Marchear
Newbie level 2
Hello everyone,
I'm having trouble with operating high speed flip-flops such as the MC100EL31 from ON. The first of these problems was having to introduce myself to the concept of ECL standards, as at first I was trying to operate my gates with 0-5V inputs. Now that I understand this though, I'm still having trouble operating a simple D-type flip-flop.
For now I'm just doing some tests to see how these work, and I'm not having much success. I've put my S (set) input on a low level, D on a high, and I'm feeding my circuit two clocks (around 30 kHz), one in the clock input and the other in the Reset. I've phase-shifted them so that my clock input's rising edge occurs when my reset is low. The idea pretty much is to have my output go high when my clock goes high (S and R are low, D is high, therefore Q goes high on a rising edge) and then have my output go low when R goes high, therefore being able to change the size of my pulses at the output.
My output is not behaving how I wish however. It does have a neat rising edge when it's supposed to (when R is low and my clock input goes high), however when my reset signal goes high, instead of dropping within a few hundred picoseconds as expected, the signal slowly ramps down to low level (about 3V according to the spec sheet). It then goes back up once my clock rises again.
I must specify that my setup is far from optimal, although I really wouldn't have expected it to be a problem when working at such low frequencies. My IC is soldered on an adapter which in turn is pinned into a breadboard. I'm receiving my clock signals from a card that I have control over, however the clock I get is -0.5V to 0.5V, so I have to add an about 3.5V bias to all my signals in order to make sure they meet the values in my spec sheet. The only way I've found to bias these signals unfortunately right now is by using a voltage divider with my source, so it's really shaky in my opinion.
If anyone can help me understand why I can't get a proper output even at such a low frequency, I would be really grateful. So far I've usually always worked with TTL and so forth, but right now this is giving me more than a little trouble, and I've done a lot of looking and researching so far without much success. Thanks in advance!
I'm having trouble with operating high speed flip-flops such as the MC100EL31 from ON. The first of these problems was having to introduce myself to the concept of ECL standards, as at first I was trying to operate my gates with 0-5V inputs. Now that I understand this though, I'm still having trouble operating a simple D-type flip-flop.
For now I'm just doing some tests to see how these work, and I'm not having much success. I've put my S (set) input on a low level, D on a high, and I'm feeding my circuit two clocks (around 30 kHz), one in the clock input and the other in the Reset. I've phase-shifted them so that my clock input's rising edge occurs when my reset is low. The idea pretty much is to have my output go high when my clock goes high (S and R are low, D is high, therefore Q goes high on a rising edge) and then have my output go low when R goes high, therefore being able to change the size of my pulses at the output.
My output is not behaving how I wish however. It does have a neat rising edge when it's supposed to (when R is low and my clock input goes high), however when my reset signal goes high, instead of dropping within a few hundred picoseconds as expected, the signal slowly ramps down to low level (about 3V according to the spec sheet). It then goes back up once my clock rises again.
I must specify that my setup is far from optimal, although I really wouldn't have expected it to be a problem when working at such low frequencies. My IC is soldered on an adapter which in turn is pinned into a breadboard. I'm receiving my clock signals from a card that I have control over, however the clock I get is -0.5V to 0.5V, so I have to add an about 3.5V bias to all my signals in order to make sure they meet the values in my spec sheet. The only way I've found to bias these signals unfortunately right now is by using a voltage divider with my source, so it's really shaky in my opinion.
If anyone can help me understand why I can't get a proper output even at such a low frequency, I would be really grateful. So far I've usually always worked with TTL and so forth, but right now this is giving me more than a little trouble, and I've done a lot of looking and researching so far without much success. Thanks in advance!
