SLAS748G March 2011 – January 2024 DAC3482
PRODUCTION DATA
The DAC3482 allows exact phase alignment between multiple devices even when operating with the internal PLL clock multiplier. In PLL clock mode, the PLL generates the DAC clock and an internal OSTR signal from the reference clock applied to the DACCLK inputs so there is no need to supply an additional LVPECL OSTR signal.
For this method to operate properly the SYNC signal should be set to reset the PLL N dividers to a known state by setting pll_ndivsync_ena in register config24 to 1b. The SYNC signal resets the PLL N dividers with a rising edge, and the timing relationship ts(SYNC_PLL) and th(SYNC_PLL) are relative to the reference clock presented on the DACCLK pin.
Both SYNC and DACCLK can be set as low frequency signals to greatly simplifying trace routing (SYNC can be just a pulse as a single rising edge is required, if using a periodic signal it is recommended to clear the pll_ndivsync_ena bit after resetting the PLL dividers). Besides the ts(SYNC_PLL) and th(SYNC_PLL) requirement between SYNC and DACCLK, there is no additional required timing relationship between the SYNC and FRAME signals or between DACCLK and DATACLK. The only restriction as in the PLL disabled case is that the DACCLK and SYNC signals are distributed from device to device with the lowest skew possible.
The following steps are required to make make sure the devices are fully synchronized. The procedure assumes all the DAC3482 devices have a DACCLK and OSTR signal and must be carried out on each device.
After these steps all the DAC3482 outputs will be synchronized.