DS12858 Rev 2

9/20

STA5635A

Power management and start-up strategy

19

2

Power management and start-up strategy

The supply available on board of 3.3 V (or 1V8) have to be applied to VCC_RF, VCC_IO

and CHIP_EN (with or without an RC network) pins.

With power supply applied but CHIP_EN inactive the chip is in stand-by mode consuming

just a minimal leakage current. Applying CHIP_EN High, turns-on the LDOs, immediately

after the xtal oscillator and after a delay (td) the rest of the device. On CHIP_EN pin can be

used an optional RC delay to be sure that supply LDOs is set before LDO enable.

Figure 3. Power configuration