Present IP is to generate 1.8v supply voltage from an external Button Cell or Lithium Battery. The Lithium Battery will be monitored automatically. When Lithium Battery is connected, the IP core will provide the supply current via both VDD_P and VDD_P2, and Button Cell is only for standby. When Lithium Battery is disconnected, Button Cell will replace it to empower the IP core to supply current via VDD_P, but VDD_P2 is of no avail in this case.

Process: SMIC 0.18um 3.3v/1.8v 1P6M MS process  
Input voltage: Button Cell (AVDD_IS_1): 2.75v~3.0v Lithium Battery (AVDD_IS_2): 3.0v~4.2v  
Output voltage: VDD_P: 1.8v VDD_P2: 1.8v  
Maximum Output Current: IVDD_P>10uA; IVDD_P2 >20uA  
Standby current: IqAVDD_IS_1<0.1uA IqAVDD_IS_2<110uA  
Operating temperature: -40癈~+25癈~+125癈