PRODUCT BRIEF GiGA LXT19908 ® 10Gbit/s Limiting Amplifier Device Product Description GiGA®, an Intel company, has developed the LXT19908 wide bandwidth Limiting Amplifier (LIA) device for use in SDH STM-64, SONET OC-192, G.709, DWDM and 10GE receiver applications in optical communication systems. The LXT19908 has a high dynamic range, providing linear gain higher than 40dB. The high input sensitivity LIA accepts input signals below 2Vpp differential and tolerates a maximum of 1Vpp for single-ended applications. The output swing is adjusted by the Voltage Output (VSET) control and can be varied between 0 and 1Vpp, which facilitates interoperability between CDR and DEMUX components. The input and output ports are internally terminated Flexible Input/Output Design at 50Ω, and an external offset control can be imple- The GiGA LXT19908 inputs may be either AC- or DC- mented to optimize sensitivity of the CDR. coupled, with input termination through VINREF/VINREFN Low power dissipation is approximately 260–800mW, depending on the output swing (no heat sink required). The LXT19908 is assembled in a 16-pin 5.8 x 5.8 mm ceramic QFP package, using small form factor design pins as shown in Figure 1. If the inputs are AC coupled, the LXT19908 features internal DC offset compensation. The outputs have 50Ω termination internally and can also be AC- or DC-coupled. When single-ended input is required, the unused input to reduce the overall size of the PCB. The LXT19908 is manufactured in a proven GaAs technology, offering the performance, stability, and reliability customers require for optical communication systems. should be terminated with 50Ω to ground. For optimal sensitivity, of the decision circuit following the LXT19908, an external offset control can be applied. This works with both DC- and AC-coupled inputs, as well as single-ended and differential configurations. VINREF Key Applications VIN VINN VINREFN VOUT • SDH STM-64 VOUTN • SONET OC-192 GND VEE VSET Figure 1. Input/Output Schematic • DWDM systems • 10Gbit/s Ethernet receivers • OTN, 10Gbit/s FEC with up to 25% overhead Feature Benefit • 40dB single end gain • High dynamic range • Input sensitivity: 2x5mVpp differential and 1x10mVpp single-ended input • Helps increase power budget • Power supply: -5.2V • Easy board design and integration • Adjustable output 0-1Vpp • Interoperability between CDR and DEMUX components • 260-800mW power dissipation • High integration • Ceramic QFP package • No heat sink and small form factor (5.8x5.8 mm) O/E TIA LIA/ AGC CDR DeMUX CLK ASIC CLK Figure 2. Typical receiver line card Typical Receiver Line Card Application Overview Pre-Amplifier Application When the GiGA LXT19908 is used as a pre-amplifier An optical reception system receives an optical with the GD16584 (10Gbit/s) or GD16588 signal and converts it to an electrical signal. The (10.7Gbit/s), optimal sensitivity is obtained when optical receiver, a PIN diode or an Avalanche Photo the adjustable output is set to approximately 400mV Detector (APD) converts the optical input to a small amplitude (600mVpp). The LXT19908 can be electrical current. The current is converted to an coupled directly to the GD16584 or GD16588, electrical voltage by a Trans-Impedance Amplifier as illustrated in the system diagram, Figure 3. (TIA), often called a post-amplifier. The signal from the TIA varies from a few mV to 50mVpp or more, LXT19908 GD16584 and can be passed to an AGC amplifier or a LIA VOUT to obtain a signal with sufficient power to drive the next building block as shown in Figure 2. VOUTN DI DIN The LIA generates an output signal composed of square pulses due to the large internal gain combined with the cutting of the signal extremes. The CDR device converts the analog input signal to a digital bit stream with an associated clock signal. Finally, the serial high-speed data stream is converted to a parallel signal at lower speed, which interfaces with the digital processing system. VSET Figure 3. Pre-Amplifier Application Intel® Internet Exchange Architecture Support Collateral Intel® Internet Exchange Architecture is an end- • LXT19908 Data Sheet to-end family of high-performance, flexible and • LXT99908 Data Sheet Evaluation Board, Footprint and Gerber files scalable hardware and software development building blocks designed to meet the growing • LXT19908 Test Report performance requirements of today’s networks. Based on programmable silicon and software building blocks, Intel® IXA solutions enable faster development, more cost-effective deployment and future upgradability of network and communications systems. Additional information can be found at www.intel.com/IXA GiGA Access Web Site Literature Center www.giga.dk (800) 548-4725 7 a.m. to 7 p.m. CST (U.S. and Canada) International locations please contact your local sales office. GiGA ApS an Intel company Information in this document is provided in connection with products developed by GiGA, an Intel company. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in GiGA’s Terms and Conditions of Sale for such products, Intel assumes no liability whatsoever, and GiGA disclaims any express or implied warranty relating to sale and/or use of Intel products, including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. GiGA products are not intended for use in medical, life-saving, or life-sustaining applications. GiGA may make changes to specifications and product descriptions at any time, without notice. Designers must not relay on the absence or characteristics of any features or instructions marked “reserved” or “undefined.” GiGA reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them. *Other brands and names are the property of their respective owners. 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