
Si4770/77-A20
8. Reset, Powerup, and Powerdown
Setting the RSTB pin low will disable analog and digital circuitry, reset the registers to their default settings, and
disable the bus. Setting the RSTB pin high will bring the device out of reset.
The powerup mode powers up the device and provides mode selection. Mode selections include the following:
?
?
AM, FM reception (Si4770/77-A20 only).
Crystal oscillator or reference clock input
A powerdown mode is available to reduce power consumption when the part is idle. Putting the device in
powerdown mode will disable analog and digital circuitry while keeping the bus active.
VIO 1
VIO 2
VD
VA
100 μsec min
RSTB
100 μsec min
SCL
46
SDA
POWER_UP Command
Figure 27. Startup Timing
Rev. 0.9