| Electronics > Beginners |
| 10937p-50 chip? |
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| Ian.M:
Sorry it took me so long to reply - I've had a lot of non-EE stuff going on so didn't have time for a properly considered reply earlier. --- Quote from: hydrolisk1792 on May 30, 2018, 11:26:00 am ---Now I'm assuming on the LED verso I don't need the negative bias for the pull down resistors, I can just put them at ground, right? Or should I keep that true to the datasheet? --- End quote --- The off-state output leakage per driver is specced at 10uA max. so you don't actually need any pulldown resistors for the LED version unless you are driving a BJT or MOSFET. The ULN2x03 chips include an internal base-emitter pulldown. You certainly don't need a large negative bias for the pulldowns - that is only to get a high enough Vak for sufficient brigtness for multiplexed VFDs. For any output that needs a pulldown, simply take the pulldown to whichever rail (Gnd or -10V) sinks the current from the LED cathode drivers. |
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