I need a circuit to act as a watchdog to a micro (which is not powered (instead of in a sleep mode)most of the time).
it needs to be low power (< ~4uA) and non-programmable. So no I2C RTCs or MCUs.
I've looked at RC timers combined with a comparator but extremely large resistors and caps become too expensive for the timeout required (25hours).
I've also looked at using shift registers to divide out an astable multivibrator to the correct time, but ICs (counter/dividers/flip-flops) i've been able to find draw too much current - ~8uA alone.