SCAS847J July 2007 – June 2025 CDCE925 , CDCEL925
PRODUCTION DATA
When using an external reference clock, XIN/CLK must be driven before VDD ramps to avoid risk of unstable output. If VDDOUT is applied before VDD, TI recommends keeping VDD pulled to GND until VDDOUT is ramped. If the VDDOUT is powered while VDD is floating, there is a risk of high current flowing on the VDDOUT.
The device has a power-up control connected to the 1.8V supply. This disables the device until the 1.8V supply reaches a sufficient voltage level. Then, the device switches on all internal components, including the outputs. If there is a 3.3V VDDOUT available before the 1.8V, the outputs stay disabled until the 1.8V supply reaches a certain level.