that allows network cables to deliver power to a powered device (PD) through power-sourcing equipment (PSE) or midspan, and has many advantages over traditional methods of delivering power. PoE allows power and data to be combined, removing the need for altering the AC mains infrastructure and can be installed by non-electricians. PoE is an intelligent system designed with protection at the forefront, preventing overload, underpowering, and installation errors, while allowing simple scalability and reliability.

The MAX17690 implements an innovative algorithm to accurately determine the output voltage by sensing the reflected voltage across the primary winding during the flyback time interval. By sampling and regulating this reflected voltage when the secondary current is close to zero, the effects of secondary-side DC losses in the transformer winding, the PCB tracks, and the rectifying diode on output voltage regulation can be minimized. The MAX17690 also compensates for the negative temperature coefficient of the rectifying diode.

Key Features

  • IEEE 802.3af/at Compliance
  • Thermally Enhanced, 3mm × 3mm, 10-Pin TDFN Package (MAX5969B)
  • 30V to 60V Input Voltage Range
  • Programmable Switching Frequency from 50kHz to 250kHz
  • Programmable Input Enable/UVLO Feature
  • Programmable Input Overvoltage Protection
  • Adjustable Soft-Start
  • 2A/4A Peak Source/Sink Gate Drive Capability
  • Hiccup Mode Short-Circuit Protection
  • Fast Cycle-by-Cycle Peak Current Limit
  • Thermal Shutdown Protection
  • Space-Saving, 16-Pin, 3mm × 3mm TQFN Package
  • -40°C to +125°C Operating Temperature Range
MAXREFDES1177 Hardware Enlarge+


This board is not available for purchase.

Design Resources


Schematic

Tools & Models

PCB Layout

Test Results

View PDF

Bill of Material

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Reference Design Document

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Parts Used

MAX17690
60V, No-Opto Isolated Flyback Controller

  • 4.5V to 60V Input Voltage Range
  • No Optocoupler or Third Winding Required to Derive Feedback Signal Across Isolation Boundary
  • 2A/4A Peak Source/Sink Gate Drive Currents

MAX5969B
IEEE 802.3af/at-Compliant, Powered Device Interface Controllers with Integrated Power MOSFET

  • IEEE 802.3af/at Compliant
  • 2-Event Classification
  • Simplified Wall Adapter Interface

Resources