Linear Technology DC1680B, Руководство пользователя

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dc1843bfa
DEMO MANUAL DC1843B
DEMONSTRATION CIRCUIT 1680B OPERATION
Demonstration circuit 1680B is configured as an 8-Port,
IEEE802.3at Type 1 and Type 2 PoE PSE motherboard in
the DC1843B kit. This board accepts various PSE daughter
cards featuring Linear Technology PSE controllers. The
DC1680B is capable of powering up to 8 PDs.
Daughter Card Insertion Precautions
When inserting or removing the daughter card into the
DC1680B, verify all supplies and LEDs are off. Push the
card straight down for insertion or pull straight up for
removal to avoid bending the connector pins. Follow the
instructions in the Quick Start Procedure for alignment.
V
EE
Supply
Connect a power supply for V
EE
with the positive rail to POS
and negative rail to NEG as shown in Figure 3 of the Quick
Start Procedure. Set the voltage within the range in Table 1
depending on whether the application is a Type 1 or Type 2.
Choose a power supply rating and set the current limit
high enough to provide power for the maximum number of
PDs connected and to meet each PD power requirements.
Table 1. DC1843B V
EE
Power Range for Type 1 and Type 2 PSEs
PSE TYPE
V
EE
SUPPLY
RANGE
MAX DELIVERED
PORT POWER
POWER
SUPPLY*
Type 1 45V to 57V 13W 200W
Type 2 51V to 57V 25.5W 400W
*Recommended DC1843B power supply minimum to avoid drooping in
a worst-case scenario with I
LIM
current at all 8 ports.
PD Connection
PDs are connected using an Ethernet cable to any of the
8 ports at the 2×6, RJ45 connector J4 on the DC1680B
(Figure 3). Test points for port outputs OUT1 through
OUT8 are provided.
8-Port Configuration
The DC1680B is configured for an 8-port PSE motherboard
for the DC1843B kit. Four RJ45 dust caps at J3 and four
dust caps at J4 are inserted to block off the four unused
Ethernet ports. Additional pegs are placed in the last 4
pins of connector J1 to block off the unused pins when
the DC1842B daughter card is inserted.
DC1680B USER FEATURES
Refer to Figure 12 and Figure 13 for the following user
features.
Onboard 3.3V Supply
The DC1680B has an onboard V
DD33
digital supply gen-
erated from the V
EE
supply. DGND is a negative voltage
referenced to AGND. If an external 3.3V supply is to be
used, contact Linear Technology Applications for proper
connection.
V
EE
and V
DD33
LED Indicators
LEDs for V
EE
and V
DD33
indicate if voltage is present at
these supplies. Verify these LEDs are off before inserting
or removing the daughter card.
Digital Connections
The DC1680B has connections for I
2
C control from a
host controller. The DC590 is optionally connected to
the DC1680B at J5 through a 14-pin ribbon cable. The
QuikEval software will automatically detect the DC1680B
and open the LTC4271 GUI. A second 14-pin ribbon cable
can be connected to J6 for I
2
C expansion to another
DC1680B board with slight board modifications. Contact
Linear Technology Applications for instructions.
Digital test points include SCL, SDA, DGND,
INT , MSD ,
and RESET . I
2
C address pin AD6, AD3, and AD2 are set
with a 3-bit switch SW3.
Midspan PSE
The DC1843B can be configured as a midspan PSE.
Upstream switch data comes in to J3. Data and PoE go
out to a PD at J4. Set both MID and AUTO pins logic high.