FTTH Network

125Mbps to 2.5Gbps FTTx Burst-Mode Laser Driver/Postamplifier


The PHY2078 is a combined burst-mode laser driver and limiting amplifier for use within fiber optic modules for FTTx applications. Used with the PHY1095 or PHY1097 transimpedance amplifiers and a low cost serial EEPROM, the device forms a complete PON diplexer silicon solution.

The transmit block includes a high-frequency modulator and a bias current generator. The bias current can be controlled either by a fast-settling APC loop or in open-loop mode, which uses a temperature lookup table. The receiver includes a limiting amplifier with programmable bandwidth. A signal-detect/loss-of-signal (LOS) function is implemented using the input signal modulation amplitude with user-selectable threshold and hysteresis.

Operating with a 3.3V supply and rated from -40°C to +95°C ambient operating temperature range, the PHY2078 is housed in a 32-pin, 5mm x 5mm, RoHS-compliant, QFN package.

Key Features
Burst-Mode Common Anode Laser Driver with Up to 80mA Modulation and 90mA Bias Current
7ns Output Switching in Burst Mode
Power-Saving Mode with Zero Bias and Modulation Current Between Bursts
Closed or Open-Loop Bias Mode with Temperature Lookup Table
Temperature-Compensated Modulation Current
Limiting Amplifier with Programmable Lowpass Filter and Output Swing
Device Settings Stored in External 2k EEPROM