Optical controller simplifies GPON transceiver design

Sunnyvale, Calif.—Maxim Integrated Products has introduced the DS1865, an optical control, calibration and monitor IC.

Applications include Gigabit Passive Optical Network (GPON) and broadband-passive-optical-network (BPON) triplexers, major components used in Fiber-to-the-Home communications.

The built-in capability of the DS1865 is designed to simplify GPON transceiver design. All control, monitoring, and fault management functions are implemented in the DS1865's CMOS process. 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.

The DS1865 optical controller also integrates several analog functions. An integrated 13-bit ADC includes input scaling, which provides 29dB 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.

The DS1865 includes a 13-bit laser-bias DAC to control the video amplifier and a second DAC to control the boost converter 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 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.

Also available is the DS1863 burst-mode PON controller, which does not include the additional DACs for video amplifier and APD bias control. The DS1863 is available in a 16-pin TSSOP package.

Pricing: The DS1865 and DS1863 cost $1.98 and $1.55, respectively, in 10,000-unit quantities.
Availability: The DS1865 is available now in a 28-pin, 5mm x 5mm TQFN.
Datasheets: DS1865 and DS1863.

Maxim Integrated Products, 1-408-737-7600,

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