VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Features Applications • SONET/SDH at 622Mb/s, 1.244Gb/s, 2.488Gb/s, and 3.125Gb/s • Full-Speed Fibre Channel (1.062Gb/s) • Small Form Factor (SFF) Receivers • ATM Optical Receivers • 3.3V or 5V Power Supply • Typical Supply Current of 32mA • Current-Mode Logic Outputs • Optional Output Squelch • Loss of Signal Detect • Output Offset Correction • Rise/Fall Times Faster than 100ps • Packages: TSSOP-16, Bare Die General Description The VSC7959 is a single supply limiting amplifier with Loss of Signal (LOS) detect for SONET/SDH and Fibre Channel applications up to 3.125Gb/s. The VSC7959 provides a constant output signal swing for a wide range of input voltages and has Current-Mode Logic (CML) outputs. The VSC7961 provides the same functionality as the VSC7959 with positive emitter-coupled logic (PECL) outputs. Key features of the VSC7959 are its RMS power detectors for programmable LOS detection, optional output squelch, adjustable output levels, excellent jitter performance, and fast edge rates. The VSC7959 is available in die form or in a TSSOP-16 package. Block Diagram VSC7959 VCC 8kΩ LOS VCC 8kΩ TH LOS SQUELCH RMS Power Detect and Control Output Control IN+ LEVEL OUT+ 100Ω OUT- IN- Lowpass Filter 10pF Offset Correction CZ1 G52358-0, Rev 2.0 02/09/01 CZ2 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com Page 1 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Electrical Characteristics Table 1: DC Specifications Symbol Parameter VCC Power Supply Voltage ICC Power Supply Current(1) IEE Power Supply Current(1) ICCSQ Min Typ 3.135 Max Units 5.5 V Conditions 31 mA VCC = 3.3V 35 mA VCC = 5V 38 mA VCC = 3.3V 43 mΑ VCC = 5V Power Supply Current when Squelched(1) 21 mA VCC = 3.3V 25 mA VCC = 5V IEESQ Power Supply Current when Squelched(1) 24 mA VCC = 3.3V 28 mA VCC = 5V ISQ Squelch Input Current 0 PSSR Power Supply Rejection Ratio 20 400 µA 30 dB f < 2MHz NOTE: (1) See Figure 5 for supply current measurement setup. Table 2: DC Specifications Symbol Parameter VIN JD JR tR, tF VN RDIFF Data Rate Input Voltage Range Deterministic Jitter Random Jitter Rise and Fall Times Input Referred Noise Differential Input Resistance fL Low Frequency Cutoff VSQ Output Signal When Squelched VCML CML Output Voltage ZO Output Resistance Min Typ 3.125 10 55 Max 1200 25 8 100 230 100 2 2 20 1200 1800 20 550 1100 100 Units Gb/s mV ps ps ps µV Ω MHz kHz mV mV mV mV Ω Conditions Peak-to-peak See Note 1 See Note 2, RMS 20% to 80% RMS, IN+ to ININ+ to INCZ open CZ = 0.1µF Output AC-coupled Level = open, RL = 50Ω Level = GND, RL = 75Ω Squelched Single-ended NOTES: (1) Deterministic jitter measured peak-to-peak with K28.5 pattern. (2) Random jitter measured with minimum input. Page 2 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com G52358-0, Rev 2.0 02/09/01 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Table 3: Loss of Signal Specifications Symbol Parameter Min Typ Max Units HLOS LOS Hystersis 3.1 3.3 5.5 dB ILOS LOS Assert/Deassert Time 0.22 0.25 0.28 µs 8.2 VTHA LOS Assert Threshold VTHD 12.8 LOS Deassert Threshold VLOSH LOS Output HIGH Voltage VLOSL LOS Output LOW Voltage 19.8 21.8 Conditions HLOS = 20 log (VTHD/VTHA) mV RTH = 2.5kΩ mV RTH = 7kΩ 57.2 mV RTH = 20kΩ 11.4 mV RTH = 2.5kΩ mV RTH = 7kΩ 75.2 mV RTH = 20kΩ V ILOS = –30µA 0.168 V ILOS = +1.2µA 26.2 29.0 3.3 31.6 Table 4: Loss of Signal Truth Table SQUELCH LOS Output High Low Off Low High On High Low On Low Low On Absolute Maximum Ratings(1) Power Supply Voltage (VCC)............................................................................................................. -0.5V to +6V Maximum Junction Temperature Range .........................................................................................................TBD Storage Temperature Range (TS)................................................................................................. -55°C to +150°C NOTE: (1) CAUTION: Stresses listed under “Absolute Maximum Ratings” may be applied to devices one at a time without causing permanent damage. Functionality at or above the values listed is not implied. Exposure to these values for extended periods may affect device reliability. Recommended Operating Conditions Positive Voltage Rail (VCC).................................................................................................................. 3.3V or 5V Junction Temperature Range (TJ)................................................................................................ -40°C to +100°C Ambient Temperature Range (TA)................................................................................................. -40°C to +85°C G52358-0, Rev 2.0 02/09/01 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com Page 3 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Package Pin Descriptions Figure 1: Pin Diagram Top View TSSOP-16 Package CZ1 1 16 NC CZ2 2 15 SQUELCH GND 3 14 VCC IN+ 4 13 OUT+ VSC7959 IN- 5 12 OUT- GND 6 11 VCC LEVEL 7 10 LOS TH 8 9 LOS Table 5: Pin Identifications Pin Name Pin No. Description CZ1 1 Offset Correction Loop Capacitor. Place capacitor between this pin and CZ2 to alter time constant of offset correction loop. See Detailed Description section. CZ2 2 Offset Correction Loop Capacitor. Place capacitor between this pin and CZ1 to alter time constant of offset correction loop. See Detailed Description section. GND 3 Supply Ground IN+ 4 Noninverted Input Signal IN- 5 Inverted Input Signal GND 6 Supply Ground LEVEL 7 Output Current Level. This pin may either be connected to ground or left unconnected. Connecting to ground causes output current to be 20mA. The output is 16mA when left unconnected. See Detailed Description section. TH 8 Loss of Signal (LOS) Threshold. Connect a resistor from this pin to ground to set the input signal level at which LOS outputs will be asserted. See Application Information section. LOS 9 Inverted Loss of Signal Output. LOS is HIGH for input signals above the threshold programmed by TH. See Detailed Description section. LOS 10 Noninverted Loss of Signal Output. LOS is LOW for input signals above the threshold programmed by TH. See Detailed Description section. VCC 11 Power Supply OUT- 12 Inverted Data Output OUT+ 13 Noninverted Data Output VCC 14 Power Supply SQUELCH 15 Squelch Input. Squelch is disabled if this pin is unconnected or set LOW. When SQUELCH is HIGH, OUT+ and OUT- are forced to static levels. NC 16 No Connection Page 4 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com G52358-0, Rev 2.0 02/09/01 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Bare Die Descriptions Figure 2: Pad Assignments 1597µm (0.06287") Pad1 CAZ1 1597µm (0.06287") Pad 16 NC Pad 2 CAZ2 Pad 15 SQ Pad 3 GNDA Pad 14 VCCA Pad 4 LAINP Pad 13 LAOP VSC7959 Pad 5 LAINM Pad 12 LAOM Pad 6 GNDA Pad 11 VCCA Pad 7 LVL Pad 10 LOS Pad 8 TH Pad 9 LOS Die Size: 1597µm x 1597µm (0.06287" x 0.06287") Pad Pitch: 180µm (0.00709") Pad Passivation Opening: 95µm x 95µm (0.00374" x 0.00374") The back side of the die may either be left floating or connected ot ground. G52358-0, Rev 2.0 02/09/01 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com Page 5 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Table 6: Pad Coordinates Pad Name Pin Name Pad/Pin Number Coordinates (µm) Description X Y CZ1 CZ1 1 270.525 1359.05 Offset Correction Loop Capacitor. Place capacitor between this pin and CZ2 to alter time constant of offset correction loop. See Detailed Description section. CZ2 CZ2 2 80.95 1170.525 Offset Correction Loop Capacitor. Place capacitor between this pin and CZ1 to alter time constant of offset correction loop. See Detailed Description section. GNDA GND 3 80.95 990.525 Supply Ground LAINP IN+ 4 80.95 810.525 Noninverted Input Signal LAINM IN- 5 80.95 630.525 Inverted Input Signal GNDA GND 6 80.95 450.525 Supply Ground 270.525 Output Current Level. This pin may either be connected to ground or left unconnected. Connecting to ground causes output current to be 20mA. The output is 16mA when left unconnected. See Detailed Description section. LVL LEVEL 7 80.95 TH TH 8 270.525 80.95 Loss of Signal (LOS) Threshold. Connect a resistor from this pin to ground to set the input signal level at which LOS outputs will be asserted. See Application Information section. LOS LOS 9 1169.475 80.95 Inverted Loss of Signal Output. LOS is HIGH for input signals above the threshold programmed by TH. See Detailed Description section. LOS LOS 10 1359.05 270.525 Noninverted Loss of Signal Output. LOS is LOW for input signals above the threshold programmed by TH. See Detailed Description section. VCCA VCC 11 1359.05 450.525 Power Supply LOAM OUT- 12 1359.05 630.525 Inverted Data Output LAOP OUT+ 13 1359.05 810.525 Noninverted Data Output VCCA VCC 14 1359.05 990.525 Power Supply SQ SQUELCH 15 1359.05 1170.525 Squelch Input. Squelch is disabled if this pin is unconnected or set LOW. When SQUELCH is HIGH, OUT+ and OUTare forced to static levels. — NC —/16 1169.475 1359.05 No Connection Page 6 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com G52358-0, Rev 2.0 02/09/01 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Detailed Description The VSC7959 is a high speed limiting amplifier with Loss-of-Signal (LOS) detect. The device is designed to operate with a 3.3V or 5V supply in SDH/SONET and Fibre Channel applications up to 3.125Gb/s. The VSC7959 has current-mode logic (CML) outputs. The VSC7961 provides the same functionality as the VSC7959 with positive emitter-coupled logic (PECL) outputs. The key features of the VSC7959 are Loss-ofSignal (LOS) detect, output offset correction, output squelch, adjustable output levels, low power supply current, and fast rise and fall times. The inputs of the device provide 100Ω input impedance between IN+ and IN- and are intended to be DCcoupled. The CML output circuits are designed to tolerate output impedance mismatches and may be AC- or DC-coupled. Loss of Signal (LOS) Detect This features utilizes an RMS power detector with programmable LOS indicator to provide two outputs, LOS and LOS. The input TH is used to set the threshold at which the loss of signal detector outputs, LOS and LOS, change state. See the Loss of Signal Specifications (Table 3) for setting the resistor value between TH and ground. The Loss of Signal Truth Table (Table 4) clarifies how LOS and SQUELCH interact. Optional Squelch Squelch is disabled when SQUELCH is not connected or is set to TTL low level. When SQUELCH is set to TTL high level and LOS is asserted, the data outputs, OUT+ and OUT- are forced to static levels. If LOS is not asserted, the outputs will not be squelched. Offset Correction This feature is provided to ensure that the offsets in the limiting amplifier coupled with its gain do not cause the output buffer to give a false output. Because of the high gain of the amplifier, offset correction using a lowfrequency feedback loop reduces input offset. If no component is placed between pins CZ1 and CZ2, the low frequency cut-off is 2MHz. If a 0.1µF capacitor is placed between CZ1 and CZ2, the low frequency cut-off is lowered to about 2kHz. For Fibre Channel and Gigabit Ethernet applications, leave pins CZ1 and CZ2 open. For ATM/SONET and other scrambled non-return-to-zero (NRZ) applications, place a 0.1µF capacitor between CZ1 and CZ2. This maintains a one-decade separation between the lowest input frequency and the low frequency cut-off. The low frequency cut-off of the offset correction loop is given by the following equation: fOC = 43 / [2π * 35k (CZ + 100pF)] = 196 • 10-6 / (CZ + 100pF) = 196 • 10-6 / (0.1µF + 100pF) = 1.96kHz G52358-0, Rev 2.0 02/09/01 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com Page 7 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Output Level Control The LEVEL pin adjusts the output levels to 20mA when grounded and to 16mA when left unconnected. Figure 3: Supply Current Measurement VCC A ICC IOUT 100Ω 100Ω 100Ω 100Ω IMOD VSC7959 A Supply Current (ICC and IEE) IEE VEE Applications Information Wire Bonding For best performance, gold ball-bonding techniques are recommended. To minimize inductance, keep wire bond lengths short. PCB Layout Guidelines Use high frequency PCB layout techniques with solid ground planes to minimize crosstalk and EMI. Keep high speed traces as short as possible for signal integrity. Short input and output traces will provide best performance. Page 8 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com G52358-0, Rev 2.0 02/09/01 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Package Information TSSOP-16 1. All dimensioning and tolerancing per ASME. Y14.5-1994 2. Controlling dimension: millimeter 3. This outline conforms to JEDEC Publication 95 Registration MS-026 G52358-0, Rev 2.0 02/09/01 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com Page 9 VITESSE SEMICONDUCTOR CORPORATION Advance Product Information VSC7959 3.125Gb/s CML Limiting Amplifier with LOS Detect Ordering Information The order number for this product is formed by a combination of the device type and package type. VSC7959 xx Device Type 3.125Gb/s CML Limiting Amplifier with LOS Detect Package YD: TSSOP-16 W: Dice Waffle Pack Notice Vitesse Semiconductor Corporation (“Vitesse”) provides this document for informational purposes only. This document contains pre-production information about Vitesse products in their concept, development and/or testing phase. All information in this document, including descriptions of features, functions, performance, technical specifications and availability, is subject to change without notice at any time. Nothing contained in this document shall be construed as extending any warranty or promise, express or implied, that any Vitesse product will be available as described or will be suitable for or will accomplish any particular task. Vitesse products are not intended for use in life support appliances, devices or systems. Use of a Vitesse product in such applications without written consent is prohibited. Page 10 © VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: [email protected] Internet: www.vitesse.com G52358-0, Rev 2.0 02/09/01