ICEs spec and graph on small NPNs

If you tie the base to +3.3V, and drive the emitter from your logic, the leakage that matters is Icbo, and your high-voltage turnoff is better than in the grounded-emitter case because the emitter can be pulled up (by the collector leakage current) above base voltage.

Well heck that was easy. The inverting function is handy as well.

thanks!

With a Vebo of 6.0 volts won't that cause a problem? Maybe I don't understand the circuit. The control line is 0 to 15 volts through a 1 Mohm resistor, right? Reverse biasing the emitter with 15 volts even through a 1 Mohm resistor would break the EB junction, no?

Well, you gotta test it. And test from numerous manufacturers, and a number of date lot codes from each manufacturer. That is a "must do" to find a reliable source, especially for quantity. You may be forced to buy (almost) complete lots after finding a few good lots. You might also discover that testing one from a reel to a given spec that the result will allow a go-no-go for use of its lot code in production. Get an agreement in writing that a lot will be held until you accept/reject and that the tested reel will be accepted for return after testing.

Have fun with your test fixture and with testing + data logging.

Icbo has to be shunted by the base biasing network in common-emitter situations, or sunk by the drive circuit, without allowing the base terminal voltage to rise into a conduction Vbe condition.

If you ever worked with germanium parts, or HV switcher, you'd have become aware of the issue PDQ.

RL

RL

....by the way, the leakage doubles with every x degrees of temperature, so 200C operation needs very careful control. I don't think 1M drive impedances have any place there.

RL