Alliance Semi launches I2C EMI reduction IC

To address EMI reduction in embedded systems, PC peripherals and digital consumer applications, Alliance Semiconductor Corp. has launched the AS80M25XX family of dual phase-locked loop (PLL) clock chips.
The AS80M25XX series is I2C-configurable, which lets customers configure the functional parameters of the devices from an external I2C master unit through the I2C bus.

The PLL clock chip series is a versatile spread-spectrum frequency modulator designed for a wide range of clock frequencies. The AS80M25XX allows system designers to verify system functionality and performance under different spread spectrum clocking schemes.

PLL modulation
To spread the bandwidth of a synthesized clock, the AS80M25XX modulates the PLL thus lowering the peak amplitudes of its harmonics. This method results in lower system EMI compared to the typical narrow band signal produced by oscillators and some clock generators.

The new frequency modulator reduces the number of circuit board layers and shielding thus providing customers system cost savings.

The AS80M2516A has two on-chip PLLs with four frequency outputs - two per PLL. It also has an input frequency range of 6MHz to 80MHz in Spread Spectrum mode or 2MHz to 200MHz in nonspread spectrum mode. It has a supply voltage of 3.3V and an output frequency range of 4MHz.

Alliance is also offering an evaluation board and programming software for the AS80M2516A.