ATA7601 5.0V 10 Gb/s TIA Preliminary Data Sheet - Rev 1 FEATURES · 10 Gb/s Differential Output TIA · +5V Power Supply · Low Group Delay · Small Size: 0.85mm x 0.914mm · 325mW (typ) power dissipation GND GND VCC VOUT IIN VOUT GND APPLICATIONS · SONET OC-192 · 10 Gb/s DWDM · 10 Gb/s Ethernet CEXT GND GND D1 Package Product Description The ANADIGICS ATA7601D1 is a 5V high-speed transimpedance amplifier (TIA) for 10 Gb/s applications available in bare die form and manufactured using an InGaP HBT process. The device is used in conjunction with a photodetector to convert an optical signal into a differential voltage that must be AC coupled to a post amplifier. With its low input noise, a sensitivity of better than -19dBm (BER <10-10) can be achieved with the ATA7601D1. Figure 1: Circuit Block Diagram VCC VBIAS VOUT IIN VOUT CEXT ATA7601 Absolute Maximum Ratings V CC 7.0V IIN 4mApp TS Storage Temp -65 °C to 125 °C 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 -40 85 C O 1. Defined at the interface between the die and the substrate. DC Characteristics PAR AMETER MIN TYP MAX U N IT Input Offset Voltage 1.35 V Output Offset Voltage 3.0 V Supply C urrent 65 95 mA Power D i ssi pati on 325 500 mW AC Characteristics (2) PAR AMETER MIN TYP Small Si gnal D i fferenti al Transresi stance (RL - 100W) 900 1100 W Bandwi dth (-3dB) 8.0 9.0 GHz 30 kHz Low Frequency C utoff (3) Group D elay (1MHz to 8GHz) -25 Opti cal Sensi ti vi ty (4) +25 -19.5 Input Noi se C urrent (RMS) (5) Opti cal Overload MAX -3 Input C urrent at whi ch Output Li mi ts (6) Maxi mum D i fferenti al Output Voltage Output Return Loss (1MHz to 10GHz) dB m 350 mA 400 10 Preliminary Data Sheet - Revision 1 03/01 mA -2 2. The specifications are based upon the use of a PIN photodetector with a responsivity at 1550nm of 0.85A/W and a capacitance of CDIODE + CSTRAY = 0.3pF max connected to IIN via a 0.8nH bond wire. 3. With the use of an external capacitor. 4. Measured at 10-10 BER with a 223 -1 PRBS at 10Gb/s. 5. 11GHz bandwidth. 6. Defined as 80% of the maximum output voltage. 2 ps dB m 1.8 (4) U N IT mV dB ATA7601 Pad Description PAD D ESC R IPTION C OMMEN T V CC Posi ti ve Supply Voltage +5.0V IIN 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 Figure 2: Die Size and Layout 245µm 292µm GND GND VCC Die Size: 850µm x 914µm 189µm Pad Size: 114µm x 114µm unless otherwise noted VOUT Pad Pitch: 150µm unless otherwise noted VOUT IIN GND 225µm CEXT GND GND 353µm 183µm Preliminary Data Sheet - Revision 1 03/01 3 ATA7601 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: Eye Diagram with an Optical Input Power of -19dBm 10mV/Div. 25ps/Div. Figure 5: Eye Diagram with an Optical Input Power of -9dBm 40mV/Div. 4 25ps/Div. Preliminary Data Sheet - Revision 1 03/01 ATA7601 Figure 6: Eye Diagram with an Optical Input Power of -4dBm 70mV/Div. 25ps/Div. Figure 7: Differential Output Voltage vs. Input Current Output Voltage (mVpp) 400 350 300 250 200 150 100 50 0 0 100 200 300 400 500 600 700 800 Input Current (uApp) Preliminary Data Sheet - Revision 1 03/01 5 ATA7601 Figure 8: Typical Bonding Diagram Application Information V BIAS +5V 1nF GND V CC GND 50Ω transmission lines ATA7601D1 V OUT I IN V OUT * GND 50Ω CEXT GND GND 1nF * This ground bond can be omitted if it interferes with the placement of the photodetector. 6 Preliminary Data Sheet - Revision 1 03/01 50Ω ATA7601 Packaging The ATA7601D1 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. 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 ATA7601D1 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 ATA7601D1 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 19.5dBm. This was measured at a BER of 10-10 with a 10Gb/s, 223-1 PRBS, using a lensed single mode fiber with the photodetector and TIA in an open test fixture under the following conditions: Photodetector active area: 32mm Photodetector capacitance: 0.2pF Photodetector responsivity: 0.85A/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. Device Modeling and Simulation S-parameter files of the TIA are available on the Anadigics web site (http://www.anadigics.com) or upon request. Also included on the web-site is a virtual sample. This is an encrypted model of the TIA that can be downloaded into the ADS simulation environment. Preliminary Data Sheet - Revision 1 03/01 7 ATA7601 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 discontinue any product at any time without notice. The Advanced Product data sheets and product specifications contained in this data sheet are subject to change prior to a products formal introduction. The information in this data sheet has been carefully checked and is assumed to be reliable. However, ANADIGICS assumes no responsibility 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 - Revision 1 03/01 8