DALLAS Semiconductor, represented by Arrow , has introduced the DS1859-020, a new 20kΩ full-scale resistance option of the DS1859 SFP controller/monitor.
The DS1859-020 controls laser-driver bias and modulation currents. It also manages system monitoring functions required for SFF-8472-compliant optical transceivers. The new 20kΩ resistance option provides higher adjustment resolution, which is suitable for calibrating some laser drivers.
The DS1859's high level of integration reduces component count and layout area, and speeds up the design of optical transceivers. Control functionality is comprised of two 256-position, nonvolatile (NV) variable resistors with customer-programmed, temperature-indexed EEPROM lookup tables.
An integrated 12-bit analogue-to-digital converter (ADC), temperature sensor, MSA-compliant register and memory architecture provide SFF-8472 diagnostics monitoring functionality. The device monitors three external analogue signals, as well as Vcc and temperature.
Programmable alarm and warning trip points for all monitored signals alert the system to out-of-tolerance conditions.
Additionally, the device features internal calibration and ADC ranging to increase the dynamic range for received optical power measurement. Communication with the devices is achieved over a two-wire serial interface.
The DS1859 is available in a space-saving 4x4 BGA package (0.8mm pitch) or 16-pin TSSOP. It operates from a 2.7V to 5.5V power supply over a -40°C to +95°C temperature range. An evaluation kit is available.