General Description
The i7520 is a combined burst mode laser driver and limiting amplifier for use within fiber optic modules for FTTx applications. Used with a low cost serial EEPROM or microcontroller it 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 Off Signal 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 to +85°C ambient, the i7520 is housed in a 32pin, 5x5mm, RoHS compliant, QFN package.

Features
● Burst-Mode common anode laser driver with up to 90mA modulation and 100mA bias current
● 4ns output switching in Burst Mode operation.
● Closed or open loop bias mode with temperature lookup table.
● Temperature compensated modulation current setting stored in look up table
● Limiting amplifier with programmable low pass filter and output swing
● Device settings stored in external 2k EEPROM or MCU
● Support TX-SD function
● Lock APC Loop in 1 burst signal
● Support SPI interface and I2C interface
● Integrate APD voltage control
● Full compliance with SFF8472 and SFP MSA

Applications
   GEPON/GPON ONU Transmitters
   Passive Optical Network (PON) Transmitters
   Fiber-to-the-Home(FTTH) and Fiber-to-the-Premises(FTTP) Broadband Access Systems