SLASFL3 September 2026 DAC90802
PRODUCTION DATA
The DAC90802 works with a four-wire (extendable to six-wire) SPI. The digital interface of the device can be an FPGA or processor, as shown in Section 8.2.3. The DAC90802 has two LDAC input options for synchronous output update for each channel. In ac-signal-generation applications, the jitter in the LDAC signal contributes to the signal-to-noise ratio (SNR) at the output. Therefore, the LDAC signals must be generated from a low-jitter clock source in the FPGA or processor. All active-low signals (LDAC, RESET, CS) can be pulled up to VIO using appropriate resistors. When operating at high SCLK frequencies, use appropriate termination resistors(optional), as shown in Figure 8-6. Digital signals which are unused can be tied to either VIO or to the ground.
Phase noise on LDAC can degrade DAC output noise, especially at higher output frequencies. A stable (better than ±50ppm frequency stable), low random jitter (≤ 3.0ps) clocks (like TI's CDC6C) are recommended.