high speed cmos question

Other Hardware General Electronics
1

hello,

I am having problems with a circuit. It is shorting somewhere. I have just realised, I have accidentally used a high speed cmos chip instead of a 4000 series.

If I apply over 6v to a high speed cmos chip, (specifically the 74HC4060) could it short my circuit, and make the battery I am using to power the circuit feel hot to the touch?

Thanks
Twogan

2

Applying >6V to a 74HC4040 will likely destroy it. If your battery is hot to the touch it is supplying a LOT of current. It sounds like your circuit (or at least parts of it) are destroyed.

--
The QuadRAM shield: add 512 kilobytes of external RAM to your Arduino Mega/Mega2560

3

If I apply over 6v to a high speed cmos chip, (specifically the 74HC4060) could it short my circuit, and make the battery I am using to power the circuit feel hot to the touch?

That might not be the problem... How much over 6V?

Do you have a multimeter? If so, you can measure the resistance of the chip between 5V and ground to check if it's shorted. Usually, if the chip is burned-out, the chip itself will overheat.

With these inexpensive parts, it's always a good idea to buy a couple extra chips. And, if it's in a socket, it's easy to try another one...

Where I work, I've accidently connected 12V to a 5V board several times. :frowning: Usually, the RAM chip burns-out, and a few times the CPU has burned-out. (The RAM is soldered-in, but thankfully the CPU is in a socket.) But, the regular 74xx logic chips never seem to burn out at 12V.

Another board I test has a voltage regulator on board. I always run 6 - 6.5V into the board to test the regulator. When the regulator is bad, or if the regulator-bypass jumper is installed wrong and 6V gets applied to all of the chips, nothing bad happens. (That's why I run it at 6V... I need to feed-in more than 5.5V to test the regulator, but I want to keep the voltage at a safe level...)

4

Many thanks for the information.

the ic that is listed for the circuit is a CD4060BC. The closest I can find to buy at maplin is a HCF4060BE
http://www.maplin.co.uk/cmos-logic-hcf-hef-4000-series-31820

Is this the right chip ?

Many Thanks
Twogan

5

Yes that's a standard 4000 series (15V) chip. Carefully check your circuit for shorts before reconnecting that battery BTW(!)