| Electronics > Beginners |
| TTL level converter - 1.5V to 5V |
| << < (3/3) |
| FrankBuss:
--- Quote from: rstofer on June 26, 2018, 05:20:09 pm ---TI makes a series of translators but with a quick search all I found was 1.8->3.3V and 3.3V->5V. I didn't see a device that went from 1.5V->5V in one step. Then again, I didn't do a lot of searching. --- End quote --- Digikey is very useful for searching. I found this: http://www.ti.com/lit/ds/symlink/lsf0102.pdf 2 channel, by some analog magic bidirectional without a direction pin, 100 MHz. |
| rstofer:
--- Quote from: FrankBuss on June 27, 2018, 06:54:12 am --- --- Quote from: rstofer on June 26, 2018, 05:20:09 pm ---TI makes a series of translators but with a quick search all I found was 1.8->3.3V and 3.3V->5V. I didn't see a device that went from 1.5V->5V in one step. Then again, I didn't do a lot of searching. --- End quote --- Digikey is very useful for searching. I found this: http://www.ti.com/lit/ds/symlink/lsf0102.pdf 2 channel, by some analog magic bidirectional without a direction pin, 100 MHz. --- End quote --- Outstanding search! I didn't stumble across that device yesterday. I was looking at uni-directional and I probably should have opened up the search. 100 MHz ought to cover VGA. |
| Cj1:
Hm, so looking at the diagram for the LSF0102, it would be wired like: A1:H 1.5V input A2:V 1.5V input B1:H 5V output B2:V 5V output EN:+5V Gnd:Ground It looks like the Vref is for some kind of switching? Im assuming the level converter is always on due to +5V and doesn't need to have switching applied? Or did i read that wrong? |
| Zero999:
--- Quote from: Cj1 on June 28, 2018, 05:35:18 am ---Hm, so looking at the diagram for the LSF0102, it would be wired like: A1:H 1.5V input A2:V 1.5V input B1:H 5V output B2:V 5V output EN:+5V Gnd:Ground It looks like the Vref is for some kind of switching? Im assuming the level converter is always on due to +5V and doesn't need to have switching applied? Or did i read that wrong? --- End quote --- Vref_A and Vref_B are the power supply voltages. Please read the data sheet in full. I know data sheets are often difficult to read, but we're here to help. http://www.ti.com/lit/ds/symlink/lsf0102.pdf |
| rstofer:
When you look at Figure 6, you need to recognize that they are coupling logic at 1.2V, 2.5V and 3.3V. GPIO3 is 1.2V, GPIO 4 is 2.5V and GPIO1,2 are 3.3V It's quite a circuit. VrefA needs to be the lowest level logic voltage, or 1.5V in your case. VrefB needs to be the highest level logic voltage or 5.0V in your case, don't forget the pull-up resistor Ven = 5V Any device that has a 21 page datasheet is going to take some reading. It doesn't seem that the device wants to deal with very much capacitance 30 pf for 100 MHz (50 pf for 40 MHz). I have no idea how much capacitive loading the monitor, cable and PCB are going to provide. I wonder if this circuit is going to require some kind of cable driver. What is driving the other signals? |
| Navigation |
| Message Index |
| Previous page |