Author Topic: M74HC595 vs CD4094BC  (Read 6450 times)

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Offline nardevTopic starter

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M74HC595 vs CD4094BC
« on: November 26, 2012, 09:34:58 pm »
Can somebody pls help me to match pins on these two IC's

As far as i see, these two IC's are very similar one to another, both 8 bit shift registers, WITH OUTPUT LATCHES (3 STATE)

I need to know what pin [1-16] in M74HC595 matches what pin [1-16] in CD4094BC.

I have problems identifying pins STROBE, DATA, CLOCK, OUTPUT ENABLED, Q's, Qs

Here you can find data sheets:

M74HC595: http://www.datasheetcatalog.org/datasheet2/c/0hek9e6rpc50aywfc8085prha4cy.pdf

CD4094BC: http://www.jaycar.com.au/images_uploaded/CD4094BC.PDF

Thank you
 

Offline westfw

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Re: M74HC595 vs CD4094BC
« Reply #1 on: November 27, 2012, 01:10:25 am »
The CD4094 has a much wider supply voltage range, and is much slower (min max clock about 1MHz vs 5MHz.)  Whether 1MHz is "fast enough" is a separate question...
 

Offline c4757p

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Re: M74HC595 vs CD4094BC
« Reply #2 on: November 27, 2012, 02:05:44 am »
STROBE = RCK, CLOCK = SCK, Output enable = G (but is active HIGH on the 4094 and active LOW on the 595). The behavior of STROBE is subtly different though - on the 595, all output propagation and latching is done on the rising edge of RCK. On the 4094, it seems (I've never used it before, but according to the datasheet) that data is latched on the falling edge, then propagated to the outputs on the rising edge. So you need a full pulse, whereas with the 595 you just need an edge.
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Offline c4757p

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Re: M74HC595 vs CD4094BC
« Reply #3 on: November 27, 2012, 02:10:50 am »
The datasheet is your friend, and not just the pinout. Look at the block diagram, look at the timing diagram (yeah, I know, they suck, but there is information there that you won't see elsewhere), and read all the text.
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Offline nardevTopic starter

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Re: M74HC595 vs CD4094BC
« Reply #4 on: November 27, 2012, 06:50:48 am »
@c4757p thank you very much.

westfw, both would suite my needs
 

Offline Kremmen

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Re: M74HC595 vs CD4094BC
« Reply #5 on: November 27, 2012, 06:54:04 am »
Then take the 595. The polarities of its signaling are sucjh that you can combine the output strobe/clock and enable into one signal unless you specifically need them separate. Than simplifies the circuit a little bit. I always use 595s in display and key scanners and it has yet to fail me  8)
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Online nctnico

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Re: M74HC595 vs CD4094BC
« Reply #6 on: November 27, 2012, 07:42:35 am »
TI and ST have chips called TPIC6x595 (x=B, C depending on the current rating) which are open drain versions of the HC595. As an extra feature the reset pin on these chips also reset the output register.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 


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