The charge pin has an internal open drain FET which is on (pulls down to V_SS) during the first charge only (independent of TTDM) and is turned off once the battery reaches voltage regulation and the charge current tapers to the termination threshold set by the PRE-TERM resistor.

The charge pin will be high impedance in sleep mode and OVP and return to its previous state when the condition is removed.

Cycling input power, pulling the TS pin low and releasing or entering precharge mode will cause the CHG pin to reset and is considered the start of a first charge.