READY pin

AN3223

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Doc ID 17553 Rev 2

7

READY pin

It is an open drain output, which provides information about the voltage on the super-

capacitor. The signal is active low. The behavior of this pin depends on the mode of

operation.

7.1

Function of the READY pin in Monitoring mode and Torch

mode (fixed)

voltage in this case. This voltage is set by the VDC_0 and VDC_1 bits in the FEATURE

register. The comparator works with a fixed hysteresis of 200 mV in this case, so the

transition from low to high level occurs when the voltage of the super-capacitor falls to

7.2

Function of the READY pin in Flash mode

voltage again. Unlike Monitoring mode, the transition from low to high occurs when the

super-capacitor voltage falls to 4.2 V. This threshold is fixed and cannot be changed by any

settings of the registers.

Figure 9.

READY pin behavior in Monitoring mode and Torch mode (fixed)

200 mV

V

DCTHRESHOLD

READY pin level

V

SUPERCAP

200 mV

V

DCTHRESHOLD

READY pin level

V

SUPERCAP

AM07803v1