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Teilenummer | EQCO875SC.3 |
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Beschreibung | Single-Coax Transceiver | |
Hersteller | Microchip | |
Logo | ||
Gesamt 20 Seiten EQCO875SC.3/EQCO850SC.3
EQCO875SC.3/EQCO850SC.3 Single-Coax Transceiver for
Fast Ethernet
Features
• Combined Transmitter and Receiver with an
Integrated Equalizer to Form a Full-Duplex
Bidirectional Connection over a Single 75Ω Coax
Cable (EQCO875SC.3) or 50Ω Coax Cable
(EQCO850SC.3)
• Compatible with FX Version of Fast Ethernet
• Low-Power: 205 mW from Single 3.3V Supply
• Integrated Termination Resistors for Low External
Discrete Count
• Fully Supports PoE-Based Power and Data
Signal Distribution Over Coax
• 16-Pin, 0.65 mm Pin Pitch, 4 mm QFN Package
• Pb-Free and RoHS Compliant
Applications
This solution is useful and economical for many
markets and applications, including the following:
• Camera Networks
- Home Security, Surveillance, Industrial/
Inspection, Medical Cameras
• Home Networking over Coax Infrastructure
- When Cat5 or Cat6 cabling is not available
and existing 75Ω coax is not used for analog
TV signals
• TV, STB, PVR Connections Including Inter-Room
Links
TABLE 1: TYPICAL DEVICE PERFORMANCE FOR EQCO875SC.3
Version
EQCO875SC.3 Range Using
RG11
RG6 (Ø 5 mm)
EQCO875SC.3
225m
150m
TABLE 2: TYPICAL DEVICE PERFORMANCE FOR EQCO850SC.3
Version
RG174
EQCO850SC.3 Range Using
RTK
EQCO850SC.3
40m 70m
RG58
70m
2009-2016 Microchip Technology Inc.
DS60001314A-page 1
EQCO875SC.3/EQCO850SC.3
2.0 CIRCUIT OPERATION
2.1 Pre-Driver
The pre-driver removes any dependency on Ethernet
PHY for the amplitude and rise time of the outgoing
signal on SDIO.
2.2 Active Signal Splitter/Combiner
The Active Splitter/Combiner controls the amplitude
and rise time of the outgoing coax signal and transmits
it via a precise 75Ω output termination resistor. The
output resistor, when balanced with the coax
characteristic impedance, also forms part of a hybrid
splitter circuit which subtracts the TX output from the
signal on the SDIO output to give yield the far-end TX
signal. The return-loss of the coax termination is a key
factor in the performance of the line hybrid.
2.3 Equalizer Core
The EQCO875SC-HS has an embedded high-speed
equalizer in the receive path with unique characteristics:
• Auto-adaptive
The equalizer controls a multiple-pole analog filter
which compensates for attenuation of the cable, as
illustrated in Figure 2-1. The filter frequency response
needed to restore the signal is automatically determined
by the device using a time-continuous feedback loop
that measures the frequency components in the signal.
Upon the detection of a valid signal, the control loop
converges within a few microseconds.
• Variable gain
EQCO875SCs are used in pairs, with one at each end of
the coax cable. The EQCO875SC can be used with any
Fast Ethernet compliant fiber optic PHY; any differences
in transmit amplitude are removed by the input pre-driver.
The receiver equalizer has variable gain to compensate
for attenuation through the coax cable.
FIGURE 2-1:
PRINCIPLE OF EQUALIZER OPERATION
DS60001314A-page 6
2009-2016 Microchip Technology Inc.
6 Page EQCO875SC.3/EQCO850SC.3
16-Lead Plastic Quad Flat, No Lead Package (8E) - 4x4x0.9 mm Body [QFN]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
NOTE 1
D
N
AB
1
2
(DATUM B)
(DATUM A)
2X
0.20 C
2X
0.20 C
TOP VIEW
CA
SEATING
PLANE
(A3)
0.10
SIDE VIEW
CAB
D2
(16X K)
E
0.10 C
A1
16X
0.08 C
0.10 C A B
e2
2
1
E2
16X L
N
16X b
e
BOTTOM VIEW
0.10 C A B
0.05 C
Microchip Technology Drawing C04-259B Sheet 1 of 2
DS60001314A-page 12
2009-2016 Microchip Technology Inc.
12 Page | ||
Seiten | Gesamt 20 Seiten | |
PDF Download | [ EQCO875SC.3 Schematic.PDF ] |
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