Not Recommended for New Designs ONET2511TA www.ti.com SLLS622 – SEPTEMBER 2004 2.5 GBPS TRANSIMPEDANCE AMPLIFIER WITH RSSI Check for Samples: ONET2511TA FEATURES 1 • • • • • • • • • DESCRIPTION 2.5 GHz Bandwidth 4.0 kΩ Differential Transimpedance 10 pA/√Hz Typical Input Referred Noise 2 mA Maximum Input Current Offset Cancellation Received Signal Strength Indication Differential CML Data Outputs Single +3.3V Supply Bare-Die Option The ONET2511TA is a high-speed transimpedance amplifier used in SDH/SONET systems with data rates up to 2.5Gbps. It features a low input referred noise, 2.5GHz bandwidth, 4.0kΩ transimpedance, and a received signal strength indicator. The ONET2511TA device is available in die form and requires a single +3.3V supply. It is very power efficient and dissipates less than 83 mW (typical). It is characterized for operations from –40°C to 85°C. AVAILABLE OPTIONS APPLICATIONS • • • • SONET OC-48 SDH STM-16 APD Preamplifier-Receivers PIN Preamplifier-Receivers TA DIE –40°C to 85°C ONET2511TAY DETAILED DESCRIPTION BLOCK DIAGRAM The ONET2511TA is a high performance 2.5 Gbps transimpedance amplifier that can be segmented into the signal path, filter, and offset cancellation block. The signal path consists of a transimpedance amplifier stage, a voltage amplifier, and an output buffer. The filter circuit provides a filtered VCC for the photodiode. The offset correction circuit uses an internal low pass filter to cancel the DC on the input and it provides a signal to monitor the received signal strength. A simplified block diagram of the ONET2511TA is shown in Figure 1. VCC RSSI 750 W Disable FILTER Offset Cancellation Bandgap Voltage Reference and Bias Current Generation RF + + − − OUT+ IN Transimpedance Amplifier Voltage Amplifier OUT− CML Output Buffer GND Figure 1. Simplified Block Diagram of the ONET2511TA 1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2004, Texas Instruments Incorporated Not Recommended for New Designs ONET2511TA SLLS622 – SEPTEMBER 2004 www.ti.com SIGNAL PATH The first stage of the signal path is a transimpedance amplifier that takes the photodiode current and converts it to a voltage signal. The second stage is a voltage amplifier that provides additional gain. The output of the second stage feeds the output buffer and the offset cancellation circuitry. The third and final signal path stage of the ONET2511TA is the output buffer. The output buffer provides CML outputs with an on-chip 50Ω back-termination to VCC. FILTER CIRCUITRY The filter pin provides a filtered VCC for the photodiode bias. The on-chip low pass filter for the photodiode VCC is implemented using a filter resistor of 750Ω and an internal capacitor. If additional filtering is required for the application, an external capacitor should be connected to the FILTER pin. OFFSET CANCELLATION AND RSSI The offset cancellation circuitry performs low pass filtering of the output signal of the voltage amplifier. This senses the DC offset at the input of the ONET2511TA. The circuitry subtracts current from the input to effectively cancel the DC. The sensed current is mirrored and is used to generate the RSSI output through an external 10 kΩ resistor. To disable the offset correction loop, the FILTER pin should be tied to GND. BOND PAD DESCRIPTION VCC GND The ONET2511TA is available as bare-die. The location of the bondpads is shown in Figure 2. The circuit is characterized for ambient temperatures between –40°C and 85°C. Table 1 shows the pad descriptions for the ONET2511TA. 6 7 7 6 VCC 8 8 654µm IN 9 N.C. 10 5 ONET 2511TA 9 10 PAD#1 y FILTER 1 5 OUT+ 4 4 OUT– 1 2 ONET2511TA_B2003 3 1,030µm 2 3 GND x RSSI origin 0,0 Figure 2. Bond Pad Assignment of ONET2511TA Table 1. Pad Description of the ONET2511TA PAD SYMBOL TYPE DESCRIPTION 1 FILTER Analog Bias voltage for photodiode (connects to an internal 750-Ω resistor to VCC). To disable offset correction loop connect FILTER to GND. 2 RSSI Analog-Out Analog output voltage proportional to the input data amplitude. Indicates the strength of the received signal (RSSI). 3, 6 GND Supply Circuit ground. 4 OUT- Analog-Out Inverted data output. On-chip 50-Ω back-terminated to VCC. 2 Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA Not Recommended for New Designs ONET2511TA www.ti.com SLLS622 – SEPTEMBER 2004 Table 1. Pad Description of the ONET2511TA (continued) PAD SYMBOL TYPE DESCRIPTION 5 OUT+ Analog-Out Non-inverted data output. On-chip 50-Ω back-terminated to VCC. 7, 8 VCC Supply 3.3-V ± 10% supply voltage 9 IN Analog-In Data input to TIA. Connect to anode of PIN or APD diode. 10 NC Not connected ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) UNIT (2) VCC Supply voltage VOUT+ VOUT- Voltage of OUT+ and Out- (2) -0.3 to 4.0 V VCC –1.5 to VCC +0.5 V VFILTER VRSSI Voltage of FILTER and RSSI (2) -0.3 to 4.0 V mA IIN Current into IN -4 to 4 IFILTER Current into FILTER -8 to 8 mA ESD ESD rating at all pins except IN (3) 2 kV (HBM) ESD rating at IN (3) 1 kV (HBM) TJmax Maximum junction temperature 150 °C TSTG Storage temperature -65 to 85 °C TA Operating free-air tempature -40 to 85 °C (1) (2) (3) Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute–maximum–rated conditions for extended periods may affect device reliability. All voltage values are with respect to network ground terminal. For optimum high-frequency performance, the input pin has reduced ESD protection. RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) PARAMETER VCC Supply voltage TA Operating free-air temperature TEST CONDITIONS MIN NOM MAX 3 3.3 3.6 V 85 °C -40 UNIT DC ELECTRICAL CHARACTERISTICS over operating free-air temperature range, VCC = 3.3 V, TA = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS VCC Supply voltage ICC Supply current VIB Input bias voltage IIN-OVL DC input overload current ROUT Ouput resistance (OUT+, OUT-) RFILTER Photodiode filter resistance (FILTER) MIN TYP MAX 3 3.3 3.6 V 25 35 mA 0.83 1.1 V 0.66 2 Single-ended to VCC mA 50 Ω 750 Ω Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA UNIT 3 Not Recommended for New Designs ONET2511TA SLLS622 – SEPTEMBER 2004 www.ti.com AC ELECTRICAL CHARACTERISTICS over operating free-air temperature range, VCC = 3.3 V, TA = 25°C (unless otherwise noted) PARAMETER IIN-OVL TEST CONDITIONS AC input overload current MIN Input linear range 0.95 < linearity < 1.05 ARSSI RSSI gain 10-kΩ load Z21 Small-signal transimpedance Differential output fH-3dB Small-signal bandwidth CEXTERNAL = 0.85 pF (1) fL-3dB Low-frequency -3dB bandwidth -3 dB, II N < 20 µA DC fH-3dB -RSSI RSSI bandwidth IN-IN Input referred RMS noise Deterministic jitter 40 3000 µAp-p 4000 V/A 5000 Ω 2.5 GHz 7 kHz 4 kHz 640 nARMS 10 pA/√Hz IIN = 10 µA (K28.5 pattern) 21 psp-p IIN = 100 µA (K28.5 pattern) 25 psp-p IIN = 2 mA (K28.5 pattern) 16 Differential output voltage, maximum IIN = 1 mAp-p PSRR Power supply rejection ratio 4 UNIT mAp-p 470 VOD(MAX) (1) MAX 2000 Input referred noise density DJ TYP 2 f < 2 MHz 200 320 55 psp-p 400 mVp-p dB CEXTERNAL= is the total capacitance comprising of the photodiode capacitance, board capacitance, and pad capacitance at the IN bond pad. Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA Not Recommended for New Designs ONET2511TA www.ti.com SLLS622 – SEPTEMBER 2004 APPLICATION INFORMATION Basic Application Circuit Figure 3 shows the ONET2511TA being used as a receiver in a typical fiber optic application. The ONET2511TA converts the electrical current generated by the PIN or APD photodiode into a differential voltage output. The FILTER input provides a DC bias voltage for the photodiode that is low pass filtered by the combination of the internal 750-Ω resistor and internal capacitor. For additional power supply filtering, use an external capacitor CFILTER. The RSSI output is used to mirror the photodiode output current and must be connected via a 10-kΩ resistor to GND or left open. Within the ONET2511TA, the OUT+ and OUT- pins are back-terminated with 50 Ω to VCC. VCC 7 C1 6 OUT+ 8 5 750Ω 9 10 ONET 2511TA C2 PAD#1 OUT– 4 1 2 3 ONET2511TA_B2003 CFILTER (optional) RSSI 10kW GND Figure 3. Basic Application Circuit Board Layout Careful attention to board layout parasitics and external components is necessary to achieve optimal performance with a high performance transimpedance amplifier like the ONET2511TA. Recommendations that optimize performance include: 1. Minimize total capacitance on the IN pad by using a low capacitance photodiode and paying attention to stray capacitances. Place the photodiode close to the ONET2511TA die in order to minimize the bond wire length and thus the parasitic inductance. 2. The external filter capacitance CFILTER may have an impact on the transfer function of the TIA and must be chosen with care based on the module implementation. 3. Use identical termination and symmetrical transmission lines at the differential output pins OUT+ and OUT-. 4. Use short bond wire connections for the supply terminals VCC and GND. Provide sufficient supply voltage filtering. Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA 5 Not Recommended for New Designs ONET2511TA SLLS622 – SEPTEMBER 2004 www.ti.com CHIP DIMENSIONS AND PAD LOCATIONS 7 6 8 5 ONET 2511TA 654µm 9 10 y PAD#1 4 1 2 3 ONET2511TA_B2003 1,030µm origin 0,0 x Figure 4. Chip Dimensions and Pad Locations Figure 5. Chip Layout Table 2. Pad Locations and Description PAD LOWER LEFT COORDINATE UPPER RIGHT COORDINATE SYMBOL TYPE DESCRIPTION Bias voltage for photodiode x [µm] y [µm] x [µm] y [µm] 1 30 84 115 169 FILTER Analog 2 207 30 292 115 RSSI Analog out RSSI output voltage signal 3 384 30 469 115 GND Supply 4 886 112 971 197 OUT- Analog out Inverted data output 5 886 509 971 594 OUT+ Analog out Non-inverted data output 6 384 534 469 619 GND Supply Circuit ground 7 207 534 292 619 VCC Supply +3.3 V ± 10% supply voltage 8 30 534 115 619 VCC Supply +3.3 V ± 10% supply voltage 9 30 384 115 469 IN Analog in Data input to TIA 10 30 234 115 319 NC 6 Circuit ground Not connected Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA Not Recommended for New Designs ONET2511TA www.ti.com SLLS622 – SEPTEMBER 2004 TO46 Layout Example An example for a suggested layout in a 5-pin TO46 ROSA is given in Figure 6 (top view). 0.65mm ONET 2511TA ONET2511TA_B2003 4 OUT– 1 10 9 8 2 3 PAD#1 6 7 1.03mm 5 OUT+ GND VCC RSSI Figure 6. TO46 Layout Example Using the ONET2511TA Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA 7 Not Recommended for New Designs ONET2511TA SLLS622 – SEPTEMBER 2004 www.ti.com TYPICAL CHARACTERISTICS VCC = +3.3 V and TA = +25°C (unless otherwise noted) INPUT REFERRED NOISE vs AVERAGE INPUT CURRENT INPUT REFERRED NOISE vs FREE-AIR TEMPERATURE 600 2200 Input Reffered Noise Current − nA RMS Input Reffered Noise Current − nA RMS 2400 2000 1800 1600 1400 1200 1000 800 600 10 100 500 450 400 350 300 250 200 −40 400 1 550 1000 −20 40 60 Figure 8. DC TRANSFER CHARACTERISTIC (OFFSET CANCELLATION DISABLED) TRANSIMPEDANCE vs FREE-AIR TEMPERATURE 80 100 80 100 75 74 150 73 100 Transimpedance − dBW Differential Output Voltage − mV 20 Figure 7. 200 50 0 −50 72 71 70 69 68 −100 67 −150 66 −200 −100 −80 −60 −40 −20 0 20 40 60 80 100 65 −40 −20 0 20 40 60 Free−Air Tempature − 5C Input Current − mA Figure 9. 8 0 Free−Air Tempature − 5C Average Input Current − mA Figure 10. Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA Not Recommended for New Designs ONET2511TA www.ti.com SLLS622 – SEPTEMBER 2004 TYPICAL CHARACTERISTICS (continued) VCC = +3.3 V and TA = +25°C (unless otherwise noted) SMALL SIGNAL BANDWIDTH vs FREE-AIR TEMPERATURE RSSI OUTPUT VOLTAGE vs AVERAGE INPUT CURRENT 3.0 2.5 2 2.8 RSSI Output Voltage − V Small−Signal Bandwdith − GHz 2.9 2.7 2.6 2.5 2.4 2.3 1.5 1 0.5 2.2 2.1 −40 0 −20 0 20 40 60 80 100 0 Free−Air Tempature − 5C 200 400 600 800 1000 1200 Average Input Current − mA Figure 11. Figure 12. DETERMINISTIC JITTER vs INPUT CURRENT 100 90 Deterministic Jitter − psp−p 80 70 60 50 40 30 20 10 0 10 100 1000 10k Input Current − mAp−p Figure 13. Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA 9 Not Recommended for New Designs ONET2511TA SLLS622 – SEPTEMBER 2004 www.ti.com TYPICAL CHARACTERISTICS (continued) VCC = +3.3 V and TA = +25°C (unless otherwise noted) Differential Output Voltage − 15mV/Div OUTPUT EYE-DIAGRAM AT 2.5 GBPS and 20µAp-p INPUT CURRENT USING A K28.5 PATTERN Time − 100ps/Div Figure 14. Differential Output Voltage − 50mV/Div OUTPUT EYE-DIAGRAM AT 2.5 GBPS and 2 mAp-p INPUT CURRENT USING A K28.5 PATTERN Time − 100ps/Div Figure 15. 10 Submit Documentation Feedback Copyright © 2004, Texas Instruments Incorporated Product Folder Link(s): ONET2511TA PACKAGE OPTION ADDENDUM www.ti.com 5-Sep-2011 PACKAGING INFORMATION Orderable Device ONET2511TAY Status (1) NRND Package Type Package Drawing DIESALE Y Pins 0 Package Qty Eco Plan (2) Green (RoHS & no Sb/Br) Lead/ Ball Finish Call TI MSL Peak Temp (3) Samples (Requires Login) N / A for Pkg Type (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. 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