Linear Technology DC1366A - LTC4266: 25.5W PoE+ 4-Port Midspan PSE (req. DC590) DC1366A DC1366A Scheda Tecnica
Codici prodotto
DC1366A
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1366A
IEEE802.3AF/AT POWER-OVER-ETHERNET POWER SOURCING EQUIPMENT CONTROLLER
LTC4266
1
DESCRIPTION
Demonstration circuit DC1366A features the
LTC
LTC
®
4266CUHF, a quad network power controller with
I
2
C™ interface, designed for use in IEEE 802.3at™-
compliant Power Sourcing Equipment (PSE). Inte-
grated into a tiny 5mm
grated into a tiny 5mm
×7mm 38-pin QFN package are
four independent ports controlling external N-channel
power MOSFETs. Each port features:
power MOSFETs. Each port features:
■ Reliable 4-point PD detection
■ Selectable 1 or 2-event classification
■ Inrush current limiting
■ Extremely fast short-circuit protection with
■ Selectable 1 or 2-event classification
■ Inrush current limiting
■ Extremely fast short-circuit protection with
programmable foldback current threshold
■ Programmable cutoff current threshold for
class power enforcement
■ Voltage and current readback
■ DC disconnect sensing
■ DC disconnect sensing
The DC1366A board is configured like a midspan
PSE with two RJ45 connectors for each port such
that gigabit Ethernet data can pass through the
board at full line rates while dc power is injected by
the LTC4266 on the PD side of the board.
PSE with two RJ45 connectors for each port such
that gigabit Ethernet data can pass through the
board at full line rates while dc power is injected by
the LTC4266 on the PD side of the board.
Often one of the most challenging aspects of de-
signing a PSE system is the power management
software; Linear Technology makes the job easier
with the fully-featured LTC4266 register set and an
advanced GUI software application. The GUI allows
the user full and easy access to the LTC4266 regis-
ter set with detailed contextual help info. The GUI
also includes a host computer emulator to demon-
strate basic power management techniques: the
user selects various system parameters such as PSE
type (endspan or midspan), 1 or 2-event classifica-
tion, total system power budget, and fault handling
rules; then with the click of a button the host com-
puter emulator takes control of the system, manag-
ing the power budget as PDs are connected and dis-
connected, and logging all events.
signing a PSE system is the power management
software; Linear Technology makes the job easier
with the fully-featured LTC4266 register set and an
advanced GUI software application. The GUI allows
the user full and easy access to the LTC4266 regis-
ter set with detailed contextual help info. The GUI
also includes a host computer emulator to demon-
strate basic power management techniques: the
user selects various system parameters such as PSE
type (endspan or midspan), 1 or 2-event classifica-
tion, total system power budget, and fault handling
rules; then with the click of a button the host com-
puter emulator takes control of the system, manag-
ing the power budget as PDs are connected and dis-
connected, and logging all events.
The DC1366A demo boards, CAD files, and GUI soft-
ware are available only under a non-disclosure
agreement (NDA). Contact your local Linear Tech-
nology sales person or field applications engineer.
ware are available only under a non-disclosure
agreement (NDA). Contact your local Linear Tech-
nology sales person or field applications engineer.
L, LT, LTC, and QuickEval are trademarks of Linear Technology
Corporation; I2C is a trademark of Phillips Electronics N.V.; all other
trademarks are the property of their respective owners.
Corporation; I2C is a trademark of Phillips Electronics N.V.; all other
trademarks are the property of their respective owners.
QUICK START PROCEDURE
Figure 1 shows the basic setup. The LTC4266 requires
two power supply rails: V
two power supply rails: V
DD
(nominally 3.3V) and V
EE
(nominally -54V). The V
DD
supply can be provided by
the DC590B board or an external bench supply.
When running the GUI application on a Windows
computer, the DC590B board from Linear Tech is
used to interface a USB port on the PC to the I
computer, the DC590B board from Linear Tech is
used to interface a USB port on the PC to the I
2
C bus
on the DC1366A board. The DC590B also provides
optoisolation of the I
optoisolation of the I
2
C bus, and an isolated 3.3V
supply to run the LTC4266 chip; the user need only
provide the V
provide the V
EE
supply.
Alternatively, the user can omit the DC590B and
connect some other I
connect some other I
2
C master device to the
DC1366A board. If the DC590B is omitted then a
bench power supply must provide V
bench power supply must provide V
DD
.
For applications where power management is not
required, the LTC4266 features an AUTO mode al-
lowing it to operate completely autonomously.
required, the LTC4266 features an AUTO mode al-
lowing it to operate completely autonomously.
Choose one of the setup procedures shown on the next
page, depending on whether or not the GUI application
software is required.
page, depending on whether or not the GUI application
software is required.