Datasheet

MAX5980 Evaluation Kit
Evaluates: MAX5980
10Maxim Integrated
Figure 4. Advanced User Interface (2-Wire Interface)
General Troubleshooting
Problem: Software reports it cannot find the USB
interface circuit.
• IstheUSBinterfacecircuitpowerLEDD201lit?
• IstheUSBcommunicationscableconnected?
• Has Windows plug-and-play detected the board?
Bring up Control Panel System | Device Manager,
and look at what device nodes are indicated for the
USB. If there is an unknown device node attached to
the USB, delete it—this forces plug-and-play to try
again.
Problem: Software reports MAX5980 IC not found,
exiting program.
• Are the SCL_IN and SDA signals pulled up to
Opto_VCC(3.3V)?
• If using jumper wires to connect could the SCL_IN
andSDAsignalsbeswapped?CouldtheOPTO_GND
groundreturnbemissing?
Detailed Description of Hardware
The MAX5980 EV kit features a 10/100/1000BASE-
TX Ethernet 4-port PSE controller circuit for -48V/-54V
supply rail systems. The EV kit’s PSE circuit uses the
IEEE 802.3af /at-compliant MAX5980 PSE controller, four
n-channel power MOSFETs in 8-pin SO surface-mount
packages, eight surface-mount current-sensing resis-
tors, and four 10/100/1000BASE-TX magnetic modules
(integrated in J2) to form the basic portion of a PSE cir-
cuit. The EV kit has been designed as an IEEE 802.3af/
at-compliant PSE and demonstrates all the required
functions such as PD discovery, classification, current-
limit control of a connected PD at each Ethernet output
port, and DC disconnect detection. A PC can be used
to communicate with the slave IC over the I
2
C interface,
optically coupled logic, and the 2-wire to USB-port inter-
face circuit.