December 1998

ATM UTP Transceiver

1

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

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Complies with ATM Forum 155Mbps Twisted Pair

Specification

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Transmitter can be externally turned off for

true quiet line

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Receiver includes adaptive equalizer

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Operates over 100 meters of STP or category 5 UTP

Twisted Pair Cable

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Semi-standard options available

* This Part Is End Of Life As Of August 1, 2000

BLOCK DIAGRAM

LINK

STATUS

ADAPTIVE

CONTROL

ADAPTIVE

EQUALIZER

ADAPTIVE

CONTROL REFERENCE

CMREF

RVCCD

RVCCA

RRSET

RRSET2

RRSET1

GND

RTH2

RTH1

RSET2

RSET1

TGNDD

TGNDA

RXOUT–

RXOUT+

SD–

SD+

TXIN–

TXIN+

TPOUT–

TPOUT+

CAP1

CAP2

TPIN+

TPIN–

LPBK

TXOFF

TVCCA

TVCCD

RTSET

RTSET1

RTSET2

MUX

Please See ML66

74 for New Designs