Driving a transistor array

Will there be any problem driving one of these transistor arrays

Upon closer inspection of the datasheet, I would revise than collector current down to 350 mA.

relay, on each Darlington collector. The flip flops

Darlingtons so with 7 in a chip that will leave 5 unused

I am still new to all this.

You had better be careful about burning up your array(s) if you put more than about 150 mA into each of the 7 devices in a package. The 2 Amps (or so) you mention cannot be switched by just one of those devices.

Maybe you should be looking a power MOSFET rather than a Darlington transistor array.

It means something a bit too involved to explain in all its glory. For your purposes, the issue is: What will be the voltage drop between the collector-emitter terminals when the device is supposed to be switched on? I urge you to consult the datasheet about that.

I plan on driving either 1 to 4 LEDs in parallel, or a 12v around 2 or so amp relay, on each Darlington collector. The flip flops will be driving nothing else, just the Darlington array. I need 16 Darlingtons so with 7 in a chip that will leave 5 unused Darlingtons on the one of the 3 arrays or 1 on one chip and 2 on the others. I am still new to all this. What exactly does it mean to have saturation on the output?

amp relay, on each Darlington collector. The flip

Darlingtons so with 7 in a chip that will leave 5 unused

others. I am still new to all this.

I imagine you are right. But I've seen and wired some pretty big relays.

Well, saturation is kind of a funny thing for the Darlington transistor pair. The input transistor can be readily saturated but the output transistor is generally not saturated, having its base drive modified such that its base and collector voltages are about equal. So, using the term "saturation" loosely to mean "as on as can be", there is no reason the HCT device cannot cause that to occur in the Darlington. But for the more precise definition, requiring an excess of carriers in the base region and a forward biased collector-base junction, the output transistor certainly cannot be brought to that state.

The reason I thought this might matter to the OP is that Darlingtons often present a dissipation issue in switching application due to their drop while in the on state and that drop can be significant with respect to the load voltage as well.

amp relay, on each Darlington collector. The flip flops

Darlingtons so with 7 in a chip that will leave 5 unused

I am still new to all this.

I think he means that the relay is reated for a 2A load NOT that it requires 2A to operate. Also, what in the datasheet leads you to believe that the HCT part can't drive the darlingtons to saturation?

amp relay, on each Darlington collector. The flip

Darlingtons so with 7 in a chip that will leave 5 unused

I am still new to all this.

To clarify, yes I did mean a relay that is rated for a 2A load.

I've been looking at that data sheet and I don't really understand a lot of what it is saying. On page 4 it has the chart with all the values and refers you to diagrams on page 5. Most of the diagrams say "Open" by the output of the clamping diode. Doesn't that mean the Darlington is off?

One line says Vce and has 1V typical for a 200ma load. Does that mean that 1 volt will be dropped by the Darlington? If so I will need to make a significant change to my voltage to drive my high intensity LED's. For the 12V relay, that will probably have something more like

I don't understand what the Vi(on) numbers are trying to tell me. For the SN75469 in the MAX column they vary from 5V to 8V depending on the collector current. What exactly does that mean? Is that the maximum voltage the input line can handle? What about the minimum voltage needed to turn the Darlington on?

Then the Vf for the clamp diode is 1.7V .... does that mean there will be 1.7V drop from my supply?

Ii(off) seems obvious and Ii seems to be well with in what my flip flop can provide. I assume Ir is the amount of revers current that will flow for inductive kick back from a relay?

Finally what about Icex? Is that the minimum amount of current the collector needs to stay on?

Thanks for everyones help. I really need to get a good book. The problem is most books about things I am interested in are either way too slow paced, or over my head. I learn this kind of thing very quickly and often find beginner type books very slow paced.