MAXREFDES31#: 5V @ 3A, 3.3V @ 1.8A, 40 ~ 57V in, POE


Pasadena (MAXREFDES31#) is a highly efficient, flyback, 3.3V and 5V Class 4 powered device (PD) with a 40V to 57V auxiliary input. The design features the MAX5969B as the controller. The MAX5974A controls current-mode PWM converters and provides frequency fold-back for both the auxiliary input and power-over-Ethernet (PoE) applications. The design is a high-performance, compact, IEEE 802.3af/at compliant, cost-efficient solution for a PD with power level up to Class 4. The design can also support the auxiliary-input to provide approximately 21W output power.

The Pasadena (MAXREFDES31#) reference design features the MAX5969B and MAX5974A. The MAX5969B controller is fully compliant with the IEEE 802.3af/at standard in a power-over-Ethernet (PoE) system. The device can also be powered from a wall adapter (WAD). The WAD operates with higher priority than PoE, which is controlled by the MAX5969B. The MAX5974A controls a 40V to 57V input-voltage, current-mode PWM converters and provides frequency fold-back. Using these devices, this reference design is IEEE 802.3af/at compliant. It is also a high-performance, compact, and cost-effective solution for a PD supporting power up to Class 4 power level.


Manufacturer Maxim Integrated
Category Power Management
Sub-Category POE - Power Over Ethernet
Eval Board Part Number MAXREFDES31#-ND
Eval Board Supplier Maxim Integrated
Eval Board Normally In Stock
Compliance IEEE 802.3af (802.3at Type 1)
Outputs and Type 2 Non-Isolated
Voltage Out 3.3 V
5 V
Current Out 1.8 A
3 A
Voltage In 40 - 57 V
Efficiency @ Conditions >90%, 57V in, 10 ~ 22 W
>90%, 48V in, 8 ~ 20 W
>90%, 40V in, 6 ~ 18 W
Internal Switch No
Features Current Limit (Adj. or Fixed)
Frequency Foldback
Frequency Jitter for EMI
Reverse Polarity Protection
Short Circuit Protection
Under Voltage Protection, Brown-Out
Switching Frequency 100 ~ 600 kHz
Component Count + Extras 99 + 10
Design Author Maxim Integrated Products
Application / Target Market PoE, Power Over Ethernet
Security IP Camera
WLAN Access Points
Main I.C. Base Part MAX5969B
Date Created By Author 2014-04
Date Added To Library 2020-05

Share This Design

Eval Board

Order a fully assembled board:

Quantity Available: 9