Direct Digital Synthesizer

The 14-bit ISL5314 is a complete direct digital synthesizer (DDS) system in a single 48 Ld LQFP package. A 48-bit programmable carrier NCO (numerically controlled oscillator) and a high-speed 14-bit digital-to-analog converter (DAC) are integrated into a stand-alone DDS. The DDS accepts 48-bit center and offset frequency control information via a parallel processor interface. A 40-bit frequency tuning word can also be loaded via an asynchronous serial interface. Modulation control is provided by 3 external pins. The PH0 and PH1 pins select phase offsets of 0°, 90°, 180°, and 270°, while the ENOFR pin enables or zeros the offset frequency word to the phase accumulator. The parallel processor interface has an 8-bit write-only data input C(7:0), a 4-bit address A(3:0) bus, a Write Strobe (WR), and a Write Enable. The processor can update all registers simultaneously by loading a set of master registers, then transfer all master registers to the slave registers by asserting the UPDATE pin.