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. 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 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. FEATURES The ML6672 is implemented in a BiCMOS process. A differential signal path throughout minimizes the effects of power supply transients and noise. ■ ■ 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 ■ 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 BLOCK DIAGRAM s n g i s e D w e N r o f 4 7 6 6 L M e e S Please LPBK TXOFF TVCCA RTSET TVCCD RTSET1 RTSET2 TXIN+ TPOUT+ TXIN– TPOUT– SD+ LINK STATUS SD– CAP1 ADAPTIVE CONTROL CAP2 RXOUT+ MUX TPIN+ ADAPTIVE EQUALIZER RXOUT– TPIN– ADAPTIVE CONTROL REFERENCE RSET1 RSET2 TGNDA TGNDD RTH1 RRSET1 GND RTH2 RRSET2 RRSET RVCCA RVCCD CMREF 1 ML6672 PIN CONFIGURATION ML6672 32-Pin TQFP (H32-7) RGND RTH1 RTH2 TVCCA TGNDA 32 31 30 RSET2 CMREF 1 RSET1 CAP2 2 RRSET2 CAP1 3 TPIN– RVCCA 4 TPIN+ RXOUT– ML6672 32-Pin PLCC (Q32) 32 31 30 29 28 27 26 25 RXOUT+ 5 29 RRSET1 RRSET1 1 24 TPOUT– RVCCD 6 28 RRSET2 TPIN– 2 23 TPOUT+ SD– 7 27 RSET1 TPIN+ 3 22 RTSET2 SD+ 8 26 RSET2 CMREF 4 21 RTSET1 N/C 9 25 RGND CAP2 5 20 TVCCD TGNDD 10 24 RTH1 CAP1 6 19 TXIN– LPBK 11 23 RTH2 RVCCA 7 18 TXIN+ RXOUT– 8 11 12 13 14 15 16 TGNDD LPBK TXOFF RXOUT+ TPOUT– RTSET2 TPOUT+ RTSET1 TVCCD TXIN– TXIN+ 10 N/C 9 14 15 16 17 18 19 20 SD+ N/C 13 17 N/C SD– 21 TGNDA RVCCD 22 TVCCA TXOFF 12 PIN DESCRIPTION NAME FUNCTION NAME FUNCTION TXIN+, TXIN– These differential ECL100K compatible inputs receive NRZ data from the PHY for transmission. Outputs from the NRZ buffer drive these differential current outputs. The transmitter filter/transformer module connects the media to these pins. This TTL input enables transmitterReceiver loopback internally when asserted low. This TTL input forces the NRZ buffer to a quiet state when asserted low. An external 1% resistor connected between these pins controls the transmitter output current amplitude. IOUT = 64 x 1.25V/RTSET Separate analog and digital transmitter power supply pins help to isolate sensitive circuitry from noise generating digital functions. Both supplies are nominally +5 volts. Analog and digital transmitter grounds provide separate return paths for clean and noisy signals. These differential ECL100K compatible outputs indicate the presence of a data signal with an amplitude exceeding a preset threshold. NRZ encoded data from the receiver filter/ transformer module enters the Receiver through these pins. RXOUT+, RXOUT– CAP1, CAP2 Differential ECL100K compatible outputs provide NRZ encoded data to the PHY. 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. Internal time constants controlling the equalizer’s transfer function are set by an external resistor connected across these pins. This pin provides a DC common mode reference point for the receiver inputs. Analog and digital supply pins are separated to isolate clean and noisy circuit functions. Both supplies are nominally +5 volts. Receiver ground. An external 5kW resistor across these pins sets up an internal reference current. 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. VAMP = 16 x 1.25 x RTH/RSET where VAMP is the peak-to-peak amplitude of the transmit output with zero length cable. TPOUT+, TPOUT– LPBK TXOFF RTSET1, RTSET2 TVCCA, TVCCD TGNDA, TGNDD SD+, SD– TPIN+, TPIN– 2 RRSET1, RRSET2 CMREF RVCCA, RVCCD RGND RSET1, RSET2 RTH1, RTH2 ML6672 ABSOLUTE MAXIMUM RATINGS Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute 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 Lead Temperature (Soldering, 10 sec) ..................... 260°C Thermal Resistance (qJA) PLCC ............................................................... 60°C/W TQFP ................................................................ 80°CW 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 = TMIN to TMAX, VCC = 5V ±5%, RTSET = 4.0Ký, RTH = 250ý. PARAMETER CONDITIONS MIN TYP MAX UNITS DC Characteristics Supply Current RVCCD 67 mA RVCCA 52 mA TVCCD 25 mA TVCCA 6 mA RVCCD + RVCCA + TVCCD + TVCCA 170 mA 0.8 V TTL Inputs (TXOFF, LPBK) VIL Input Low Voltage VIH Input High Voltage 2.0 V Differential Inputs (TPIN±, TXIN±) TPIN+, TPIN– Common Mode Input Voltage 2.2 TPIN+, TPIN– Differential Input Voltage TPIN+, TPIN– Differential Input Resistance VCC V 1.5 V kW 10 TPIN+, TPIN– Common Mode Input Current +10 uA TXIN+, TXIN– Input Voltage HIGH (VIH) VCC–1.165 VCC–0.88 V TXIN+, TXIN– Input Voltage LOW (VIL) VCC–1.810 VCC–1.475 V TXIN+, TXIN– Input Current LOW (IIL) 0.5 TXIN+, TXIN– Input Current HIGH (IIH) uA 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 3 ML6672 ELECTRICAL CHARACTERISTICS (Continued) PARAMETER CONDITIONS MIN TYP MAX UNITS Differential Outputs (SD±, RXOUT±, TPOUT±) (Continued) TPOUT+, TPOUT– Differential Output Current HIGH VOUT = VCC ± 0.5, Note 4 19.0 21.0 mA TPOUT+, TPOUT– DifferentialOutput Current LOW VOUT = VCC ± 0.5, Note 4 0 0.1 mA TPOUT+, TPOUT– Output Current Offset Note 3 0.5 mA TPOUT+, TPOUT–VOUT = VCC Output Amplitude Error Note 3, 4 –5.0 5.0 % –2.0 +2.0 % 2.5 ns TPOUT+, TPOUT–VOUT = VCC ±1.1V Output Voltage Compliance AC Characteristics TPOUT+, TPOUT– Rise/Fall Time Note 2 TPOUT+, TPOUT– Output Jitter Note 2 RXOUT+, RXOUT– Rise/Fall Time Note 2 RXOUT+, RXOUT– Output Jitter Note 2 Note 1. Note 2. Note 3. Note 4. Note 5. 4 1.5 2.0 0.5 ns 5 2.0 ns ns Absolute maximum ratings are limits beyond which the life of the integrated circuit may be impaired. All voltages unless otherwise specified are measured with respect to ground. Limits are guaranteed by 100% testing, sampling, or correlation with worst-case test conditions. Low Duty cycle pulse testing is performed at TA. Output current amplitude is determined by IOUT = 64 x 1.25V/RTSET. Output voltage levels are specified when terminated by 50W to VCC-2V or equivalent load. ML6672 FUNCTIONAL DESCRIPTION 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. IOUT = 64 ´ 125 . V RTSET For ATM UTP applications the transmit amplitude is 1V peak to peak. The termination at the transmitter output is 50W. Therefore the transmit current IOUT = 1/50 = 20 mA. 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 (IOUT/2) with no differential current flowing through the transformer. 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. VAMP = 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 15 10 5 0 1 x 106 1 x 107 1 x 108 1 x 109 Figure 1. Equalization Range 5 ML6672 +5.0V +5.0V +5.0V 0.1µF 0.1µF RVCCD 0.1µF TVCCD 0.1µF TVCCA RVCCA 0.33µF 0.33µF CAP1 CAP2 RTSET1 0.1µF RTSET2 50 Ω TPOUT+ TXIN+ FROM PHY +5.0V 4.0kΩWW 1% TXIN– 50Ω NOTE 1 SD+ TO PHY SD– TPOUT– ML6672 TPIN+ 50Ω RXOUT+ TO PHY CMREF RXOUT– 50Ω TPIN– LPBK TXOFF TGNDD TGNDA RGND RTH1 RTH2 RSET1 RSET2 RRSET1 RRSET2 FROM PHY 250Ω 1% 5kΩ 1% 10pF + 0.1µF 9.53kΩ 1% Figure 2. Application Example of ML6672 Configured for 1.0VP-P Transmit Amplitude on C5 UTP. Note 1. Note 2. Note 3. Note 4. 6 Split 100K ECL terminations are 82W and 130W to VCC and GND respectively. Recommended power supply bypass capacitors are 0.1µF with optional 10µF tantalum in parallel. Transformer turns ratio is 1:1. LPBK and TXOFF inputs are active LOW. TRANSFORMER/FILTER MODULE +5.0V TO MIC FROM MIC ML6672 PHYSICAL DIMENSIONS inches (millimeters) Package: Q32 32-Pin PLCC 0.485 - 0.495 (12.32 - 12.57) 0.098 - 0.112 (2.49 - 2.85) 0.450 - 0.456 (11.43 - 11.58) 1 PIN 1 ID 0.042 - 0.048 (1.07 - 1.22) 9 25 0.490 - 0.530 (12.45 - 13.46) 0.550 - 0.556 0.585 - 0.595 (13.97 - 14.12) (14.86 - 15.11) 17 0.019 - 0.021 (0.48 - 0.51) 0.050 BSC (1.27 BSC) 0.165 - 0.180 (4.06 - 4.57) 0.026 - 0.032 (0.66 - 0.81) 0.025 - 0.045 (0.63 - 1.14) (RADIUS) 0.148 - 0.156 (3.76 - 3.96) 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) 0º - 8º 0.003 - 0.008 (0.09 - 0.20) 25 1 PIN 1 ID 0.276 BSC (7.00 BSC) 0.354 BSC (9.00 BSC) 0.018 - 0.030 (0.45 - 0.75) 17 9 0.032 BSC (0.8 BSC) 0.012 - 0.018 (0.29 - 0.45) 0.048 MAX (1.20 MAX) SEATING PLANE 0.037 - 0.041 (0.95 - 1.05) 7 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