74LS73A (flip-flop)

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caine

Posted: Mon Mar 19, 2007 11:15 am

Guest

I'm doing a IC tester and it is able to only input high and low
voltages to the Input pin of the IC. What input should i set for the
CLK input pin of 74 series IC such as 74LS73A (flip-flop)?
The datasheet for the 74LS73A (flip-flop) is accessible from

http://rabbit.eng.miami.edu/info/datasheets/74LS95B.pdf

Peter Bennett

Posted: Mon Mar 19, 2007 7:42 pm

Guest

On 19 Mar 2007 09:15:00 -0700, "caine" <thensiujing@gmail.com> wrote:

Quote:

That datasheet is for a 74LS95B. Change the part number at the end to
74LS73 to get the 74LS73 datasheet.

The '73 is a negative edge triggered device. Initially set the clock
high, then change it to low, and the output should switch to match the
D input. Change the D input, then set the clock up and down again to
see the output change again.

The 74LS73 data sheet has a very nice truth table that illustrates how
the part works.

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Peter Bennett, VE7CEI
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Jamie

Posted: Tue Mar 20, 2007 7:37 pm

Guest

Peter Bennett wrote:

Quote:

On 19 Mar 2007 09:15:00 -0700, "caine" <thensiujing@gmail.com> wrote:

I'm doing a IC tester and it is able to only input high and low
voltages to the Input pin of the IC. What input should i set for the
CLK input pin of 74 series IC such as 74LS73A (flip-flop)?
The datasheet for the 74LS73A (flip-flop) is accessible from

http://rabbit.eng.miami.edu/info/datasheets/74LS95B.pdf

That datasheet is for a 74LS95B. Change the part number at the end to
74LS73 to get the 74LS73 datasheet.

The '73 is a negative edge triggered device. Initially set the clock
high, then change it to low, and the output should switch to match the
D input. Change the D input, then set the clock up and down again to
see the output change again.

The 74LS73 data sheet has a very nice truth table that illustrates how
the part works.

must be careful with the part number..

if it has an "A" or the LS73A for example,. it's a Negative Edge
trigger and the Q's will reflect the JK inputs on the falling
edge of the clk otherwise, if i'm reading the DOC's correct for the
NON "A" version. The Q's will reflect the JK input while the CLK is
held high. The Q's will toggle if both JK are on at the same time,
and putting them to both OFF and on again will toggle the Q's.
When the clk finally drops, it will then latch onto the last value.

at least that is the why i understand it, it's been a while since
i played with logic from a chip, i do it mostly in uC these days.

--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

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