So if a pull-up resistor of appropriate value is properly connected between the output and the supply voltage, the output logic is HI, and the output is driving a TTL input, is the output said to be sourcing current to the TTL input?An open collector output can sink a current to 0V but it cannot source a current. It needs to have a pullup resistor or transistor added for its output to source a current and be high.
That would be conventional current. Not "electron flow."If we say an output source current it means the current flows out of the chip. If way say the output sinks it means the current flows in the chip. By the way you dont need to have a pullup resistor to drive a TTL input because a floating TTL input is taken as high.
I agree (if it's an NPN). Can you link to a datasheet that uses the opposite convention?Just take source and sink with a grain of salt[ what ever that means ] ,because IC data sheets do not all agree with each other on the subject; maybe check date of publication.To me an open collector sinks.
I don't get it. Output high into a grounded LED is sourcing. Maybe I don't understand what you are saying.This was it,I think.: NATIONAL SEMICONDUCTOR. CMOS DATA BOOK, Cat# 62-1375, Pub. 1977; CD4511BC , " Output [ source ] VDD=15,I-OH=20mA, V-OH=13.95V " ;" Output [sink ] , V-DD = 15V,V-OL= 1.5V, I-OL= 7.8 mA". The output high side drives [sinks] the anode of a LED, cathode at ground. Let it just be user beware.
by Aaron Carman
by Jake Hertz
by Jake Hertz
by Don Wilcher