Datasheet

DEVICE
Apr 15, 2014
Abstract: 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 foldback 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.
Introduction
The Pasadena (MAXREFDES31#) reference design features the MAX5969B and MAX5974A (see Figure 1).
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 foldback. 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.
Figure 1. The Pasadena subsystem design block diagram.
Features Applications
IEEE 802.3af/at compliant
Dual output
Tight line regulation
Low ripple
Excellent load transient response
High efficiency
Security cameras
Wireless access points
Point of sale terminals
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