Hello everyone. I'm looking for an IC in which when I apply 5v to it, the chip's output will go open drain for 15s-20s. I tried looking at watchdog timers, but they require pulses for it to time out. Does anyone have any suggestions on IC's that can do this?

 

Why not just a transistor or mosfet?

 

Why not just a transistor or mosfet?

I would use a mosfet, but I'm afraid I will have limited space to work with.

 

You are looking for something smaller than a single transistor? That will be difficult. How small do you need this to be?

 

You need a power-on reset circuit, something like a MAX823, MAX824, MAX825

15-20 seconds is unusually long.

 

You need a power-on reset circuit, something like a MAX823, MAX824, MAX825

15-20 seconds is unusually long.

Bigger than a transistor/mosfet though.. So if thats truly a requirement then he is out of luck..

 

Bigger than a transistor/mosfet though.. So if thats truly a requirement then he is out of luck..

Mitsubishi used to do power on reset chips - I think their semiconductor division became part of Renaiaance along with that of Hitachi.

 

You are looking for what's called a power supervisor. They are ubiquitous and packages in 3 lead transistor packages (sorry, all I see are SMD so they are incredibly tiny.

Linkie

 

You are looking for what's called a power supervisor. They are ubiquitous and packages in 3 lead transistor packages (sorry, all I see are SMD so they are incredibly tiny.

Linkie

Some PC ATX PSUs have a dedicated chip for the power good line, but I can't remember if they're the same thing or not.

Even recently, I've found 5-pin SIL types as opposed to microscopic SMD.