Pasadena (MAXREFDES31#): 3.3V and 5V PoE Powered Device - Subsystem Board - Maxim Maxim › Design Support › Technical Documents › Subsystem Boards › Power-Supply Circuits › APP 5840 Keywords: Pasadena MAXREFDES31, powered device (PD), power over Ethernet (PoE) Related Parts SUBSYSTEM BOARD 5840 PASADENA (MAXREFDES31#): 3.
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.
Detailed Description of Hardware Pasadena interfaces to powered Ethernet with an RJ-45 connector (J1). A second RJ-45 (J3) is present to read data out of the system. The MAX5969B provides the complete interface to the Ethernet connection, providing detection signature, classification signature, inrush current control, and 2-event classification. The MAX5969B also interfaces with a wall adaptor input, detecting the wall adaptor input and switching between power sources.
. Activate the PSE power supply or turn on the external DC power supply. 5. Using a voltmeter, verify that MAXREFDES31# provides +3.3V across the +3.3V and GND connections at OUT1. GND is galvanically isolated from the EV kit's input VDD and WAD pads. 6. Repeat steps 2 and 3, connecting the voltmeter to the +5V and GND terminals of OUT2 to verify that MAXREFDES31# provides +5V across the connections at OUT2.
40V 90.41% 89.80% 89.09% 48V 88.97% 90.19% 89.80% 57V 87.20% 90.00% 90.28% Table 3. Line Regulation with Input Voltage Swept from 40V to 57V at No Load and Max Load Conditions Input Load 3.3V 5V 40V to 57V 0W -12.7mV (-0.38%) 20mV (0.40%) 40V to 57V 20.94W -5.5mV (-0.17) 1.8mV (0.04%) Table 4. Load Regulation of 3.3V and 5V Rails Swept from Zero to Full Current While the Other Rail is Held at 0A or Full Output 5.0V swept from 0 to 3A 3.3V swept from 0 to 1.8A Input Voltage 5V = 0A 5V = 3A 3.3V = 0A 3.
Figure 4. Load step at 3.3V (100%, 50%, 100% of 1.8A), 40V input, 5V at 3A. CH1: 3.3V rail, CH2: 5V rail, CH3: 3.3V rail current. Figure 5. Load step at 3.3V (100%, 50%, 100% of 1.8A), 48V input, 5V at 0A. CH1: 3.3V rail, CH2: 5V rail, CH3: 3.3V rail current.
Figure 6. Load step at 3.3V (100%, 50%, 100% of 1.8A), 48V input, 5V at 3A. CH1: 3.3V rail, CH2: 5V rail, CH3: 3.3V rail current. Figure 7. Load step at 3.3V (100%, 50%, 100% of 1.8A), 57V input, 5V at 0A. CH1: 3.3V rail, CH2: 5V rail, CH3: 3.3V rail current.
Figure 8. Load step at 3.3V (100%, 50%, 100% of 1.8A), 57V input, 5V at 3A. CH1: 3.3V rail, CH2: 5V rail, CH3: 3.3V rail current. Figure 9. Load step at 5V (100%, 50%, 100% of 3A), 40V input, 3.3V at 0A. CH1: 3.3V rail, CH2: 5V rail, CH3: 5V rail current.
Figure 10. Load step at 5V (100%, 50%, 100% of 3A), 40V input, 3.3V at 1.8A. CH1: 3.3V rail, CH2: 5V rail, CH3: 5V rail current. Figure 11. Load step at 5V (100%, 50%, 100% of 3A), 48V input, 3.3V at 0A. CH1: 3.3V rail, CH2: 5V rail, CH3: 5V rail current.
Figure 12. Load step at 5V (100%, 50%, 100% of 3A), 48V input, 3.3V at 1.8A. CH1: 3.3V rail, CH2: 5V rail, CH3: 5V rail current. Figure 13. Load step at 5V (100%, 50%, 100% of 3A), 57V input, 3.3V at 0A. CH1: 3.3V rail, CH2: 5V rail, CH3: 5V rail current.
Figure 14. Load step at 5V (100%, 50%, 100% of 3A), 57V input, 3.3V at 1.8A. CH1: 3.3V rail, CH2: 5V rail, CH3: 5V rail current. Other Options of Circuit Operations Besides the 3.3V/1.8A, 5V/3A opto feedback isolated, the Pasadena can support other circuit operations, such as the following: 1. Opto single output of 3.3V/6A 2. Opto single output of 5V/4A 3. Optoless single output of 3.3V/6A 4. Optoless single output of 5V/4A 5. Optoless dual output 3.3V/1.
Related Parts MAX5969B MAX5974A IEEE 802.3af/at-Compliant, Powered Device Interface Controllers with Integrated Power MOSFET Active-Clamped, Spread-Spectrum, Current-Mode PWM Controllers Free Samples Free Samples Next Steps EE-Mail Subscribe to EE-Mail and receive automatic notice of new documents in your areas of interest. Like Share Other Channels Email this page to an associate or friend.
