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Latch 74HCT573

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antek

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Does Anyone know how to use 74HCT573, I read it's a latch, and i need like 5 latches that's way i want to use this chip, but i'm completly new in digital electronics, so if somebody could help me, i wolud be very thaknful
 
The datasheet **broken link removed**

looking at the datasheet, you need to connect pins 1 (output enable, active when low) and 10 (gnd) to ground and pins 20 and 11 (latch enable (active high) to your +supply. then pins 2-9 are your latch inputs and 12-19 are your latch outputs.
 
thank you for the answer

thanks for replay,

but i need to know if it works as a latch that wolud be made from let say NAND Gates, because i need like 5 switches that after close and reopen would stay on.

In other words I need a circuit that would be able to remeber position on, even if the switch would be open.
I dont know if i explained it good enought but thanks
 
at school we're building a machine it's called I think ruby goldberg or somthing similar
and my team was thinking if we can use an electronics circuit that as the ball goes down, it would hit something like a switch(the switch would be made from two pieces of a metal) and after that hit, one led would switch to ON and stay ON , whatever the switch would switch to on or off.
I found out that a latch would work great, so i need to know if that chip also would work
 
lol sorry about the appearence , figured i'd try paint to draw the circuit..
the resistor on the D3 input should be high 100K or so..
the resistor on the output depends on the .. say 100 ohms ..
the diode is really an LED ..
you can connect up to eight switches in this fashion..
sorry the latch enable should be connected to Vcc also..
 

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williB said:
jrz that link takes forever to load :roll:

well if you dont like my datasheet, then you can find your own :?
:lol:
looking at the output current though, it a high level current and a low level current. The high level current is -2.6mA and the low level is 24mA. this means that he will have to connect the cathode to the 74573 and the annode and resistor to +vcc.
Or he can use a transistor to supply the current.
 
The '573 is a transparent latch. It doesn't work the way you guys are describing it. Here's a quote from the datasheet:

"The “573” consists of eight D-type
transparent latches with 3-state true
outputs. When LE is HIGH, data at
the Dn inputs enter the latches. In this
condition the latches are transparent,
i.e. a latch output will change state
each time its corresponding D-input
changes.
When LE is LOW the latches store the
information that was present at the
D-inputs a set-up time preceding the
HIGH-to-LOW transition of LE."

In other words, when LE is high, each D input passes directly to its corresponding Q output. When LE transitions low, all Q outputs hold the logic levels that were present at the time of that transition, and remain latched until LE goes high again, at which time they resume tracking their inputs.
You can use a quad NOR or NAND latch (CD4043 or CD4044).
 
i think somone made a mistake on the data sheet..
i dont see how it is possible to have a positive output voltage of 3.4 V and have the the output current flowing into the device ???
 

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williB said:
i think somone made a mistake on the data sheet..
i dont see how it is possible to have a positive output voltage of 3.4 V and have the the output current flowing into the device ???
By convention, current out of a pin is negative.
 
What you are describing is called a "one shot." There are a lot of ways to do it, discretely or even with a 555. Do a search if you're interested.

j.
 
John Sorensen said:
What you are describing is called a "one shot." There are a lot of ways to do it, discretely or even with a 555. Do a search if you're interested.

j.
It's a oneshot if he wants it to automatically reset after a certain amount of time. Otherwise, it's a latch.
 
thanks williB for the circuit but ther is a problem, imean ther is no reset button thtawould switch the led to off :) once i switche to on i stay on all the time
 
antek said:
sorry i get it , i need to conect - to the pin an it would switch yo off :)
thanks everybode :)
Re-read my description of the way the 573 works. It won't do what you want. As I said, you can use CD4043 or CD4044.
 
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