EQCO875SC.3 Datasheet, PDF (7/20 Pages) Microchip Technology – EQCO875SC.3/EQCO850SC.3 Single-Coax Transceiver for Fast Ethernet

EQCO875SC.3/EQCO850SC.3
3.0 APPLICATION INFORMATION
Figure 3-1 illustrates a typical schematic implementation
for the EQCO875SC.3 in Ethernet mode.
FIGURE 3-1:
EQCO875SC.3 TYPICAL APPLICATION CIRCUIT
48V_DC
J1
GND
FB1
C10 1u
100V
L1
C9 10n
1
C5 10n
2
100V
R1 _{C6 10n}
3
50R/75R
100V
4
GND
AVCC
SDIO
REF
AGND
VCC GND
C8 10u
C7 100n
U1
EQCO850SC.3/EQCO875SC.3
SDOp ¹²
SDOn ¹¹
SDIp ¹⁰
SDIn ⁹
C3 100n
C4 100n
C1 100n
C2 100n
SDOp
SDOn
SDIp
SDIn
VCC
GND
To improve isolation from noise on the board power
plane and improve EMC immunity and emissions, it is
recommended to power the transmit side of the
equalizer (AVCC) through a ferrite bead (FB1). C9 is
used to reference AVCC to the ground directly at the
connector J1, while AGND is also connected directly to
the connector.
A 100 nF decoupling capacitor (C7) should be placed
as close as possible between the DVCC pin and the
DGND pin. The REF and SDIO signals are AC-coupled
with identical capacitors, C5 and C6. Termination resis-
tor R1 should match the characteristic impedance of
the system, 50Ω for EQCO850SC.3 and 75Ω for
EQCO875SC.3.
A CoilCraft 1812PS-103KLB inductor (L1) is
recommended for best performance when using power
over coax. L1 and C10 can be removed if power over
coax is not required.
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DS60001314A-page 7