DC1682B Datasheet, PDF (6/26 Pages) Linear Dimensions Semiconductor – 12-port Type 2 power sourcing equipment (PSE) composed of a DC1682B daughter card and DC1680A mother board.

DEMO MANUAL DC1840B
Demonstration Circuit 1682B Operation
Board Layout
Isolation and Power Supplies
Proper board layout is crucial for proper LTC4270/LTC4271
chipset operation, robustness, and accuracy. When lay-
ing out, pay attention to parts placement, Kelvin sensing,
power paths, and copper fill. It is imperative to follow the
LTC4270/LTC4271 Layout Guide document when laying
out the board.
The LTC4270/LTC4271 chipset provides communication
across an isolation barrier through a data transformer
(Figure 6). This eliminates the need for expensive opto-
couplers. All digital pins reside on the digital ground refer-
ence and are isolated from the analog PoE supply. A 3.3V
supply for V_DD and an isolated V_EE supply are connected
to the DC1682B through the 34-pin connector.
C21
0.1µF
V_DD33
CPD
U1
LTC4271
CND
DPD
DGND ^DND
V_DD33
34-PIN
CONNECTOR
DC1682B SIDE
DC1680A SIDE
–+ ^{VDD33 SUPPLY}
T1
RX^–
R13
100Ω
CT(4)
C23
1µF
R14
100Ω
RX⁺
TX^–
R15
100Ω
CT(2)
C22
1µF
R16
100Ω
TX⁺
WÜRTH 7490100143
RD^–
CT(3)
RD⁺
TD^–
CT
TD⁺
R21
100Ω
R22
100Ω
R23
100Ω
CPA
U2
LTC4270
AGND
CNA
DPA
R24
100Ω
V_EE
DNA
C24, 2nF
2kV
V_EE
V_EE
ISOLATION
R35
10Ω
C19
1µF
100V
D1
SMAJ58A
Figure 6. DC1682B Digital and Analog Isolation
C_BULK
–+
TVS_BULK
V_EE
SUPPLY
DC1840B F06
6
dc1840bfc