The AD5770R 6-channel 14 bit current output DAC of Analog Devices has an on-chip reference and serial peripheral interface (SPI), which has a smaller footprint and higher power efficiency than existing bias solutions. Small form factor allows 100G/400G coherent data modules to migrate to small form factor CFP modules, while still providing the necessary output signal range and biased laser communication modules required for performance.
Function block diagram
The AD5770R provides a digital programmable current source with multiple output ranges from - 60 mA to+300 mA, 14 bit resolution. Each DAC channel can work on a wide power rail from 0.8 V to AV (DD) - 0.4 V, optimizing power efficiency with a low drop out of 0.245 V. This reduces the support circuit required without degrading the performance, and reduces the design complexity and system footprint.
Time sequence diagram
