EQCO62T20.3 Datasheet, PDF (7/32 Pages) Microchip Technology – EQCO62T20.3 6.25 Gbps Asymmetric Coax Driver

EQCO62T20.3/EQCO31T20.3
1.2 Circuit Operation
FIGURE 1-3:
EQCO62T20.3 BLOCK DIAGRAM SHOWING ELECTRICAL CONNECTIONS
EQCO62T20.3
SDIp
SDIn
Input
Pre-Driver
Active Signal
Splitter/Combiner
SDOp
SDOn
Transmit
Detection
LF receiver
LFO
LF Output
Driver
1.2.1 PRE-DRIVER
The pre-driver removes any dependency for the
amplitude and rise time of the incoming signal on SDI.
1.2.2
ACTIVE SIGNAL SPLITTER/
COMBINER
The active splitter/combiner controls the amplitude and
rise time of the outgoing coax signal and transmits it via
a 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
SDO output to give yield the far-end TX signal.
1.2.3 TRANSMIT DETECTION
The transmit detection detects if an input signal is
applied at SDI. The detection circuit looks at the signal
amplitude of SDI; if no signal is detected, the pre-driver
and output driver are disabled. The LF receiver then
continues to operate independently. At the moment the
output driver is turned on or off, there can be a bit error
in the uplink channel, e.g. by the LF-receiver.
1.2.4 LF RECEIVER
The uplink receiver removes unwanted crosstalk from
the transmitted near-end signal. Afterwards, the uplink
signal is restored by detecting edges coming from the
uplink signal. At the moment the high-speed output
driver is turned on or off, there can be a bit error in the
uplink channel, e.g. by the LF-receiver. The initial
output state of the LF receiver can be wrong, and
subsequent bits will still be received correctly.
1.2.5 LF OUTPUT DRIVER
The uplink output driver converts the signal detected by
the LF receiver to an LVTTL signal with a controlled rise
and fall time. It is required to set the output signal
amplitude of this LVTTL signal by connecting the LFVCC
to the appropriate power supply voltage (max 3.3V).
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DS60001301B-page 7