SBAS989 April 2019 PCM1840
PRODUCTION DATA.
The power-supply sequence between the IOVDD and AVDD rails can be applied in any order. However, keep the SHDNZ pin low until the IOVDD supply voltage settles to a stable and supported operating voltage range. After all supplies are stable, set the SHDNZ pin high to initialize the device. Assert the SHDNZ pin high only when all hardware control pins (MSZ, MD0, MD1, FMT0, and FMT1) are driven to the voltage level for the device desired mode of operation.
For the supply power-up requirement, t1 and t2 must be at least 100 µs. For the supply power-down requirement, t3 and t4 must be at least 10 ms. This timing (as shown in Figure 53) allows the device to ramp down the volume on the record data, power down the analog and digital blocks, and put the device into hardware shutdown mode.
Make sure that the supply ramp rate is slower than 1 V/µs and that the wait time between a power-down and a power-up event is at least 100 ms.
The PCM1840 supports a single AVDD supply operation by integrating an on-chip digital regulator, DREG, and an analog regulator, AREG. However, if the AVDD voltage is less than 1.98 V in the system, then short the AREG and AVDD pins onboard.