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