General Description
The DS1875 controls and monitors all functions for burst-mode transmitters, APD receivers, and video receivers. It also includes a power-supply controller for APD bias generation, and provides all SFF-8472 diagnostic and monitoring functionality. The combined solution of the DS1875 and the MAX3643 laser driver provides APC loop, modulation current control, and eye safety functionality.

Features
♦ Meets All PON Burst-Timing Requirements for Burst-Mode Operation
♦ Laser Bias Controlled by APC Loop and Temperature Lookup Table (LUT)
♦ Laser Modulation Controlled by Temperature LUT
♦ Six Total DACs: Four External, Two Internal
♦ Two 8-Bit DACs, One of Which is Optionally Controlled by MON4 Voltage
♦ Internal 8-Bit DAC Controlled by a TemperatureIndexed LUT
♦ PWM Controller
♦ Boost or Buck Mode
♦ Boost Mode: Uses Optional External Components, Up to 90V Bias Generation
♦ 131kHz, 262kHz, 525kHz, or 1050kHz SelectableSwitching Frequency
♦ APD Overcurrent Protection Using Optional Fast Shutdown
♦ 10 Analog Monitor Channels: Temperature, VCC, Eight Monitors
♦ Internal, Factory-Calibrated Temperature Sensor
♦ RSSI with 29dB Electrical Dynamic
♦ Five I/O Pins for Additional Control and Monitoring Functions, Four of Which are Either Digital I/O or Analog Monitors
♦ Comprehensive Fault-Measurement System with Maskable Laser Shutdown Capability
♦ Two-Level Password Access to Protect Calibration Data
♦ 120 Bytes of Password-1 Protected Memory
♦ 128 Bytes of Password-2 Protected Memory in Main Device Address
♦ 256 Additional Bytes Located at A0h Slave Address
♦ I2C-Compatible Interface for Calibration and Monitoring
♦ 2.85V to 3.9V Operating Voltage Range
♦ -40°C to +95°C Operating Temperature Range
♦ 38-Pin TQFN (5mm x 7mm) Package

Applications
    BPON, GPON, or EPON Optical Triplexers
    SFF, SFP, and SFP+ Transceiver Modules
    APD Controller