open drain output

Hi there.. thanks for coming to the forums. Exciting news! we’re now in the process of moving to our new forum platform that will offer better functionality and is contained within the main Dialog website. All posts and accounts have been migrated. We’re now accepting traffic on the new forum only - please POST any new threads at . We’ll be fixing bugs / optimising the searching and tagging over the coming days.
2 posts / 0 new
Last post
Last seen: 2 years 2 months ago
Joined: 2018-03-01 18:22
open drain output


I want to use the open drain output feature on the chip. I have a one shot pulse generator attached to the pin that configured as a open drain with a pull up. I would like the pin output to be held high and switch to ground when the one shot pulse is given as an input to this pin. Is this the correct way to use this feature? I have attached a simple design file that recreates what I am trying to do. Can you point out what needs to be added to it in order to work correctly? Will I need to use an external fet switch to achieve desired behavior?

Device Number: 
Last seen: 2 years 8 months ago
Joined: 2018-01-31 12:50
Hi vmore, yes this is correct

Hi vmore, yes this is correct way to use one shot feature, but you should use open drain NMOS with pull-up resistor or PMOS with pull-down. So please choose desired case in the output pin settings (PIN20 of your design). Here is the waveform of the corrected design in the attachment. Yellow line input PIN4, blue line output PIN20.