ATA7550 5.0V 2.5 Gb/s TIA PRELIMINARY DATA SHEET - Rev 0 FEATURES · · · · · 2.5 Gb/s Differential Output TIA Low Group Delay Single +5V Power Supply Small Size: 0.864mm x 1.014mm 300mW (typ) Power Dissipation GND VCC GND VOUT IIN APPLICATIONS · · · VOUT SONET/SDH OC-48/STM-16 2.5Gb/s DWDM Fiber optic receivers, transceivers and transponders GND CEXT GND GND D1 Package PRODUCT DESCRIPTION The Anadigics ATA7550D1 is a high-speed 5V transimpedance amplifier (TIA) available in bare die form and manufactured using an InGaP based HBT process. The device is used in conjunction with a photodetector to convert an optical signal into a differential output voltage. With its low group delay, the ATA7550 is ideally suited for DWDM applications. VCC VBIAS VOUT IIN VOUT CEXT Figure 1: Circuit Block Diagram 07/01 ATA7550 VCC GND GND 225µm Die Size: 864µm x 1014µm Die Thickness: 178µm VOUT Pad Size: 100µm x 100µm IIN Pad Pitch: 150µm unless VOUT GND 225µm CEXT GND GND Figure 2: Die Size and Layout Table 1: Pad Description PAD 2 D ESC R IPTION C OMMEN T V CC Posi ti ve Supply Voltage +5.0V II N TIA Input Photocurrent i nput C EXT C onnecti on for an external C apaci tor Sets the low frequency cutoff VOUT TIA Output Voltage (Non-i nverted) Logi cal '1' wi th opti cal i nput VOUT TIA Output Voltage (i nverted) Logi cal '0' wi th opti cal i nput PRELIMINARY DATA SHEET - Rev 0 07/01 ATA7550 ELECTRICAL CHARACTERISTICS Table 2: Absolute Maximum Ratings V CC 7.0V IIN 3mApp TS Storage Temp -65 °C to 125 °C Stresses in excess of the absolute ratings may cause permanent damage. Functional operation is not implied under these conditions. Exposure to absolute ratings for extended periods of time may adversely affect reliability. Table 3: Recommended Operating Conditions PAR AMETER Operati ng Voltage Range Operati ng Temperature Range(1) MIN TYP MAX U N IT +4.75 +5.0 +5.25 V -10 D i e Attach Temperature 70 O C 260 O C The device may be operated safely over these conditions; however, parametric performance is guaranteed only over the conditions defined in the electrical specifications. 1. Defined at the interface between the die and the substrate. Table 4: DC Electrical Specifications PAR AMETER MIN TYP MAX U N IT Input Offset Voltage 2.6 V Output Offset Voltage 3.5 V Supply C urrent 60 80 mA Power D i ssi pati on 300 420 mW PRELIMINARY DATA SHEET - Rev 0 07/01 3 ATA7550 Table 5: AC Electrical Specifications (2) PAR AMETER MIN TYP Small Si gnal D i fferenti al Transresi stance (RL - 100 W ) 1500 2000 W Bandwi dth (-3dB) 1600 1900 MHz Low Frequency C utoff (3) 30 kHz Group D elay (1MHz to 1.7GHz; I IN< 250 mApp) ±30 ps Opti cal Sensi ti vi ty (4) -23 dB m Input Noi se C urrent (RMS) (5) Opti cal Overload U N IT 800 -3 (4) Input C urrent at whi ch Output Li mi ts MAX (6) Si ngle-Ended Output Voltage (IIN = 20 mApp) 15 -1 dB m 250 mA 20 mVpp Maxi mum D i fferenti al Output Voltage Output Return Loss (1MHz to 10GHz) nA 500 mVpp 10 Notes: 2. The specifications are based upon the use of a PIN photodetector with a responsivity at 1310nm of 0.9A/W (typical) and a capacitance of CDIODE + CSTRAY = 0.5pF max connected to IIN via a 1nH bond wire. 3. With the use of an external capacitor. 4. Measured at 10-10 BER with a 223 -1 PRBS at 2.488Gb/s. 5. 1.9 GHz bandwidth. 6. Defined as 80% of the maximum output voltage. 4 PRELIMINARY DATA SHEET - Rev 0 07/01 B ATA7550 PERFORMANCE DATA Figure 3: External Capacitor Required for Low Frequency Cutoff 10000 Cext(pf) 1000 100 10 0 50 100 150 200 250 300 350 400 Low Frequency Cutoff (kHz) Figure 4: Differential Output Voltage vs. Input Current 450.0 Output Voltage (mVpp) 400.0 350.0 300.0 250.0 200.0 150.0 100.0 50.0 0.0 0 200 400 600 800 1000 Input Current (uApp) Figure 5: Eye Diagram with an Optical Input Power of -20dBm 10mV/Div. 100ps/Div. PRELIMINARY DATA SHEET - Rev 0 07/01 5 ATA7550 Figure 6: Eye Diagram with an Optical Input Power of -15dBm 20mV/Div. 100ps/Div. Figure 7: Eye Diagram with an Optical Input Power of -5dBm 70mV/Div. 100ps/Div. Figure 8: Eye Diagram with an Optical Input Power of -2dBm 70mV/Div. 6 100ps/Div. PRELIMINARY DATA SHEET - Rev 0 07/01 ATA7550 APPLICATION INFORMATION Photodiode bypass MIM capacitor VBIAS 1nF bypass MIM capacitor 1nH typical VCC 0.1µF DC blocking capacitor VOUT (50Ω) ATA7550 Photodiode VOUT (50Ω) CEXT 0.1µF DC blocking capacitor 1nH typical 1nF MIM capacitor RF and DC ground plane Figure 9: Bonding Diagram PRELIMINARY DATA SHEET - Rev 0 07/01 7 ATA7550 Packaging The ATA7550D1 is provided as bare die. For optimum performance, the die should be packaged in a hermetic enclosure and a low inductance ground plane should be made available for power supply bypassing and ground bonds. When packaging the ATA7550D1, the temperature of the die must be kept below 260°C to ensure the device reliability. The ATA7550D1 does not have backside metal and must be epoxy mounted. A good thermally conductive, silver filled epoxy is recommended for epoxy mounting. A soft silicon/rubber tip collet or pyramidal collet should be used for die mounting, although tweezers can be used with extreme care. Thermosonic ball bonding, at a stage temperature of 150 to 175°C with 1 to 1.3 mil gold wire, is the recommended interconnect technique. The bond force, time and ultrasonic power are all critical parameters and may require optimization to achieve the correct bond without causing bonding pad delamination or damage under the bonding pad. lensed single mode fiber with the photodetector and TIA in an open test fixture under the following conditions: Photodetector active area: 50mm Photodetector capacitance: 0.3pF Photodetector responsivity: 0.90A/W Lensed fiber beam width: 13mm (86.5% of contained power) Lensed fiber focal distance: 3mm When the photodetector and TIA are packaged in a hermetic enclosure, with the fiber optimally aligned to the active area of the photodiode, an improvement in sensitivity should be observed. The bond wire from the photodetector to IIN should be made as short as possible. As the inductance of this connection increases beyond 1nH, more gain peaking will occur and the group delay performance will degrade. Output Connections The ATA7550D1 provides a differential output that must be AC coupled to the next stage of the receiver as the output buffer is not designed to drive a DC coupled 50W load. For single-ended applications, one output of the ATA7550D1 must be AC terminated to a 50W load. CEXT Connection In order to achieve the desired low frequency cutoff, an external capacitor is required. A low inductance surface mount chip capacitor or MIM capacitor is recommended. Sensitivity Measurement The typical sensitivity, as specified in the AC characteristics, is 23dBm. This was measured at a BER of 10-10 with a 2.5Gb/s, 223-1 PRBS, using a 8 PRELIMINARY DATA SHEET - Rev 0 07/01 ATA7550 NOTES PRELIMINARY DATA SHEET - Rev 0 07/01 9 ATA7550 NOTES 10 PRELIMINARY DATA SHEET - Rev 0 07/01 ATA7550 NOTES PRELIMINARY DATA SHEET - Rev 0 07/01 11 ATA7550 ORDERING INFORMATION PAR T N U MB ER ATA7550D 1 PAC K AGE OPTION D1 PAC K AGE D ESC R IPTION Die ANADIGICS, Inc. 141 Mount Bethel Road Warren, New Jersey 07059, U.S.A Tel: +1 (908) 668-5000 Fax: +1 (908) 668-5132 http://www.anadigics.com [email protected] IMPORTANT NOTICE ANADIGICS, Inc. reserves the right to make changes to its products or to discontinue any product at any time without notice. The product specifications contained in Advanced Product Information sheets and Preliminary Data Sheets are subject to change prior to a products formal introduction. Information in Data Sheets have been carefully checked and are assumed to be reliable; however, ANADIGICS assumes no responsibilities for inaccuracies. ANADIGICS strongly urges customers to verify that the information they are using is current before placing orders. WARNING ANADIGICS products are not intended for use in life support appliances, devices, or systems. Use of an ANADIGICS product in any such application without written consent is prohibited. PRELIMINARY DATA SHEET - Rev 0 07/01 12