Clarification on the ICs

[electronicslearner77]

Hi,

I am trying to build a circuit for driving a seven segment display basically to count seconds. Now my doubt is I have purchased the following ICs a 555 timer, 4510 BCD up down counter, 4511 seven segment driver. i have read about different logic level standards like CMOS, TTL etc. So, do I need the ICs to be from the same family? Do I need to manually check on the IC whether it is from CMOS family or TTL or any other family? And for the 555 timer it is just written ne555p (11A3YRB) does it also belong to some logic family. It is the first time i am putting together all the hardware pieces together after simulation, So some help would get me going.

Thanks in advance,
Regards,
Satya

 

[ericgibbs]

hi Satya,
The 4510 and the 4511 are the same CMOS family, the NE555 is TTL and 7555 CMOS. Note there are many name types for the 555 timer series.

The types you have are compatible.

 

[electronicslearner77]

Hi Eric,

Small clarification, you are saying 4510 and 4511 is CMOS family and NE555 is TTL. So, when I interface these ICs from different families will it not create problem or do I need to make some interface logic between the TTL and CMOS?

Thanks in advance,
Regards,
Satya

 

[ericgibbs]

Hi Eric,

Small clarification, you are saying 4510 and 4511 is CMOS family and NE555 is TTL. So, when I interface these ICs from different families will it not create problem or do I need to make some interface logic between the TTL and CMOS?

Thanks in advance,
Regards,
Satya

Hi Satya,
On the 3 types you have listed there will not be a compatibility problem.

There are problems when mixing CMOS and TTL logic, due the output voltage levels and input voltages not meeting the required specification of the 'other' family. Referred to as 'threshold' levels.

I will post a chart or link for you.

This link is useful.
http://www.interfacebus.com/voltage_threshold.html

Note: some of the 'earlier' logic CMOS will work from 3V thru 15V supply voltage, some of the later CMOS types are around the TTL supply levels.

Its advisable to check the datasheets for the different families.
**broken link removed**

 

[colin55]

You won't have any problems when operating from 6v to 15v.

 

[dr pepper]

I agree with that, you can use the 555 to clock the 4510, so long as your talking up to a few khz or so.

 

[edeca]

Lecture 4 and 5 of the MIT 6.002 series explain the theory behind the graphs that Eric posted and why the input/output thresholds are so important.

You can find them here: https://ocw.mit.edu/courses/electri...s-and-electronics-spring-2007/video-lectures/