Page 1
GENERAL DESCRIPTION
December 1998
ML6672*
ATM UTP Transceiver
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
BLOCK DIAGRAM
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
■ Complies with ATM Forum 155Mbps Twisted Pair
Specification
■ Transmitter can be externally turned off for
true quiet line
■ Receiver includes adaptive equalizer
■ Operates over 100 meters of STP or category 5 UTP
Twisted Pair Cable
■ Semi-standard options available
* This Part Is End Of Life As Of August 1, 2000
LPBK TXOFF TVCCA TVCCD
TXIN+
Please See ML6674 for New Designs
TXIN–
SD+
SD–
RXOUT+
RXOUT–
MUX
ADAPTIVE
CONTROL REFERENCE
RSET2RSET1
TGNDDTGNDA
RTH1
LINK
STATUS
ADAPTIVE
CONTROL
ADAPTIVE
EQUALIZER
GND
RTH2
RTSET
RTSET1 RTSET2
TPOUT+
TPOUT–
CAP1
TPIN+
TPIN–
RRSET2RRSET1
CMREFRVCCDRVCCARRSET
CAP2
1
Page 2
ML6672
PIN CONFIGURATION
ML6672
32-Pin PLCC (Q32)
RXOUT–
RVCCA
CAP1
CAP2
RTSET1
TVCCD
CMREF
RTSET2
RXOUT+
RVCCD
SD–
SD+
N/C
TGNDD
LPBK
TXOFF
N/C
4 3 2 1 32 31 30
5
6
7
8
9
10
11
12
13
14 15 16 17 18 19 20
TXIN–
TXIN+
TPIN+
TPIN–
TPOUT–
TPOUT+
29
28
27
26
25
24
23
22
21
RRSET1
RRSET2
RSET1
RSET2
RGND
RTH1
RTH2
TVCCA
TGNDA
RRSET1
TPIN–
TPIN+
CMREF
CAP2
CAP1
RVCCA
RXOUT–
ML6672
32-Pin TQFP (H32-7)
RRSET2
RSET1
RSET2
RGND
SD+
RTH1
N/C
32 31 30 29 28 27 26 25
1
2
3
4
5
6
7
8
9 10111213141516
SD–
RVCCD
RXOUT+
RTH2
TVCCA
LPBK
TGNDD
TGNDA
24
23
22
21
20
19
18
17
TXOFF
TPOUT–
TPOUT+
RTSET2
RTSET1
TVCCD
TXIN–
TXIN+
N/C
PIN DESCRIPTION
NAME FUNCTION NAME FUNCTION
TXIN+, TXIN– These differential ECL100K compatible
inputs receive NRZ data from the PHY for
transmission.
TPOUT+, Outputs from the NRZ buffer drive these
TPOUT– differential current outputs. The
transmitter filter/transformer module
connects the media to these pins.
LPBK This TTL input enables transmitter-
Receiver loopback internally when
asserted low.
TXOFF This TTL input forces the NRZ buffer to a quiet
state when asserted low.
RTSET1, An external 1% resistor connected
RTSET2 between these pins controls the
transmitter output current amplitude.
I
= 64 x 1.25V/RTSET
OUT
TVCCA, Separate analog and digital
TVCCD transmitter power supply pins help to
isolate sensitive circuitry from noise
generating digital functions. Both supplies
are nominally +5 volts.
TGNDA, Analog and digital transmitter grounds
TGNDD provide separate return paths for clean
and noisy signals.
SD+, SD– These differential ECL100K compatible
outputs indicate the presence of a data
signal with an amplitude exceeding a
preset threshold.
TPIN+, TPIN– NRZ encoded data from the receiver filter/
transformer module enters the Receiver
through these pins.
RXOUT+, Differential ECL100K compatible outputs
RXOUT– provide NRZ encoded data to the PHY.
CAP1, CAP2 Two external capacitors connected to
these pins sets the time constant for the
adaptation in the equalizer loop as well
as for signal detect response.
RRSET1, Internal time constants controlling the
RRSET2 equalizer’s transfer function are set by an
external resistor connected across these
pins.
CMREF This pin provides a DC common mode
reference point for the receiver inputs.
RVCCA, Analog and digital supply pins are
RVCCD separated to isolate clean and noisy
circuit functions. Both supplies are
nominally +5 volts.
RGND Receiver ground.
RSET1, RSET2 An external 5kW resistor across these pins
sets up an internal reference current.
RTH1, RTH2 An external resistor connected across
these pins sets the internal levels for
equalization as well as signal detect. This
resistor allows compensation for transmit
and magnetics variations. RTH should be
set to match the peak-to-peak transmit
amplitude. V
where V
AMP
amplitude of the transmit output with
zero length cable.
= 16 x 1.25 x RTH/RSET
AMP
is the peak-to-peak
2
Page 3
ML6672
ABSOLUTE MAXIMUM RATINGS
Lead Temperature (Soldering, 10 sec) ..................... 260°C
Thermal Resistance (qJA)
Absolute maximum ratings are those values beyond which
the device could be permanently damaged. Absolute
PLCC ............................................................... 60°C/W
TQFP ................................................................80°CW
maximum ratings are stress ratings only and functional
device operation is not implied.
VCC Supply Voltage Range .................. GND –0.3V to 6V
Input Voltage Range
Digital Inputs ........................ GND –0.3V to VCC + 0.3
Output Current
TPOUT+/TPOUT–, SD±, RXOUT± ..................... 50mA
All other outputs ................................................. 10mA
Junction Temperature ............................................. 150°C
Storage Temperature .............................. –65°C to +150°C
OPERATING CONDITIONS
VCC Supply Voltage .......................................... 5V ± 5%
TA, Ambient Temperature .............................0°C to +70°C
RTSET ............................................................. 4KW ± 1%
RRSET ........................................................ 9.53KW ± 1%
RSET ............................................................... 5KW ± 1%
RTH .............................................................. 250W ± 1%
CAP1, CAP2 .................................................. 1.0µF + 5%
Receive transformer insertion loss...................... < –0.5dB
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, TA = T
PARAMETER CONDITIONS MIN TYP MAX UNITS
DC Characteristics
Supply Current
RVCCD 67 mA
RVCCA 52 mA
TVCCD 25 mA
TVCCA 6mA
RVCCD + RVCCA + TVCCD + TVCCA 170 mA
TTL Inputs (TXOFF, LPBK)
VIL Input Low Voltage 0.8 V
VIH Input High Voltage 2.0 V
Differential Inputs (TPIN±, TXIN±)
TPIN+, TPIN–
Common Mode Input Voltage 2.2 V
TPIN+, TPIN–
Differential Input Voltage 1.5 V
TPIN+, TPIN–
Differential Input Resistance 10 kW
TPIN+, TPIN–
Common Mode Input Current +10 uA
TXIN+, TXIN–
Input Voltage HIGH (VIH)V
TXIN+, TXIN–
Input Voltage LOW (VIL)V
TXIN+, TXIN–
Input Current LOW (IIL) 0.5 uA
TXIN+, TXIN–
Input Current HIGH (IIH) 50 uA
Differential Outputs (SD±, RXOUT±, TPOUT±)
SD+, SD–, RXOUT+, RXOUT–
Output Voltage HIGH (VOH) Note 5 VCC–1.025 VCC–0.88 V
SD+, SD–, RXOUT+, RXOUT–
Output Voltage LOW (VOL) Note 5 VCC–1.81 VCC–1.62 V
MIN
to T
, VCC = 5V ±5%, RTSET = 4.0Ký, RTH = 250ý.
MAX
–1.165 VCC–0.88 V
CC
–1.810 VCC–1.475 V
CC
CC
V
3
Page 4
ML6672
ELECTRICAL CHARACTERISTICS (Continued)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Differential Outputs (SD±, RXOUT±, TPOUT±) (Continued)
TPOUT+, TPOUT–
Differential Output Current HIGH V
TPOUT+, TPOUT–
DifferentialOutput Current LOW V
TPOUT+, TPOUT–
Output Current Offset Note 3 0.5 mA
TPOUT+, TPOUT–V
OUT
= V
CC
Output Amplitude Error Note 3, 4 –5.0 5.0 %
TPOUT+, TPOUT–V
= VCC ±1.1V
OUT
Output Voltage Compliance –2.0 +2.0 %
AC Characteristics
TPOUT+, TPOUT–
Rise/Fall Time Note 2 1.5 2.0 2.5 ns
TPOUT+, TPOUT–
Output Jitter Note 2 0.5 ns
RXOUT+, RXOUT–
Rise/Fall Time Note 2 5 ns
RXOUT+, RXOUT–
Output Jitter Note 2 2.0 ns
= VCC ± 0.5, Note 4 19.0 21.0 mA
OUT
= VCC ± 0.5, Note 4 0 0.1 mA
OUT
Note 1. Absolute maximum ratings are limits beyond which the life of the integrated circuit may be impaired. All voltages unless otherwise specified are measured with
Note 2. Limits are guaranteed by 100% testing, sampling, or correlation with worst-case test conditions.
Note 3. Low Duty cycle pulse testing is performed at T
Note 4. Output current amplitude is determined by I
Note 5. Output voltage levels are specified when terminated by 50W to V
respect to ground.
.
A
= 64 x 1.25V/RTSET.
OUT
-2V or equivalent load.
CC
4
Page 5
FUNCTIONAL DESCRIPTION
ML6672
The ML6672 transceiver is a physical media dependent
transceiver that allows the transmission and reception of
155 Mbps data over shielded twisted pair cable or
category 5 unshielded twisted pair cable.
The transmit section accepts NRZ data, sending the
information on a two pin current driven transmitter. The
transmitted output passes through an external low pass
filter and transformer before entering the connectors to the
STP or UTP cable. The output amplitude of the transmitted
signal is programmable through the external RTSET resistor.
The receive section accepts NRZ coded data after it
passes through an isolation transformer and band limiting
filter. The adaptive equalizer is used to compensate for the
amplitude and phase distortion incurred from the cable. The
adaptive control section determines the cable length and
adjusts the equalizer accordingly. As the input signal
amplitude diminishes, the amount of equalization increases
until it reaches its maximum of an equivalent 100 meters of
category 5 cable. A parallel 10pF capacitor can be connected
between TPIN+ and TPIN– to improve Bit Error Rate.
The adaptive control block governs both the equalization
level as well as the link detection status. The link detection
threshold has a fixed relationship to the overall
equalization level which is currently 25% of the
transmitted amplitude. For the link status to be true, a
minimum level signal must be received. When the input
signal is small, the equalization will be at its maximum.
After the signal has been equalized, it is fed through the
loopback multiplexer onto the RXOUT± pins.
Figure 1 shows a typical gain vs frequency plot of the
adaptive equalizer for 0, 25, 50, 75 and 100 meter
category 5 cable lengths.
TRANSMISSION
PECL level scrambled NRZ data is received by the
ML6672 and the current driven transmitter then sent the
data to the filter/transformer module. The transmit
amplitude is controlled by one external resistor, RTSET.
ADAPTIVE EQUALIZATION
During transmission of data over UTP (unshielded twisted
pair), distortion and ISI are caused by dispersion in the
cable. Equalization is used to overcome this signal
corruption. However, the distortion is frequency
dependent and loop length dependent. Therefore, in most
practical cases, the TP port characteristic is unknown and
it is impractical to tune the equalizer specifically to each
individual port. Hence, adaptive equalizer is used in the
TP-PMD to ensue proper compensation of the received
signal.
By using adaptive equalizer, the receiver automatically
compensate different length of cable without over
equalizing or under equalizing the line. The ML6672
monitors the energy of the received signal to determine
the cable length and adjust the equalizer accordingly. The
input signal level is inversely proportional to the cable
length. Therefore, as the signal level decreases, the
amount of equalization is increased to compensate for the
line loss.
RECEIVE CIRCUIT
After the data is received and equalized, it is then sent to
the clock recovery circuit via the RXOUT pins. A resistor
RTH is used to control the internal level of equalization.
V
AMP
16 125.
´´
=
RTH
RSET
VAMP is the transmit voltage amplitude and is equal to 1V
and RSET = 5kW. Therefore, RTH = 1 x 5/(16 x 1.25) kW =
250W.
CAP1 and CAP2 are capacitors used to set the time
constant for adaptation of the equalizer loop and should
be 0.33µF.
20
I
OUT
64 125.
=
RTSET
V
´
For ATM UTP applications the transmit amplitude is 1V
peak to peak. The termination at the transmitter output is
50W. Therefore the transmit current I
= 1/50 = 20 mA.
OUT
Therefore, RTSET = (64 x 1.25/20)kW = 4kW
The transmitter may be disabled via the TXOFF pin. When
this pin is pulled low, the transmitter’s output goes to its
center value (I
/2) with no differential current flowing
OUT
through the transformer.
15
10
5
0
1 x 10
6
1 x 10
7
Figure 1. Equalization Range
1 x 10
8
1 x 10
9
5
Page 6
ML6672
FROM PHY
NOTE 1
TO PHY
TO PHY
FROM PHY
+5.0V
0.1µF 0.1µF 0.1µF
TXIN+
TXIN–
SD+
SD–
RXOUT+
RXOUT–
LPBK
+5.0V +5.0V +5.0V
TVCCATVCCDRVCCD
TGNDD TGNDA
TXOFF
RVCCA
RGND RTH1
0.33µF
ML6672
0.33µF
CAP1
CAP2
RTH2 RSET1 RSET2
0.1µF
4.0kΩWW 1%
RTSET1
RRSET1 RRSET2
9.53kΩ 1%5kΩ 1%250Ω 1%
RTSET2
TPOUT+
TPOUT–
TPIN+
CMREF
TPIN–
+
50Ω
50Ω
0.1µF
50Ω
+5.0V
50
Ω
10pF
0.1µF
TO MIC
FROM MIC
TRANSFORMER/FILTER MODULE
Figure 2. Application Example of ML6672 Configured for 1.0V
Note 1. Split 100K ECL terminations are 82W and 130W to VCC and GND respectively.
Note 2. Recommended power supply bypass capacitors are 0.1µF with optional 10µF tantalum in parallel.
Note 3. Transformer turns ratio is 1:1.
Note 4. LPBK and TXOFF inputs are active LOW.
6
Transmit Amplitude on C5 UTP.
P-P
Page 7
ML6672
PHYSICAL DIMENSIONS
0.042 - 0.048
(1.07 - 1.22)
9
0.050 BSC
(1.27 BSC)
inches (millimeters)
0.485 - 0.495
(12.32 - 12.57)
0.450 - 0.456
(11.43 - 11.58)
1
PIN 1 ID
0.550 - 0.556
25
(13.97 - 14.12)
17
0.026 - 0.032
(0.66 - 0.81)
0.165 - 0.180
(4.06 - 4.57)
Package: Q32
32-Pin PLCC
0.585 - 0.595
(14.86 - 15.11)
0.148 - 0.156
(3.76 - 3.96)
0.019 - 0.021
(0.48 - 0.51)
0.098 - 0.112
(2.49 - 2.85)
0.025 - 0.045
(0.63 - 1.14)
(RADIUS)
0.490 - 0.530
(12.45 - 13.46)
0.013 - 0.021
(0.33 - 0.53)
0.390 - 0.430
(9.90 - 10.92)
SEATING PLANE
Package: H32-7
32-Pin (7 x 7 x 1mm) TQFP
0.354 BSC
(9.00 BSC)
0.276 BSC
(7.00 BSC)
1
PIN 1 ID
25
0.276 BSC
(7.00 BSC)
17
0.354 BSC
(9.00 BSC)
0º - 8º
0.003 - 0.008
(0.09 - 0.20)
0.018 - 0.030
(0.45 - 0.75)
9
0.032 BSC
(0.8 BSC)
0.012 - 0.018
(0.29 - 0.45)
0.048 MAX
(1.20 MAX)
0.037 - 0.041
(0.95 - 1.05)
SEATING PLANE
7
Page 8
ML6672
ORDERING INFORMATION
PART NUMBER TEMPERATURE RANGE PACKAGE
ML6672CQ (EOL) 0°C to 70°C 32-Pin Leaded PLCC (Q32)
ML6672CH (EOL) 0°C to 70°C 32-Pin TQFP (H32-7)
Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness
of the contents of this publication and reserves the right to make changes to specifications and product
descriptions at any time without notice. No license, express or implied, by estoppel or otherwise, to any
patents or other intellectual property rights is granted by this document. The circuits contained in this
document are offered as possible applications only. Particular uses or applications may invalidate some of
the specifications and/or product descriptions contained herein. The customer is urged to perform its own
engineering review before deciding on a particular application. Micro Linear assumes no liability
whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear
products including liability or warranties relating to merchantability, fitness for a particular purpose, or
infringement of any intellectual property right. Micro Linear products are not designed for use in medical,
life saving, or life sustaining applications.
© Micro Linear 2000. is a registered trademark of Micro Linear Corporation. All other trademarks
are the property of their respective owners.
Products described herein may be covered by one or more of the following U.S. patents: 4,897,611;
4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017;
5,559,470; 5,565,761; 5,592,128; 5,594,376; 5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167;
5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174; 5,767,653; 5,777,514; 5,793,168;
5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165; 5,825,223; 5,838,723;
5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending.
2092 Concourse Drive
San Jose, CA 95131
Tel: (408) 433-5200
Fax: (408) 432-0295
www.microlinear.com
8
DS6672-01
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