Linear Technology DC1815A Demo Manual

DESCRIPTION
Demonstration circuit 1815A features the
power sourcing equipment (PSE) controller, capable of
delivering up to 90W of LTPoE ++ ™ power to a compatible
LTPoE ++ powered device (PD). A proprietary detection/
classification scheme allows mutual identification between
an LTPoE ++ PSE and LTPoE ++ PD while remaining com-
patible and interoperable with existing Type 1 (13W) and
Type 2 (25.5W) PDs. The LTC4266A feature set is a superset
of the popular LTC4266. These PSE controllers utilize low
R external MOSFETs and 0.25Ω sense resistors which
ON
are especially important at the LTPoE ++ current levels to
maintain the lowest possible heat dissipation.
The LTC4266A is available in multiple power grades, allow-
ing delivered PD power of 13W, 25.5W, 38.7W, 52.7W, 70W
and 90W. The DC1815A has four variations DC1815A-A,
DC1815A-B, DC1815A-C, and DC1815A-D which accom-
modate the four LTPoE ++ power levels (Table 1).
Advanced power management features of the LTC4266A
include: a 14-bit current monitoring ADC, DAC-program-
mable current limit, and versatile quick port shutdown.
Advanced power management host software is available
under a no-cost license. PD discovery uses a proprietary
dual mode 4-point detection mechanism ensuring excellent
immunity from false PD detection. The LTC4266A includes
Table 1. DC1815A Power Levels and Power Supply
DEMO BOARD
DC1815A-A
DC1815A-B
DC1815A-C
DC1815A-D
*Recommended DC1815A power supply minimum to avoid drooping in a worst-case scenario with I
54.75V to 57V for LTPoE ++ compliance
Quad LTPoE ++ PSE Controller
LTC 4266A quad an I
®
2
I
points or a 14-pin ribbon cable for DC590 QuikEval™ GUI
operation.
The LTC4266A is configurable on the DC1815A as an AUTO
pin high, MID pin high, autonomous midspan power injec-
tor; input data from an existing network system is sent out,
along with power, to a PD. The LTC4266A autonomously
detects a PD, turns power on to the port, and discon-
nects port power without the need for a microcontroller.
OUTn LEDs indicate that port power is present. A single
55V supply is required to power the DC1815A. A simple
LDO regulator circuit on the board powers the digital sup-
ply of the LTC4266A. A SHDN pushbutton for each port
shuts down the respective port and disables detection.
Pre-programmed masked shutdown ports are shut down
with the MSD pushbutton. A RESET pushbutton resets the
LTC4266A to its AUTO pin logic state. Ports shut down
with the SHDN or MSD pushbutton must be re-enabled
via I
Design files for this circuit board are available at
http://www.linear.com/demo/DC1815A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
LTPoE ++ and QuikEval are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
PSE CONTROLLER
LTC4266A-1
LTC4266A-2
LTC4266A-3
LTC4266A-4
DEMO MANUAL DC1815A
2
C serial interface operable up to 1MHz. Optional
C control is accessed on the DC1815A either with test
2
C or a device reset with the AUTO pin high.
MAX DELIVERED PD POWER
38.7W
52.7W
70W
90W
current at all four ports. Set the voltage between
LIM
LTC4266A
POWER SUPPLY*
300W
300W
420W
540W
dc1815afd
1