ML6672 Datasheet, PDF (1/8 Pages) Micro Linear Corporation – ATM UTP Transceiver

December 1998
ML6672*
ATM UTP Transceiver
GENERAL DESCRIPTION
The ML6672 is a complete monolithic transceiver for
155Mbps NRZ encoded data transmission over Category 5
Unshielded Twisted Pair and Shielded Twisted Pair cables.
The ML6672 is compliant with the ATM Forum 155Mbps
Twisted Pair Specification. The adaptive equalizer in the
ML6672 will accurately compensate for line losses of up
to 100m of UTP. The part requires only external 1%
resistors for accurate equalization.
The ML6672 receive section consists of an equalizing filter
with a feedback loop for controlling effective line
compensation. The feedback loop contains a filter and
detection block for determining the proper control signal.
An ECL 100K compatible buffer at the output interfaces
directly with ATM physical interface chips.
The ML6672 transmit section accepts ECL 100K
compatible NRZ inputs.
Several additional functions are provided by the ML6672
to simplify applications. A common-mode reference is
provided to set the input DC level for the equalizer and
the near-end transformer winding. This terminal may be
used as an AC ground for the transformer center-tap or
termination resistors. A link status circuit monitors line
integrity and provides a proper logic level output signal to
interface with the host system.
The ML6672 is implemented in a BiCMOS process. A
differential signal path throughout minimizes the effects of
power supply transients and noise.
FEATURES
s Complies with ATM Forum 155Mbps Twisted Pair
Specification
s Transmitter can be externally turned off for
true quiet line
s Receiver includes adaptive equalizer
s Operates over 100 meters of STP or category 5 UTP
Twisted Pair Cable
s Semi-standard options available
* This Part Is End Of Life As Of August 1, 2000
Please See ML6674 for New Designs BLOCK DIAGRAM
LPBK
TXIN+
TXOFF
TVCCA
TVCCD
RTSET
RTSET1
RTSET2
TPOUT+
TXIN–
TPOUT–
SD+
SD–
RXOUT+
RXOUT–
LINK
STATUS
MUX
ADAPTIVE
CONTROL REFERENCE
ADAPTIVE
CONTROL
ADAPTIVE
EQUALIZER
CAP1
CAP2
TPIN+
TPIN–
RSET1
TGNDA TGNDD
RSET2
RTH1
GND
RTH2
RRSET1
RRSET2
RRSET RVCCA RVCCD CMREF
1