Other Parts Discussed in Thread: TPS3808, TPS3890
Hello
I have a circuit where I'm using a TL7702B to monitor the main supply rail (12V), and startup a sequence or other rails which are powered from this. VCC is connected to 12V and I have a potential divider connected to SENSE such that the device will go out of reset when the supply reaches 9V. I have a 10uF capacitor connected between CT and GND. I have a few questions about this circuit:
* With the 10uF cap, I'm seeing a delay between #RESIN going high and #RESET going high of about 150mS which seems much shorter than the equation in the data sheet suggests. Can you suggest why this might be?
* Is there a practical limit to the size that this capacitor should be? I'd ideally like about 300mS of delay.
* On page 13 of the data sheet, it talks about a resistor in series with the capacitor if SENSE is monitoring VCC. Is this required in my case as SENSE is connected to VCC via a potential divider (tens of K ohms), I read this as meaning it's only required if the connection is direct.
* I'm pulling #RESET up to 3.3V and RESET down to GND via 10K resistors. Is this OK, or should #RESET be pulled up to VCC only?
Thanks
Martin