Figure 5.20-2 Typical host-side circuit for ALARM output

VRTC is specified to work down to 1.1V across the environmental operating conditions of the GS64. Integrators may discover in controlled environments that the VRTC interface will function reliably as low as 0.8V, so best practice would be to design the circuitry to operate down to 0.7V.

5.20.3 ALARM Utilization as a Wake-up

The ALARM output can be used by the host application to wake up from standby or hibernation mode, but it can also be used to completely power up the host application. The example below shows how the ALARM output (marked Out on Figure 5.20-2, and In on Figure 5.20-3) triggers the enabling of the main power to the application. The application has a parallel hold transistor (V4), and a Start Button.

Figure 5.20-3 Example of host wake-up circuit

LZT 123 1836

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