CD4050AE vs CD4050BE

Download the CD4050A datasheet from

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Dave M
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Life is like a roll of toilet paper; the closer to the end, the faster it goes.

Unicorn Electronics. I have never had a problem with anything from there before... I can't help but think that there might be a difference between the AE and BE suffix???

If the device were damaged by static, is it possible that the inputs would have more load?

Grant

The 4xxxB family has a has added input diodes for ESD protection. There may be more differences, but I'm not sure.

I never had any trouble with the B family, but the A parts I used to get from Radio Shack had a high failure rate. This, however, was a LONG time ago.

Bob

Where did you buy these parts?

Best regards, Spehro Pefhany

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If I remember correctly, the A series had a max. voltage of 10 whereas the B series has a max. voltage of 20. The high and low logic levels are 90% or

18V when supplied by 20V and 10% or 2 volts for the B series. The high and low levels for 10 volts series are 9 and 1, respectively. So a logic high would have to be 9 volts or above or for a logic low 1 volt or below. The higher values provide more noise immunity. At least that was the thought. I'm not sure the B series would work well with a supply voltage of 5V. As this is all from memory, take it with a bit of salt.

I think I have some old databooks lying around and will take a look.

Al

There should be virtually no current going into or out of the inputs for applied voltages of 0..12V, even with the Vcc open or shorted to Vss. Either they are entirely fried, your pin numbers are wrong, or they are actually a different kind of part.

Best regards, Spehro Pefhany

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My memory is that the 4000 series cmos had a voltage range from 3 to 18 from the getgo. If I'm not mistaken, the B suffix were buffered and had a hard time being forced into such things as analog amplifiers and oscillators.

The guaranteed OUTput of the 4000 series is (as a percentage of Vdd) 90% high and 10% low, while the INput had guaranteed switching rates of 70% and

30% respectively. You always had a guaranteed noise margin of 20%, 3.6 volts at 18 volts Vdd and 1 volt at 5 volts Vdd.

Jim

7

18 from

hard

oscillators.

90% 70% and 3.6

My recollections are similar. I know that there were definite areas where buffered CMOS could not be interchanged for unbuffered devices.

This TI document refers to this fact in the background paragraph.

While this doc specifies unbuffered devices as being marked UB I think this only applied well after the introduction of the buffered series. Initially, only the RCA 4000 (unbuffered) series existed and I think they may have begun to use the A suffix to differentiate from the B series when the latter started to appear more commonly. My old RCA literature may have some further info.

In article , logjam wrote: [snip]

There is little difference except that the -B version has a higher supply and input voltage range.

The 4050 does have a weakness on the inputs. It is designed to operate with a logic 1 that can exceed the Vcc, up to 20V for the 4050B. In order to do this there is little or no protection against a positive input overvoltage.

Your apparent high current taken by the inputs does suggest damaged parts.

--
Tony Williams.

My old RCA CMOS databook has both data sheets; the main difference is that the 'B' is good for 3-18V power, and the 'A' is good for 3-12V power. Input limits are 20V for 'B' and 12V for 'A'. Both are intended to be driven from higher voltage than the power supply.

(+) power is on pin 1, (-) power is on pin 8.

Other differences are minor (guaranteed sink current at 5V is 3.2 mA for the 'B' and 3 mA for 'A').

Are you sure you got real CD4050BE's? Motorola had a part line with numbers beginning like 40xx but they were Motorola's own version of TTL and had nothing to do with the similar CD-series CMOS parts.

It's hard to imagine them being counterfeit parts - it'd be like counterfeiting pennies! - but on the surplus market large batches of mislabeled or just plain defective parts show up quite regularly. The older the chips, or the lower in the distribution chain you go, the more likely what you got were factory rejects or floor sweepings. Are you sure you didn't get these through a time warp from Poly Paks?

Tim.

Ahah! Now I remember, the MC4050 was a decade counter and maybe a display decoder used in lots of 70's/80's vintage frequency counters. It won't work nothin like a CD4050.

Tim.

But the OP specifically said "CD4050BE", which is nothin' like "MC4050". But maybe the parts are marked differently from what s/he thinks they are.

Best regards, Spehro Pefhany

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Precisely.

Jim

-- There are only 10 kinds of people in the world. Those who count in binary and those who don't