The following is a quote from one of the DS1307 datasheets.
SQW/OUT (Square Wave/ Output Driver) - When enabled, the SQWE bit set to 1, the SQW/OUT pin outputs one of four square wave frequencies (1 Hz, 4 kHz, 8 kHz, 32 kHz). The SQW/OUT pin is open drain which requires an external pullup resistor. SQW/OUT will operate with either Vcc or Vbat applied.
Based on the above, if the DS1307 is running on Vbat power, but SQW is operating with Vcc, and there is an LED connected to SQW, does this LED add to the drain on Vbat? I assume not, but I wanted to know for certain.
SQW/OUT (Square Wave/ Output Driver) - When enabled, the SQWE bit set to 1, the SQW/OUT pin outputs one of four square wave frequencies (1 Hz, 4 kHz, 8 kHz, 32 kHz). The SQW/OUT pin is open drain which requires an external pullup resistor. SQW/OUT will operate with either Vcc or Vbat applied.
Based on the above, if the DS1307 is running on Vbat power, but SQW is operating with Vcc, and there is an LED connected to SQW, does this LED add to the drain on Vbat? I assume not, but I wanted to know for certain.