Sunnyvale, Calif. Maxim Integrated Products has introduced a highly integrated optical control, calibration, and monitor IC. The DS1865 integrates GPON power-leveling functionality, a laser bias average-power-control (APC) loop, video amplifier control, and SFF-8472 diagnostic and alarm features. These capabilities make the DS1865 suitable for all BPON and GPON triplexer applications.
The DS1865 controller is optimized to work with the MAX3643 burst-mode laser driver for a compact GPON system solution. By implementing all control, monitoring, and fault management functions in an inexpensive CMOS process, the total solution cost for a GPON transceiver is minimized, said Maxim.
The DS1865 optical controller also integrates several analog functions. An integrated 13-bit ADC includes input scaling, which provides 29 dB of dynamic range. The built-in temperature sensor is factory-calibrated and has 50% less error than competing solutions, according to Maxim. A tracking error lookup table enables compensation for laser-monitor diode error that occurs across temperature. This latter feature further increases the accuracy of the laser power control, said the company.
The DS1865 includes a 13-bit laser-bias DAC, more than four times better than existing solutions, to control the video amplifier and a second DAC to control the boost converter (MAX5026) for the APD bias. The APD bias can be controlled across temperature to ensure that the APD operates in the correct gain range.
The RF output power of the video amplifier (MAX3654) is controlled using the MAX4003 to sense the output RF power, an op amp to make a feedback loop, and the DS1865's DAC output to provide a set point for the control loop.
With this built-in capability, the DS1865 simplifies GPON transceiver design in several ways, according to Maxim. The APC loop controls the laser's bias across temperature and aging, thus removing the requirement for a laser-bias lookup table (LUT). The modulation control DAC and APC loop have eight bits of resolution, and another three levels of scaling: +0dB, -3dB, and -6dB. This scaling ability allows a single register to control the ONU power level. The DS1865 memory map conforms to SFF-8472 specification, making this device simple to use and design in.
The DS1865 operates from a 2.85-V to 5.5-V power supply over a -40°C to +95°C temperature range. Also available is the DS1863 burst-mode PON controller, which does not include the additional DACs for video amplifier and APD bias control.
Pricing: Available in a 28-pin 5 x 5 mm TQFN, the DS1865 is priced at $1.98 (10,000-up, FOB USA). The DS1863 is available in a 16-pin TSSOP package, and is priced at $1.55 (10,000-up, FOB USA). Evaluation kits are available for both devices.
Product information: PON controllers
Datasheets: DS1865 and
Maxim Integrated Products, 1-800-998-8800, www.maxim-ic.com